RE: Calibration supplier for signal generator with pulse modulation
I have used the same antenna calibration lab for over ten years, and they always send me a full frequency range package of VSWR data as well as the Gain and Antenna Factor data. I had never really thought about the usefulness of the VSWR data until I talked with Ken a few years ago about antenna calibrations. Of course, measuring the VSWR on a typical horn antenna is complicated by reflections inside your lab, so, if I have a question, I usually go outside to the company parking lot and point my horn vertically into the sky. Maybe someday the Google satellite will catch me in the act. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Tuesday, August 17, 2010 12:37 AM To: Derek Walton; Price, Edward Cc: emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation For some reason, the list server is rejecting the following message I posted in response to Ed’s: “One answer to that for the bigger horns is to do a visual, and for the smaller horns (all horns actually) a vswr check will suffice to indicate whether the coax to waveguide adapter is sound. Someone else pointed that out, and they are correct. I normally shy away from that sort of measurement at microwave frequencies, because it is touchy, but it is still more accurate than an ARP 958 or other radiated measurement.” Ken Javor Phone: (256) 650-5261 From: lfresea...@aol.com List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Mon, 16 Aug 2010 10:14:13 -0400 To: ken.ja...@emccompliance.com Subject: Re: Calibration supplier for signal generator with pulse modulation He has a good point about adapters From: Price, Edward ed.pr...@cubic.com To: emc-p...@ieee.org Sent: Mon, Aug 16, 2010 9:00 am Subject: RE: Calibration supplier for signal generator with pulse modulation From: emc-p...@ieee.org [mailto:emc-p...@ieee.org mailto:emc-p...@ieee.org? mailto:emc-p...@ieee.org? ] On Behalf Of Ken Javor Sent: Thursday, August 12, 2010 6:31 AM To: Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation And similarly, not because of MU but because of 17025 or perhaps ISO 9000, I’ve seen test equipment that could easily have been calibrated in house, such as current probes, LISNs and a 41 inch rod antenna have to be sent to the calibration lab. This is totally unproductive, except for the calibration lab. And I would argue further that it is detrimental to the discipline, because if you do your own calibration, you understand better how things work. Oh, and my favorite, the calibration of microwave horn antennas, whose properties are entirely set by their linear dimensions. The measurement or verification that their dimensions have not changed since their original acquisition is so much more accurate than the direct measurement of their gain. In fact any passive antenna used in the EMI measurement business can be easily checked visually for dimensional abnormalities, and those with a balun, such as a dipole, biconical or logperiodic can be checked for vswr using a directional coupler; no need for expensive and time consuming annual or semi-annual trips to a calibration facility. If it isn’t physically damaged, and the vswr meets original specs, meaning the balun is good, the antenna is good. Ken Javor Phone: (256) 650-5261 Ken: I completely agree, except…. I have seen a few strange and nasty things happen with horn antennas. 1. Many horn antennas have a coupling pin in the throat of the waveguide to provide for coupling of the RF wave from the waveguide end of the antenna throat to the 50-Ohm coaxial system. This “pin” is often a precision machined and positioned extension of the center pin of a female type N coax connector. The efficiency and VSWR of the antenna is very sensitive to the positioning of that pin, but all is normally fine unless you do something dumb like poke something down the throat of the antenna. But consider what happens if you connect an improperly built coax cable to that antenna connector. In the case where the coax cable center pin extends too far out the end of the cable connector, you can wind up displacing the female connector center pin (and that critical launcher pin inside the antenna). 2. If you use that antenna for both transmit and receive, it’s possible for high RF power (and/or very bad reflections) to create arcing at that launcher pin. You can also soften the dielectric of the antenna connector. Both of these will lead to changes in the antenna efficiency. Sometimes, you may use a very basic horn antenna that ends with simply a waveguide flange. Not much can
RE: Calibration supplier for signal generator with pulse modulation
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Thursday, August 12, 2010 6:31 AM To: Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation And similarly, not because of MU but because of 17025 or perhaps ISO 9000, I’ve seen test equipment that could easily have been calibrated in house, such as current probes, LISNs and a 41 inch rod antenna have to be sent to the calibration lab. This is totally unproductive, except for the calibration lab. And I would argue further that it is detrimental to the discipline, because if you do your own calibration, you understand better how things work. Oh, and my favorite, the calibration of microwave horn antennas, whose properties are entirely set by their linear dimensions. The measurement or verification that their dimensions have not changed since their original acquisition is so much more accurate than the direct measurement of their gain. In fact any passive antenna used in the EMI measurement business can be easily checked visually for dimensional abnormalities, and those with a balun, such as a dipole, biconical or logperiodic can be checked for vswr using a directional coupler; no need for expensive and time consuming annual or semi-annual trips to a calibration facility. If it isn’t physically damaged, and the vswr meets original specs, meaning the balun is good, the antenna is good. Ken Javor Phone: (256) 650-5261 Ken: I completely agree, except…. I have seen a few strange and nasty things happen with horn antennas. 1. Many horn antennas have a coupling pin in the throat of the waveguide to provide for coupling of the RF wave from the waveguide end of the antenna throat to the 50-Ohm coaxial system. This “pin” is often a precision machined and positioned extension of the center pin of a female type N coax connector. The efficiency and VSWR of the antenna is very sensitive to the positioning of that pin, but all is normally fine unless you do something dumb like poke something down the throat of the antenna. But consider what happens if you connect an improperly built coax cable to that antenna connector. In the case where the coax cable center pin extends too far out the end of the cable connector, you can wind up displacing the female connector center pin (and that critical launcher pin inside the antenna). 2. If you use that antenna for both transmit and receive, it’s possible for high RF power (and/or very bad reflections) to create arcing at that launcher pin. You can also soften the dielectric of the antenna connector. Both of these will lead to changes in the antenna efficiency. Sometimes, you may use a very basic horn antenna that ends with simply a waveguide flange. Not much can go wrong with the antenna, but almost everyone will use this antenna with a waveguide-to-coax adapter. Again, all the things I said above now apply to your adapter. I make a practice of sending my flanged horn antennas (at least the ones below 18 GHz) out for calibration with a permanently mated coax adapter mounted on them. That way, my cal data includes the adapter. A good object lesson hit me just a few weeks ago. When I sent my 12 GHz to 18 GHz flanged horn antenna out to my cal lab, I put a brand new female-female SMA adapter on the waveguide adapter (that adapter is odd; it has an SMA male coax connector). Later, my cal lab called me to ask how long I had been using that adapter. Turns out that the beautiful gold plated brand new adapter had a faulty center pin, and the VSWR and loss went completely wild (a bad resonance) at around 15 GHz. Ed Price ed.pr...@cubic.com blocked::mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
Is 20 dB acceptable to me? Absolutely not. But then I don't use MU to cover up my inadequacies :-) Low hanging fruit? How about we start with: EUT construction repeatability, including parts substitution in manufacturing EUT operation conditions, and interfaces being exercised EUT placement/configuration for anything other than a PC Influence of support table/system Arrangement of cables and manipulation Testing at a distance NOT consistent with it's use Not detecting emanations with an antenna likely to be the susceptible one in practice Only testing the emissions detected with receive height of 1 to 4 metres @ 10 metres away ignoring emissions above and below EUT A good start there, how about we continue.. Operator, or software interpretation of where to QP Behavior of measuring instrument to out of band, and even measuring range signals or spurious Evaluation against a limit that doesn't reflect sensitivity of likely receivers Notice nothing here is in the MU list of things in CISPR, but from experience almost every one of these would swamp any error accounted for from MU in CISPR 16-4-2 or LAB 34. Anyways, enough for now, there's a Boddingtons with my name on it... Good night, Derek. From: Deniz Demirci deniz.demi...@ntscorp.com To: lfresea...@aol.com; b...@toprudder.com; emc-p...@ieee.org Sent: Thu, Aug 12, 2010 9:17 pm Subject: RE: Calibration supplier for signal generator with pulse modulation Hi Derek, So, we all are comfortable with 20 dB differences on round robins J No need to improve anything Please enlighten us about the “Low hanging fruits” Regards, Deniz From: lfresea...@aol.com [mailto:lfresea...@aol.com mailto:lfresea...@aol.com? ] Sent: Thursday, August 12, 2010 7:34 PM To: Deniz Demirci; b...@toprudder.com; emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation Hi Deniz, what entity is going to do something of little value unless forced to? Of course MU is done for auditing reasons. Very few tests require it in EMC.. Please do not bring up radio tests, I'm referring to EMC. Clause 5.4.1 states... .and, where appropriate, an estimation of the measurement uncertainty as well as statistical techniques for analysis of test and/or calibration data. If you are ASKED to do MU outside of this it's either because your assessing body is over zealous, or your assessor is uneducated. You must push back and say NO! Failure to do this is punishing your client, and more important the consumer, which includes me and I'm taxed enough already! I wouldn't consider myself a novice in MU, or EMC testing, but I can learn. That said, I have yet to see a genuine advantage for MU improving measurement. What does calculating MU have to do with quantifying accuracy? All it does is put windows about what you might be measuring. Now, here's a chance to back a stance by a fellow assessor who has campaigned for ( and I support his idea ) that ISO 17025 should be split into two documents: one for test, the other for calibration. I wholeheartedly support the addressing of MU in the calibration document, and there being NO mention in the test document. ( Dan, if your reading, these are my words not yours... ) Cheers, Derek. From: Deniz Demirci deniz.demi...@ntscorp.com To: lfresea...@aol.com; b...@toprudder.com; emc-p...@ieee.org Sent: Thu, Aug 12, 2010 7:59 pm Subject: RE: Calibration supplier for signal generator with pulse modulation If MU is only for audit purpose, it won’t help at all. If you are using MU for your benefit, there are always some improvement opportunities in your test setup. If you can’t quantify how inaccurate you are, how do you improve anything? quote I'm amused to read you make adjustments for your MU being larger. Keep in mind were kind of measuring jello.../quote Uncertainty and measurement errors are different. Systematic error can only be compensated, not MU You should not make any adjustments based on MU. It is an uncertainty not a correction factor (don’t get amused) Plain EMC may be still measuring a jello. But more accuracy is necessary in “Radio” certifications. It will be really odd if your measurements are +/- 4 dB off for the radiated power J MU is a nice tool if you know/want how to use it OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com mailto:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations http://www.ntscorp.com/about/locations From: lfresea...@aol.com mailto:lfresea...@aol.com [mailto:lfresea...@aol.com mailto:lfresea...@aol.com? ] Sent: Thursday, August 12, 2010 5:43 PM To: Deniz Demirci; b...@toprudder.com mailto:b...@toprudder.com ; emc-p...@ieee.org mailto:emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation Again, how do you guarantee
RE: Calibration supplier for signal generator with pulse modulation
Hi Derek, So, we all are comfortable with 20 dB differences on round robins J No need to improve anything Please enlighten us about the “Low hanging fruits” Regards, Deniz From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Thursday, August 12, 2010 7:34 PM To: Deniz Demirci; b...@toprudder.com; emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation Hi Deniz, what entity is going to do something of little value unless forced to? Of course MU is done for auditing reasons. Very few tests require it in EMC.. Please do not bring up radio tests, I'm referring to EMC. Clause 5.4.1 states... .and, where appropriate, an estimation of the measurement uncertainty as well as statistical techniques for analysis of test and/or calibration data. If you are ASKED to do MU outside of this it's either because your assessing body is over zealous, or your assessor is uneducated. You must push back and say NO! Failure to do this is punishing your client, and more important the consumer, which includes me and I'm taxed enough already! I wouldn't consider myself a novice in MU, or EMC testing, but I can learn. That said, I have yet to see a genuine advantage for MU improving measurement. What does calculating MU have to do with quantifying accuracy? All it does is put windows about what you might be measuring. Now, here's a chance to back a stance by a fellow assessor who has campaigned for ( and I support his idea ) that ISO 17025 should be split into two documents: one for test, the other for calibration. I wholeheartedly support the addressing of MU in the calibration document, and there being NO mention in the test document. ( Dan, if your reading, these are my words not yours... ) Cheers, Derek. From: Deniz Demirci deniz.demi...@ntscorp.com To: lfresea...@aol.com; b...@toprudder.com; emc-p...@ieee.org Sent: Thu, Aug 12, 2010 7:59 pm Subject: RE: Calibration supplier for signal generator with pulse modulation If MU is only for audit purpose, it won’t help at all. If you are using MU for your benefit, there are always some improvement opportunities in your test setup. If you can’t quantify how inaccurate you are, how do you improve anything? quote I'm amused to read you make adjustments for your MU being larger. Keep in mind were kind of measuring jello.../quote Uncertainty and measurement errors are different. Systematic error can only be compensated, not MU You should not make any adjustments based on MU. It is an uncertainty not a correction factor (don’t get amused) Plain EMC may be still measuring a jello. But more accuracy is necessary in “Radio” certifications. It will be really odd if your measurements are +/- 4 dB off for the radiated power J MU is a nice tool if you know/want how to use it OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com mailto:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations http://www.ntscorp.com/about/locations From: lfresea...@aol.com mailto:lfresea...@aol.com [mailto:lfresea...@aol.com mailto:lfresea...@aol.com? ] Sent: Thursday, August 12, 2010 5:43 PM To: Deniz Demirci; b...@toprudder.com mailto:b...@toprudder.com ; emc-p...@ieee.org mailto:emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation Again, how do you guarantee / justify what you are doing if you don't care about the MU. I don't see how MU helps improve any measurement. How does it? Does it make the instrument magically more accurate? Does VSWR magically get lower? etc etc etc... No, it doesn't, nor will it ever. I'm amused to read you make adjustments for your MU being larger. Keep in mind were kind of measuring jello... I am strongly disagree with the “I did it and it is correct” attitude in EMC discipline. Maybe it explains the overall situation and measurement deviations between the laboratories Ironically, the studies... round robins etc that reported differences of 20 dB and up, included acredited labs, with MU budgets... So much for that. Quite simply, the only way for good consistent results is a good test technique, a competent operator, and good equipment. Please notice, MU is not mentioned here... Now, just for the record, I'm not being flippant. I prefer to focus where its worth the effort. I keep going back to measuring some limit, which I still maintain is somewhat arbitrary. If you fail by a few dB, so what... In real life you should be held accountable for your products performance. If you get calls because it malfunctions, then you don't have a good design. If you never get a call, then it's probably fine. We need to forget about MU and address the other low hanging fruit first... Sincerely, Derek Walton From: Deniz Demirci deniz.demi
Re: Calibration supplier for signal generator with pulse modulation
Hi Deniz, what entity is going to do something of little value unless forced to? Of course MU is done for auditing reasons. Very few tests require it in EMC.. Please do not bring up radio tests, I'm referring to EMC. Clause 5.4.1 states... .and, where appropriate, an estimation of the measurement uncertainty as well as statistical techniques for analysis of test and/or calibration data. If you are ASKED to do MU outside of this it's either because your assessing body is over zealous, or your assessor is uneducated. You must push back and say NO! Failure to do this is punishing your client, and more important the consumer, which includes me and I'm taxed enough already! I wouldn't consider myself a novice in MU, or EMC testing, but I can learn. That said, I have yet to see a genuine advantage for MU improving measurement. What does calculating MU have to do with quantifying accuracy? All it does is put windows about what you might be measuring. Now, here's a chance to back a stance by a fellow assessor who has campaigned for ( and I support his idea ) that ISO 17025 should be split into two documents: one for test, the other for calibration. I wholeheartedly support the addressing of MU in the calibration document, and there being NO mention in the test document. ( Dan, if your reading, these are my words not yours... ) Cheers, Derek. From: Deniz Demirci deniz.demi...@ntscorp.com To: lfresea...@aol.com; b...@toprudder.com; emc-p...@ieee.org Sent: Thu, Aug 12, 2010 7:59 pm Subject: RE: Calibration supplier for signal generator with pulse modulation If MU is only for audit purpose, it won’t help at all. If you are using MU for your benefit, there are always some improvement opportunities in your test setup. If you can’t quantify how inaccurate you are, how do you improve anything? quote I'm amused to read you make adjustments for your MU being larger. Keep in mind were kind of measuring jello.../quote Uncertainty and measurement errors are different. Systematic error can only be compensated, not MU You should not make any adjustments based on MU. It is an uncertainty not a correction factor (don’t get amused) Plain EMC may be still measuring a jello. But more accuracy is necessary in “Radio” certifications. It will be really odd if your measurements are +/- 4 dB off for the radiated power J MU is a nice tool if you know/want how to use it OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com mailto:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations http://www.ntscorp.com/about/locations From: lfresea...@aol.com [mailto:lfresea...@aol.com mailto:lfresea...@aol.com? ] Sent: Thursday, August 12, 2010 5:43 PM To: Deniz Demirci; b...@toprudder.com; emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation Again, how do you guarantee / justify what you are doing if you don't care about the MU. I don't see how MU helps improve any measurement. How does it? Does it make the instrument magically more accurate? Does VSWR magically get lower? etc etc etc... No, it doesn't, nor will it ever. I'm amused to read you make adjustments for your MU being larger. Keep in mind were kind of measuring jello... I am strongly disagree with the “I did it and it is correct” attitude in EMC discipline. Maybe it explains the overall situation and measurement deviations between the laboratories Ironically, the studies... round robins etc that reported differences of 20 dB and up, included acredited labs, with MU budgets... So much for that. Quite simply, the only way for good consistent results is a good test technique, a competent operator, and good equipment. Please notice, MU is not mentioned here... Now, just for the record, I'm not being flippant. I prefer to focus where its worth the effort. I keep going back to measuring some limit, which I still maintain is somewhat arbitrary. If you fail by a few dB, so what... In real life you should be held accountable for your products performance. If you get calls because it malfunctions, then you don't have a good design. If you never get a call, then it's probably fine. We need to forget about MU and address the other low hanging fruit first... Sincerely, Derek Walton From: Deniz Demirci deniz.demi...@ntscorp.com To: Bob Richards b...@toprudder.com; emc-p...@ieee.org Sent: Thu, Aug 12, 2010 2:51 pm Subject: RE: Calibration supplier for signal generator with pulse modulation I've been performing in-house calibrations of LNA's, LISN's, CDN's, Current clamps and they have been accepted by the auditors. There is no restriction in terms of 17025 if you follow the requirements such as dedicated calibration instrumentation and MEASUREMENT UNCERTAINTY assessment. I admit my MU figure for calibration is larger than a calibration
RE: Calibration supplier for signal generator with pulse modulation
If MU is only for audit purpose, it won’t help at all. If you are using MU for your benefit, there are always some improvement opportunities in your test setup. If you can’t quantify how inaccurate you are, how do you improve anything? quote I'm amused to read you make adjustments for your MU being larger. Keep in mind were kind of measuring jello.../quote Uncertainty and measurement errors are different. Systematic error can only be compensated, not MU You should not make any adjustments based on MU. It is an uncertainty not a correction factor (don’t get amused) Plain EMC may be still measuring a jello. But more accuracy is necessary in “Radio” certifications. It will be really odd if your measurements are +/- 4 dB off for the radiated power J MU is a nice tool if you know/want how to use it OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com mailto:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations http://www.ntscorp.com/about/locations From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Thursday, August 12, 2010 5:43 PM To: Deniz Demirci; b...@toprudder.com; emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation Again, how do you guarantee / justify what you are doing if you don't care about the MU. I don't see how MU helps improve any measurement. How does it? Does it make the instrument magically more accurate? Does VSWR magically get lower? etc etc etc... No, it doesn't, nor will it ever. I'm amused to read you make adjustments for your MU being larger. Keep in mind were kind of measuring jello... I am strongly disagree with the “I did it and it is correct” attitude in EMC discipline. Maybe it explains the overall situation and measurement deviations between the laboratories Ironically, the studies... round robins etc that reported differences of 20 dB and up, included acredited labs, with MU budgets... So much for that. Quite simply, the only way for good consistent results is a good test technique, a competent operator, and good equipment. Please notice, MU is not mentioned here... Now, just for the record, I'm not being flippant. I prefer to focus where its worth the effort. I keep going back to measuring some limit, which I still maintain is somewhat arbitrary. If you fail by a few dB, so what... In real life you should be held accountable for your products performance. If you get calls because it malfunctions, then you don't have a good design. If you never get a call, then it's probably fine. We need to forget about MU and address the other low hanging fruit first... Sincerely, Derek Walton From: Deniz Demirci deniz.demi...@ntscorp.com To: Bob Richards b...@toprudder.com; emc-p...@ieee.org Sent: Thu, Aug 12, 2010 2:51 pm Subject: RE: Calibration supplier for signal generator with pulse modulation I've been performing in-house calibrations of LNA's, LISN's, CDN's, Current clamps and they have been accepted by the auditors. There is no restriction in terms of 17025 if you follow the requirements such as dedicated calibration instrumentation and MEASUREMENT UNCERTAINTY assessment. I admit my MU figure for calibration is larger than a calibration laboratory and it is accounted in EMC measurements. Again, how do you guarantee / justify what you are doing if you don't care about the MU. I am strongly disagree with the “I did it and it is correct” attitude in EMC discipline. Maybe it explains the overall situation and measurement deviations between the laboratories OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations From: emc-p...@ieee.org on behalf of Bob Richards Sent: Thu 8/12/2010 7:51 AM To: emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation --- On Thu, 8/12/10, Ken Javor ken.ja...@emccompliance.com wrote: And similarly, not because of MU but because of 17025 or perhaps ISO 9000, I've seen test equipment that could easily have been calibrated in house, such as current probes, LISNs and a 41 inch rod antenna have to be sent to the calibration lab. This is totally unproductive, except for the calibration lab. And I would argue further that it is detrimental to the discipline, because if you do your own calibration, you understand better how things work. This is a subject near to my heart. I've performed in-house calibrations of cables, LISNs, CDNs, current probes etc, and I agree 100% with what you said. Knowing the procedure helps to understand how things work and, just as important, gives a person the knowledge of how to perform quick verifications of a test setup in case there is ever any question
Re: Calibration supplier for signal generator with pulse modulation
Again, how do you guarantee / justify what you are doing if you don't care about the MU. I don't see how MU helps improve any measurement. How does it? Does it make the instrument magically more accurate? Does VSWR magically get lower? etc etc etc... No, it doesn't, nor will it ever. I'm amused to read you make adjustments for your MU being larger. Keep in mind were kind of measuring jello... I am strongly disagree with the “I did it and it is correct” attitude in EMC discipline. Maybe it explains the overall situation and measurement deviations between the laboratories Ironically, the studies... round robins etc that reported differences of 20 dB and up, included acredited labs, with MU budgets... So much for that. Quite simply, the only way for good consistent results is a good test technique, a competent operator, and good equipment. Please notice, MU is not mentioned here... Now, just for the record, I'm not being flippant. I prefer to focus where its worth the effort. I keep going back to measuring some limit, which I still maintain is somewhat arbitrary. If you fail by a few dB, so what... In real life you should be held accountable for your products performance. If you get calls because it malfunctions, then you don't have a good design. If you never get a call, then it's probably fine. We need to forget about MU and address the other low hanging fruit first... Sincerely, Derek Walton From: Deniz Demirci deniz.demi...@ntscorp.com To: Bob Richards b...@toprudder.com; emc-p...@ieee.org Sent: Thu, Aug 12, 2010 2:51 pm Subject: RE: Calibration supplier for signal generator with pulse modulation I've been performing in-house calibrations of LNA's, LISN's, CDN's, Current clamps and they have been accepted by the auditors. There is no restriction in terms of 17025 if you follow the requirements such as dedicated calibration instrumentation and MEASUREMENT UNCERTAINTY assessment. I admit my MU figure for calibration is larger than a calibration laboratory and it is accounted in EMC measurements. Again, how do you guarantee / justify what you are doing if you don't care about the MU. I am strongly disagree with the “I did it and it is correct” attitude in EMC discipline. Maybe it explains the overall situation and measurement deviations between the laboratories OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations From: emc-p...@ieee.org on behalf of Bob Richards Sent: Thu 8/12/2010 7:51 AM To: emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation --- On Thu, 8/12/10, Ken Javor ken.ja...@emccompliance.com wrote: And similarly, not because of MU but because of 17025 or perhaps ISO 9000, I've seen test equipment that could easily have been calibrated in house, such as current probes, LISNs and a 41 inch rod antenna have to be sent to the calibration lab. This is totally unproductive, except for the calibration lab. And I would argue further that it is detrimental to the discipline, because if you do your own calibration, you understand better how things work. This is a subject near to my heart. I've performed in-house calibrations of cables, LISNs, CDNs, current probes etc, and I agree 100% with what you said. Knowing the procedure helps to understand how things work and, just as important, gives a person the knowledge of how to perform quick verifications of a test setup in case there is ever any question as to the proper operation of that equipment. Every so often, a conversation comes up in the lab about whether we should do in-house calibrations. The issue is never about MU, cost or validity of data, it usually hinges around 17025 and what auditors will say. IMHO, shipping LISNs and/or CDNs to have calibrations performed by a cal lab is less reliable than in-house calibrations. This has little to do with the cal lab's ability, but from the possibility of damage during shipping. I've had CDNs come back with stuff rattling around inside (possibly chips off of ferrites?). If I can't perform an impedance verification in house, then what should I do to insure it is not damaged - send it back to the cal lab? Bob R. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy
RE: Calibration supplier for signal generator with pulse modulation
I've been performing in-house calibrations of LNA's, LISN's, CDN's, Current clamps and they have been accepted by the auditors. There is no restriction in terms of 17025 if you follow the requirements such as dedicated calibration instrumentation and MEASUREMENT UNCERTAINTY assessment. I admit my MU figure for calibration is larger than a calibration laboratory and it is accounted in EMC measurements. Again, how do you guarantee / justify what you are doing if you don't care about the MU. I am strongly disagree with the I did it and it is correct attitude in EMC discipline. Maybe it explains the overall situation and measurement deviations between the laboratories OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations From: emc-p...@ieee.org on behalf of Bob Richards Sent: Thu 8/12/2010 7:51 AM To: emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation --- On Thu, 8/12/10, Ken Javor ken.ja...@emccompliance.com wrote: And similarly, not because of MU but because of 17025 or perhaps ISO 9000, I've seen test equipment that could easily have been calibrated in house, such as current probes, LISNs and a 41 inch rod antenna have to be sent to the calibration lab. This is totally unproductive, except for the calibration lab. And I would argue further that it is detrimental to the discipline, because if you do your own calibration, you understand better how things work. This is a subject near to my heart. I've performed in-house calibrations of cables, LISNs, CDNs, current probes etc, and I agree 100% with what you said. Knowing the procedure helps to understand how things work and, just as important, gives a person the knowledge of how to perform quick verifications of a test setup in case there is ever any question as to the proper operation of that equipment. Every so often, a conversation comes up in the lab about whether we should do in-house calibrations. The issue is never about MU, cost or validity of data, it usually hinges around 17025 and what auditors will say. IMHO, shipping LISNs and/or CDNs to have calibrations performed by a cal lab is less reliable than in-house calibrations. This has little to do with the cal lab's ability, but from the possibility of damage during shipping. I've had CDNs come back with stuff rattling around inside (possibly chips off of ferrites?). If I can't perform an impedance verification in house, then what should I do to insure it is not damaged - send it back to the cal lab? Bob R. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
--- On Thu, 8/12/10, Ken Javor ken.ja...@emccompliance.com wrote: And similarly, not because of MU but because of 17025 or perhaps ISO 9000, I’ve seen test equipment that could easily have been calibrated in house, such as current probes, LISNs and a 41 inch rod antenna have to be sent to the calibration lab. This is totally unproductive, except for the calibration lab. And I would argue further that it is detrimental to the discipline, because if you do your own calibration, you understand better how things work. This is a subject near to my heart. I've performed in-house calibrations of cables, LISNs, CDNs, current probes etc, and I agree 100% with what you said. Knowing the procedure helps to understand how things work and, just as important, gives a person the knowledge of how to perform quick verifications of a test setup in case there is ever any question as to the proper operation of that equipment. Every so often, a conversation comes up in the lab about whether we should do in-house calibrations. The issue is never about MU, cost or validity of data, it usually hinges around 17025 and what auditors will say. IMHO, shipping LISNs and/or CDNs to have calibrations performed by a cal lab is less reliable than in-house calibrations. This has little to do with the cal lab's ability, but from the possibility of damage during shipping. I've had CDNs come back with stuff rattling around inside (possibly chips off of ferrites?). If I can't perform an impedance verification in house, then what should I do to insure it is not damaged - send it back to the cal lab? Bob R. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
Well said Ken. A check of VSWR to check that the antenna's not been damaged (including horn antennas I guess) should be good enough to check for any overstress or mechanical damage (I have come across loose screws in bicon antennas). If it hasn't changed, then the antenna factor hasn't changed. In fact, if this was allowed as a calibration - I'm sure it would get done more often than the off-site calibration. Luke Turnbull On 12/08/2010 at 14:30, in message c88961b2.8480c%ken.ja...@emccompliance.com, Ken Javor ken.ja...@emccompliance.com wrote: And similarly, not because of MU but because of 17025 or perhaps ISO 9000, I’ve seen test equipment that could easily have been calibrated in house, such as current probes, LISNs and a 41 inch rod antenna have to be sent to the calibration lab. This is totally unproductive, except for the calibration lab. And I would argue further that it is detrimental to the discipline, because if you do your own calibration, you understand better how things work. Oh, and my favorite, the calibration of microwave horn antennas, whose properties are entirely set by their linear dimensions. The measurement or verification that their dimensions have not changed since their original acquisition is so much more accurate than the direct measurement of their gain. In fact any passive antenna used in the EMI measurement business can be easily checked visually for dimensional abnormalities, and those with a balun, such as a dipole, biconical or logperiodic can be checked for vswr using a directional coupler; no need for expensive and time consuming annual or semi-annual trips to a calibration facility. If it isn’t physically damaged, and the vswr meets original specs, meaning the balun is good, the antenna is good. Ken Javor Phone: (256) 650-5261 From: Cortland Richmond k...@earthlink.net Reply-To: k...@earthlink.net List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thu, 12 Aug 2010 07:24:17 -0400 To: emc-pstc emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation A tangential issue: those who rely on that algorithmic process often don't know why certain things are required and others left unsaid. I've see a manager forbid using a high-pass filter during CE testing because it appeared nowhere in a standard's setup drawings. Demonstration was required! Cortland KA5S - Original Message - From: Ken Javor mailto:ken.ja...@emccompliance.com mailto:ken.ja...@emccompliance.com To: Untitled mailto:emc-p...@ieee.org mailto:emc-p...@ieee.org Sent: 8/11/2010 1:04:51 PM Subject: Re: Calibration supplier for signal generator with pulse modulation Bingo. Clearly another driver for inserting MU where it doesn't belong is a desire to replace the need for competent personnel with an algorithmic process that works for any personnel. But the same personnel who don‚t know how to properly perform the test will also not know how to run the algorithm. Hence Mr. Walton‚s observations on how poorly MU is executed in reality. Ken Javor Phone: (256) 650-5261 From: Dennis Ward dw...@atcb.com Reply-To: dw...@atcb.com Date: Wed, 11 Aug 2010 09:50:21 -0700 To: lfresea...@aol.com, deniz.demi...@ntscorp.com, emc-p...@ieee.org Subject: RE: Calibration supplier for signal generator with pulse modulation I think I would only add that while measurement uncertainties for EMC is nebulous at best, at the same time we do not want to get into the habit of a slam dunk mentality of Œoh, just a number, it doesn‚t matter.‰ That is why Derek‚s statement of „What‚s really needed is a competent individual with adequate equipment‰ is so important. Where electromagnetic compatibility is concerned, competence of the engineers doing the measurement is probably much more importa! nt than uncertainties. I know that one of the biggest benefits to testing in the radio approvals industry is competence of test personnel. Compliance does matter and the best way to keep unneeded uncertainties out of the EMC measurement industry, is to keep competence of test personnel in. Dennis Ward Director of Engineering American TCB Certification Resource for the Wireless Industry www.atcb.com http://www.atcb.com/ http://www.atcb.com/ 703-847-4700 fax 703-847-6888 direct - 703-880-4841 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings
Re: Calibration supplier for signal generator with pulse modulation
And similarly, not because of MU but because of 17025 or perhaps ISO 9000, I’ve seen test equipment that could easily have been calibrated in house, such as current probes, LISNs and a 41 inch rod antenna have to be sent to the calibration lab. This is totally unproductive, except for the calibration lab. And I would argue further that it is detrimental to the discipline, because if you do your own calibration, you understand better how things work. Oh, and my favorite, the calibration of microwave horn antennas, whose properties are entirely set by their linear dimensions. The measurement or verification that their dimensions have not changed since their original acquisition is so much more accurate than the direct measurement of their gain. In fact any passive antenna used in the EMI measurement business can be easily checked visually for dimensional abnormalities, and those with a balun, such as a dipole, biconical or logperiodic can be checked for vswr using a directional coupler; no need for expensive and time consuming annual or semi-annual trips to a calibration facility. If it isn’t physically damaged, and the vswr meets original specs, meaning the balun is good, the antenna is good. Ken Javor Phone: (256) 650-5261 From: Cortland Richmond k...@earthlink.net Reply-To: k...@earthlink.net List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thu, 12 Aug 2010 07:24:17 -0400 To: emc-pstc emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation A tangential issue: those who rely on that algorithmic process often don't know why certain things are required and others left unsaid. I've see a manager forbid using a high-pass filter during CE testing because it appeared nowhere in a standard's setup drawings. Demonstration was required! Cortland KA5S - Original Message - From: Ken Javor mailto:ken.ja...@emccompliance.com mailto:ken.ja...@emccompliance.com To: Untitled mailto:emc-p...@ieee.org mailto:emc-p...@ieee.org Sent: 8/11/2010 1:04:51 PM Subject: Re: Calibration supplier for signal generator with pulse modulation Bingo. Clearly another driver for inserting MU where it doesn't belong is a desire to replace the need for competent personnel with an algorithmic process that works for any personnel. But the same personnel who don‚t know how to properly perform the test will also not know how to run the algorithm. Hence Mr. Walton‚s observations on how poorly MU is executed in reality. Ken Javor Phone: (256) 650-5261 From: Dennis Ward dw...@atcb.com Reply-To: dw...@atcb.com Date: Wed, 11 Aug 2010 09:50:21 -0700 To: lfresea...@aol.com, deniz.demi...@ntscorp.com, emc-p...@ieee.org Subject: RE: Calibration supplier for signal generator with pulse modulation I think I would only add that while measurement uncertainties for EMC is nebulous at best, at the same time we do not want to get into the habit of a slam dunk mentality of Œoh, just a number, it doesn‚t matter.‰ That is why Derek‚s statement of „What‚s really needed is a competent individual with adequate equipment‰ is so important. Where electromagnetic compatibility is concerned, competence of the engineers doing the measurement is probably much more importa! nt than uncertainties. I know that one of the biggest benefits to testing in the radio approvals industry is competence of test personnel. Compliance does matter and the best way to keep unneeded uncertainties out of the EMC measurement industry, is to keep competence of test personnel in. Dennis Ward Director of Engineering American TCB Certification Resource for the Wireless Industry www.atcb.com http://www.atcb.com/ http://www.atcb.com/ 703-847-4700 fax 703-847-6888 direct - 703-880-4841 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com - This message is from
Re: Calibration supplier for signal generator with pulse modulation
A tangential issue: those who rely on that algorithmic process often don't know why certain things are required and others left unsaid. I've see a manager forbid using a high-pass filter during CE testing because it appeared nowhere in a standard's setup drawings. Demonstration was required! Cortland KA5S - Original Message - From: Ken Javor mailto:ken.ja...@emccompliance.com To: Untitled mailto:emc-p...@ieee.org Sent: 8/11/2010 1:04:51 PM Subject: Re: Calibration supplier for signal generator with pulse modulation Bingo. Clearly another driver for inserting MU where it doesn't belong is a desire to replace the need for competent personnel with an algorithmic process that works for any personnel. But the same personnel who don’t know how to properly perform the test will also not know how to run the algorithm. Hence Mr. Walton’s observations on how poorly MU is executed in reality. Ken Javor Phone: (256) 650-5261 From: Dennis Ward dw...@atcb.com Reply-To: dw...@atcb.com Date: Wed, 11 Aug 2010 09:50:21 -0700 To: lfresea...@aol.com, deniz.demi...@ntscorp.com, emc-p...@ieee.org Subject: RE: Calibration supplier for signal generator with pulse modulation I think I would only add that while measurement uncertainties for EMC is nebulous at best, at the same time we do not want to get into the habit of a slam dunk mentality of ‘oh, just a number, it doesn’t matter.” That is why Derek’s statement of “What’s really needed is a competent individual with adequate equipment” is so important. Where electromagnetic compatibility is concerned, competence of the engineers doing the measurement is probably much more importa! nt than uncertainties. I know that one of the biggest benefits to testing in the radio approvals industry is competence of test personnel. Compliance does matter and the best way to keep unneeded uncertainties out of the EMC measurement industry, is to keep competence of test personnel in. Dennis Ward Director of Engineering American TCB Certification Resource for the Wireless Industry www.atcb.com http://www.atcb.com/ http://www.atcb.com/ 703-847-4700 fax 703-847-6888 direct - 703-880-4841 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
And of course note that for radiated measurements there is no control on room accuracy effects outside of minimum room dimensions, and minimum absorber coverage and minimum absorber attenuation (as specified by manufacturer, not as measured installed). HOWEVER, also note that EMI qualification in the military, aerospace and automotive world is not the proof of the pudding. In all these areas, the final product (integrated platform) is checked for electromagnetic compatibility, i.e., it undergoes an EMC test. A military EMC test often includes a spectrum analyzer survey of the noise coupled into platform antennas at frequencies where subsystems failed radiated emission requirements. That test is the ultimate high accuracy EMC test: it checks the potential for rfi in precisely the configuration the integrated system will be used. The spectrum analyzer survey and the larger EMC test are the proof of the pudding. Note the difference between EMI qualification testing which is quantitative in nature, and EMC testing which is part qualitative and part quantitative (spectrum analyzer survey). In any case, people in the military, aerospace and automotive businesses know the difference between EMI and EMC testing. The distinction seems to be lost on the commercial world, where an EMI qualification test is almost always refereed to as an EMC test. Ken Javor Phone: (256) 650-5261 From: Cortland Richmond k...@earthlink.net Reply-To: k...@earthlink.net Date: Wed, 11 Aug 2010 22:02:17 -0400 To: emc-pstc emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation MIL-STD 461E does not usually ask we be particularly accurate, merely sufficient. QUOTE 4.3.1 Measurement tolerances. Unless otherwise stated for a particular measurement, the tolerance shall be as follows: a. Distance: ±5% b. Frequency: ±2% c. Amplitude, measurement receiver: ±2 dB d. Amplitude, measurement system (includes measurement receivers, transducers, cables, and so forth): ±3 dB e. Time (waveforms): ±5% f. Resistors: ±5% e. Capacitors: ±20% END QUOTE Also note: QUOTE 4.3.10.4.2 Modulation of susceptibility signals. Susceptibility test signals for CS114 and RS103 shall be pulse modulated (on/off ratio of 40 dB minimum) at a 1 kHz rate with a 50% duty cycle. END QUOTE On the civilian side, some years ago I was at a test lab I won't identify, and asked if we really had 80 percent modulation. Sure, we did; there was one volt of audio going into the SG external moduation jack and the generator was set for 80 percent. After a little griping they let me look on the SA. THEN they hauled out the 'scope. They were into both positive and negative peak clipping. Some things you HAVE to check. (PS: We still didn't pass.) Cortland KA5S [Original Message] From: Ken Javor ken.ja...@emccompliance.com To: Untitled emc-p...@ieee.org Date: 8/11/2010 1:03:09 PM Subject: Re: Calibration supplier for signal generator with pulse modulation This gets back to Mr. Walton's differentiation between EMI testing and calibration laboratories. Clearly modulation, measured with an o'scope, can be measured to the tolerances available from the o'scope. That's plenty good enough. It strains credulity that there is one brand of scope that would give sloppier results making it easier to pass a test. The essence of what Mr. Walton and I are saying is well-expressed by the rules for using significant digits: You don't get four digit accuracy as the result of computations using two digit accuracy inputs. EMI limits are quite arbitrary; trying to meet them with accuracy exceeding the limit placement process is unnecessary. As stated earlier, the only reason for MU control is on the basic facility chambers/OATS so that there is some repeatability from facility to facility, and so that it isn't easier to pass at one facility than another. Anything beyond that is superfluous and an unnecessary expense. Regarding the example of the cable at 10 GHz. The MIL-STD-461 measurement system integrity check does indeed check that the cable is properly accounted for in terms of attenuation. Mr. Demirci is correct that the signal generator can be expected to be a better match to the cable than is the actual antenna used. However, to the limits of accuracy required for EMI testing, the antenna factor calibration takes care of the mismatch between antenna and cable, since the antenna is calibrated in a 50 Ohm system (albeit likely using pads between antenna and cable for calibration). If further accuracy is desired, most manufacturers provide vswr characteristics for their antennas. Fear isn't the issue. The issue is a misapplication of a process where it isn't required, and the patina of precision and accuracy this dishonestly bestows on an inherently inaccurate and imprecise discipline. Ken Javor Phone: (256) 650-5261 From: Deniz
Re: Calibration supplier for signal generator with pulse modulation
The MIL-STD-461 requirement to show 1% resolution is usually interpreted to apply to outage conditions only. If you had a plot from dc to daylight that was under the limit, it could be plotted on 8.5 x 11 paper (or electronic equivalent) and that would work just fine. Even if there outages present, if they were listed numerically on another page with sufficient resolution, that would work as well. Ken Javor Phone: (256) 650-5261 From: Cortland Richmond k...@earthlink.net Reply-To: k...@earthlink.net Date: Wed, 11 Aug 2010 22:15:00 -0400 To: Sundstrom, Michael michael_sundst...@overheaddoor.com, emc-pstc emc-p...@ieee.org Subject: RE: Calibration supplier for signal generator with pulse modulation I don't have the manual here at home, but a standard I DL'd I at work -- and I had to hunt for it -- asks (should) equipment be calibrated with a signal of four times the accuracy specified for the device in question. If that accuracy is unattainable, it requires justification be added and a note in the calibration documents be added regarding the accuracy the calibrated test equipment is good for, regardless of its specifications. Given MIL-STD-461's generous accuracy requirements, that can't be hard to live with. (What I wonder about are requirements one be able to read 1% on a printed plot!) Cortland KA5S [Original Message] From: Sundstrom, Michael michael_sundst...@overheaddoor.com To: Ken Javor ken.ja...@emccompliance.com; EMC-PSTC@LISTSERV.IEEE.ORG EMC-PSTC@LISTSERV.IEEE.ORG Date: 8/11/2010 1:25:38 PM Subject: RE: Calibration supplier for signal generator with pulse modulation Ken / Deniz, Speaking of significant digit's: I'm still looking for that EMI receiver that will measure to 1/100 of a dB. So I can report to a 1/10 of a dB in reports like I'm asked to. Michael Sundstrom OHD / TREQ Dallas Electronic Lab Analist, EMC Lead 2170 French Settelment Rd, Suite B Dallas, Texas 75212 (214) 579 6312 -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Wednesday, August 11, 2010 11:59 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Calibration supplier for signal generator with pulse modulation This gets back to Mr. Walton's differentiation between EMI testing and calibration laboratories. Clearly modulation, measured with an o'scope, can be measured to the tolerances available from the o'scope. That's plenty good enough. It strains credulity that there is one brand of scope that would give sloppier results making it easier to pass a test. The essence of what Mr. Walton and I are saying is well-expressed by the rules for using significant digits: You don't get four digit accuracy as the result of computations using two digit accuracy inputs. EMI limits are quite arbitrary; trying to meet them with accuracy exceeding the limit placement process is unnecessary. As stated earlier, the only reason for MU control is on the basic facility chambers/OATS so that there is some repeatability from facility to facility, and so that it isn't easier to pass at one facility than another. Anything beyond that is superfluous and an unnecessary expense. Regarding the example of the cable at 10 GHz. The MIL-STD-461 measurement system integrity check does indeed check that the cable is properly accounted for in terms of attenuation. Mr. Demirci is correct that the signal generator can be expected to be a better match to the cable than is the actual antenna used. However, to the limits of accuracy required for EMI testing, the antenna factor calibration takes care of the mismatch between antenna and cable, since the antenna is calibrated in a 50 Ohm system (albeit likely using pads between antenna and cable for calibration). If further accuracy is desired, most manufacturers provide vswr characteristics for their antennas. Fear isn't the issue. The issue is a misapplication of a process where it isn't required, and the patina of precision and accuracy this dishonestly bestows on an inherently inaccurate and imprecise discipline. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com Date: Wed, 11 Aug 2010 08:35:06 -0700 To: Untitled emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation. Is your tolerance 0.1 % or between 60 % to 90 % is good enough. There is more than a dB peak difference in the signal for 60 % AM and 80 % AM modulations. You won't realize the difference with a field probe in radiated immunity tests with modulated signal. (Simple math; 20*Log(1.6/1.8) = -1.02 dB) It seems not very insignificant to me Another case; If you are using 6 meter cable
RE: Calibration supplier for signal generator with pulse modulation
I don't have the manual here at home, but a standard I DL'd I at work -- and I had to hunt for it -- asks (should) equipment be calibrated with a signal of four times the accuracy specified for the device in question. If that accuracy is unattainable, it requires justification be added and a note in the calibration documents be added regarding the accuracy the calibrated test equipment is good for, regardless of its specifications. Given MIL-STD-461's generous accuracy requirements, that can't be hard to live with. (What I wonder about are requirements one be able to read 1% on a printed plot!) Cortland KA5S [Original Message] From: Sundstrom, Michael michael_sundst...@overheaddoor.com To: Ken Javor ken.ja...@emccompliance.com; EMC-PSTC@LISTSERV.IEEE.ORG EMC-PSTC@LISTSERV.IEEE.ORG Date: 8/11/2010 1:25:38 PM Subject: RE: Calibration supplier for signal generator with pulse modulation Ken / Deniz, Speaking of significant digit's: I'm still looking for that EMI receiver that will measure to 1/100 of a dB. So I can report to a 1/10 of a dB in reports like I'm asked to. Michael Sundstrom OHD / TREQ Dallas Electronic Lab Analist, EMC Lead 2170 French Settelment Rd, Suite B Dallas, Texas 75212 (214) 579 6312 -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Wednesday, August 11, 2010 11:59 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Calibration supplier for signal generator with pulse modulation This gets back to Mr. Walton's differentiation between EMI testing and calibration laboratories. Clearly modulation, measured with an o'scope, can be measured to the tolerances available from the o'scope. That's plenty good enough. It strains credulity that there is one brand of scope that would give sloppier results making it easier to pass a test. The essence of what Mr. Walton and I are saying is well-expressed by the rules for using significant digits: You don't get four digit accuracy as the result of computations using two digit accuracy inputs. EMI limits are quite arbitrary; trying to meet them with accuracy exceeding the limit placement process is unnecessary. As stated earlier, the only reason for MU control is on the basic facility chambers/OATS so that there is some repeatability from facility to facility, and so that it isn't easier to pass at one facility than another. Anything beyond that is superfluous and an unnecessary expense. Regarding the example of the cable at 10 GHz. The MIL-STD-461 measurement system integrity check does indeed check that the cable is properly accounted for in terms of attenuation. Mr. Demirci is correct that the signal generator can be expected to be a better match to the cable than is the actual antenna used. However, to the limits of accuracy required for EMI testing, the antenna factor calibration takes care of the mismatch between antenna and cable, since the antenna is calibrated in a 50 Ohm system (albeit likely using pads between antenna and cable for calibration). If further accuracy is desired, most manufacturers provide vswr characteristics for their antennas. Fear isn't the issue. The issue is a misapplication of a process where it isn't required, and the patina of precision and accuracy this dishonestly bestows on an inherently inaccurate and imprecise discipline. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com Date: Wed, 11 Aug 2010 08:35:06 -0700 To: Untitled emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation. Is your tolerance 0.1 % or between 60 % to 90 % is good enough. There is more than a dB peak difference in the signal for 60 % AM and 80 % AM modulations. You won't realize the difference with a field probe in radiated immunity tests with modulated signal. (Simple math; 20*Log(1.6/1.8) = -1.02 dB) It seems not very insignificant to me Another case; If you are using 6 meter cable for radiated emission at 10 GHz, your cable characterization uncertainty is more than 1.5 dB even with a quite high grade cable (Experimental measurements). Check the cable vswr figures in their specs measured in ideal conditions. Even a simple cable is a significant uncertainty contributor. Your measurement antenna is not exactly 50 Ohm at 10 GHz also. Site imperfection is another story. Those figures are not accounted for in the MIL-STD-461 RE102 verification. Everything seems to be very good when you terminate the measurement cable with a signal generator (50 ohm) output. I don't agree with this quote an ultimate proof-of-the-pudding, /quote You can use all your engineering skills for the tests but you have
Re: Calibration supplier for signal generator with pulse modulation
MIL-STD 461E does not usually ask we be particularly accurate, merely sufficient. QUOTE 4.3.1 Measurement tolerances. Unless otherwise stated for a particular measurement, the tolerance shall be as follows: a. Distance: 15% b. Frequency: 12% c. Amplitude, measurement receiver: 12 dB d. Amplitude, measurement system (includes measurement receivers, transducers, cables, and so forth): 13 dB e. Time (waveforms): 15% f. Resistors: 15% e. Capacitors: 120% END QUOTE Also note: QUOTE 4.3.10.4.2 Modulation of susceptibility signals. Susceptibility test signals for CS114 and RS103 shall be pulse modulated (on/off ratio of 40 dB minimum) at a 1 kHz rate with a 50% duty cycle. END QUOTE On the civilian side, some years ago I was at a test lab I won't identify, and asked if we really had 80 percent modulation. Sure, we did; there was one volt of audio going into the SG external moduation jack and the generator was set for 80 percent. After a little griping they let me look on the SA. THEN they hauled out the 'scope. They were into both positive and negative peak clipping. Some things you HAVE to check. (PS: We still didn't pass.) Cortland KA5S [Original Message] From: Ken Javor ken.ja...@emccompliance.com To: Untitled emc-p...@ieee.org Date: 8/11/2010 1:03:09 PM Subject: Re: Calibration supplier for signal generator with pulse modulation This gets back to Mr. Walton's differentiation between EMI testing and calibration laboratories. Clearly modulation, measured with an o'scope, can be measured to the tolerances available from the o'scope. That's plenty good enough. It strains credulity that there is one brand of scope that would give sloppier results making it easier to pass a test. The essence of what Mr. Walton and I are saying is well-expressed by the rules for using significant digits: You don't get four digit accuracy as the result of computations using two digit accuracy inputs. EMI limits are quite arbitrary; trying to meet them with accuracy exceeding the limit placement process is unnecessary. As stated earlier, the only reason for MU control is on the basic facility chambers/OATS so that there is some repeatability from facility to facility, and so that it isn't easier to pass at one facility than another. Anything beyond that is superfluous and an unnecessary expense. Regarding the example of the cable at 10 GHz. The MIL-STD-461 measurement system integrity check does indeed check that the cable is properly accounted for in terms of attenuation. Mr. Demirci is correct that the signal generator can be expected to be a better match to the cable than is the actual antenna used. However, to the limits of accuracy required for EMI testing, the antenna factor calibration takes care of the mismatch between antenna and cable, since the antenna is calibrated in a 50 Ohm system (albeit likely using pads between antenna and cable for calibration). If further accuracy is desired, most manufacturers provide vswr characteristics for their antennas. Fear isn't the issue. The issue is a misapplication of a process where it isn't required, and the patina of precision and accuracy this dishonestly bestows on an inherently inaccurate and imprecise discipline. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com Date: Wed, 11 Aug 2010 08:35:06 -0700 To: Untitled emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation. Is your tolerance 0.1 % or between 60 % to 90 % is good enough. There is more than a dB peak difference in the signal for 60 % AM and 80 % AM modulations. You won't realize the difference with a field probe in radiated immunity tests with modulated signal. (Simple math; 20*Log(1.6/1.8) = -1.02 dB) It seems not very insignificant to me Another case; If you are using 6 meter cable for radiated emission at 10 GHz, your cable characterization uncertainty is more than 1.5 dB even with a quite high grade cable (Experimental measurements). Check the cable vswr figures in their specs measured in ideal conditions. Even a simple cable is a significant uncertainty contributor. Your measurement antenna is not exactly 50 Ohm at 10 GHz also. Site imperfection is another story. Those figures are not accounted for in the MIL-STD-461 RE102 verification. Everything seems to be very good when you terminate the measurement cable with a signal generator (50 ohm) output. I don't agree with this quote an ultimate proof-of-the-pudding, /quote You can use all your engineering skills for the tests but you have to quantify your risk using type B measurement uncertainty analysis and do the Type A if you can afford to see where you stand
RE: Calibration supplier for signal generator with pulse modulation
The one and only reason why EMI is “ not precise”, or “uncertain” is exactly one piece of equipment in the measurement chain…. The EUT and it’s physical set-up. *All* other aspects can very well and relatively easy be controlled under a MU system, allowing customers to compare quality and performance of different labs and and judge and compare the quality of measurement alternatives. Defining a MU figure also implies that a round robin test using a well defined EUT will get identical results everywhere +/- the margin defined by the labs uncertainty figure. It also makes it possible by accurately reproducing a real EUT setup in another lab to get comparable results. I agree that this round robin test is not the definition of daily EMI work. In real life you WILL have an undefined EUT with as many degrees of freedom of operation and setup as you can recognize, resulting in an uncertainty well beyond the MU figures this discussion is about. But that is no reason to neglect the accuracy specifications of the defined chain. There is also an additional skill required in EMI work, that is finding and characterizing cause of emissions or lack of immunity. Often a lack of EMC is caused by a loophole in the design, and a simple fix may virtually make the emissions disappear to such a degree that discussions about a few dB seem ridiculous. That is real engineering work and should not be confused with the art of measuring for which MU is meant. In Europe the EMC requirements (read limits) in the standards have been raised to an importance level (not by the European Commission but by the market stakeholders united in CENELEC/ISO/IEC) where an excess of 0.1 dB can make the difference between pass/fail and market-access or no-market-access. Hence a decision of enormous economic value. Lab shopping has been a popular method to gain access for equipment that marginally failed. An unwanted situation that disturbs a level playing field. That is why the EMC labs have been brought under the regime of ISO 17025 (also a market driven standard) and metrology entered the labs to force them to create reproducible measurements . Metrology assessors never saw an EUT and do not understand the EMI measurement chain. And if you are used to calibrate VOLTS and meters (SI ), the V/m do not seem so very different. So they imposed their methods upon us. And for each of the parts they recognized, they imposed us to make a MU. How right they were and how wrong they are. But one part cannot be subject to metrology methods: the EUT. (never available when an audit is made) But that does not imply that you cannot gain in quality and performance by applying a relatively simple procedure to the inaccuracy figures your equipment providers supply you with. And it makes you think about the impact of all components in the chain that affect accuracy. But that is not the only thing to be said about EMC , as Derek emphasizes. Gert Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens lfresea...@aol.com Verzonden: woensdag 11 augustus 2010 18:00 Aan: deniz.demi...@ntscorp.com; emc-p...@ieee.org Onderwerp: Re: Calibration supplier for signal generator with pulse modulation Hi Deniz, this is where real EMI guys differ from Metrology guys. We really don't need to be piddling with little numbers with the exception of frequency. Most of these modulations are compromises, and measuring a compromise accurately is a silly thing to do: in reality. You may want to get on board with the proof of the pudding phrase, it's OK in EMI: otherwise we expend all sorts of effort for no VALUE in return. The compliance world is obsessed with meeting a number, when the REAL reason for doing this testing is to ensure successful operation in use. I strongly disagree with Gerts statement MU is simple, it's not. Of the 140+ labs I've visited as an assessor, only a handful have a valid effort, and less than 1/2 doz believe it was of real value. Precision and EMI do not go together. I for one like it like that. Whats really needed is a competent individual with adequate equipment. If a committee would like MU, then as test labs we should isolate the cost that adds, and identify it on peoples invoices when that test is run. It's an effective way of making the standard unpopular. The reason I'm on a soap box about this is because unless silly requiremnts like this re CHALLENGED, and not just carte-blanche accepted, they become requirements. For calibration, I believe MU is useful, but for EMI, it has no place. Sincerely, Derek. From: Deniz Demirci deniz.demi...@ntscorp.com To: Untitled emc-p...@ieee.org Sent: Wed, Aug 11, 2010 10:35 am Subject: RE: Calibration supplier for signal generator with pulse modulation Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation
Re: Calibration supplier for signal generator with pulse modulation
Hi Gert, I'm sorry, but I don't see that analogy... Cheers, Derek. From: ce-test, qualified testing bv - Gert Gremmen g.grem...@cetest.nl To: dw...@atcb.com; lfresea...@aol.com; deniz.demi...@ntscorp.com; emc-p...@ieee.org Sent: Wed, Aug 11, 2010 1:45 pm Subject: RE: Calibration supplier for signal generator with pulse modulation Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org mailto:emc-p...@ieee.org? ] Namens Dennis Ward Verzonden: woensdag 11 augustus 2010 18:50 Aan: lfresea...@aol.com; deniz.demi...@ntscorp.com; emc-p...@ieee.org Onderwerp: RE: Calibration supplier for signal generator with pulse modulation What’s really needed is a competent individual with adequate equipment” is so important. That’s is exactly the human equivalent of MU; he (she?) knows when a measurement is in error. Gert Gremmen - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
In message c8885bbf.845c4%ken.ja...@emccompliance.com, dated Wed, 11 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: If you live far from the broadcaster, something emitting right at the limit may cause objectionable interference. Even below the limit. I am in a null area for TV from the London Crystal Palace transmitter and even with a high-gain antenna on a 9 m mast, I have EMI problems. People just a few tens of metres away, with less lavish antennas, do not. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
But the uncertainty in that process is huge. So the whole edifice rests on feet of clay. Agreed John, so why worry about a few dB here and there From: John Woodgate j...@jmwa.demon.co.uk To: emc-p...@ieee.org Sent: Wed, Aug 11, 2010 12:31 pm Subject: Re: Calibration supplier for signal generator with pulse modulation In message c88840fe.84571%ken.ja...@emccompliance.com, dated Wed, 11 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: EMI limits are quite arbitrary; Well, not quite. They are set, or re-set, so as to keep complaints of EMI to an acceptable minimum. But the uncertainty in that process is huge. So the whole edifice rests on feet of clay. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
My point exactly. In particular, rfi limits have to be based on some quality of reception that is achieved at some signal-to-noise ratio. If you live in an area with a strong radio signal, a device can emit way more EMI than the limits allow and not cause rfi. If you live far from the broadcaster, something emitting right at the limit may cause objectionable interference. The placement of the limits was deliberate, as Mr. Woodgate states. But the effect of the limits is all over the place. There is simply no way to improve on Mr. Woodgate's closing comment, so I'm not even going to try. Ken Javor Phone: (256) 650-5261 From: John Woodgate j...@jmwa.demon.co.uk Date: Wed, 11 Aug 2010 18:31:43 +0100 To: emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation In message c88840fe.84571%ken.ja...@emccompliance.com, dated Wed, 11 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: EMI limits are quite arbitrary; Well, not quite. They are set, or re-set, so as to keep complaints of EMI to an acceptable minimum. But the uncertainty in that process is huge. So the whole edifice rests on feet of clay. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Calibration supplier for signal generator with pulse modulation
Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens Dennis Ward Verzonden: woensdag 11 augustus 2010 18:50 Aan: lfresea...@aol.com; deniz.demi...@ntscorp.com; emc-p...@ieee.org Onderwerp: RE: Calibration supplier for signal generator with pulse modulation What’s really needed is a competent individual with adequate equipment” is so important. That’s is exactly the human equivalent of MU; he (she?) knows when a measurement is in error. Gert Gremmen - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
In message c88840fe.84571%ken.ja...@emccompliance.com, dated Wed, 11 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: EMI limits are quite arbitrary; Well, not quite. They are set, or re-set, so as to keep complaints of EMI to an acceptable minimum. But the uncertainty in that process is huge. So the whole edifice rests on feet of clay. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Calibration supplier for signal generator with pulse modulation
Ken / Deniz, Speaking of significant digit's: I'm still looking for that EMI receiver that will measure to 1/100 of a dB. So I can report to a 1/10 of a dB in reports like I'm asked to. Michael Sundstrom OHD / TREQ Dallas Electronic Lab Analist, EMC Lead 2170 French Settelment Rd, Suite B Dallas, Texas 75212 (214) 579 6312 From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Wednesday, August 11, 2010 11:59 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Calibration supplier for signal generator with pulse modulation This gets back to Mr. Walton's differentiation between EMI testing and calibration laboratories. Clearly modulation, measured with an o'scope, can be measured to the tolerances available from the o'scope. That's plenty good enough. It strains credulity that there is one brand of scope that would give sloppier results making it easier to pass a test. The essence of what Mr. Walton and I are saying is well-expressed by the rules for using significant digits: You don't get four digit accuracy as the result of computations using two digit accuracy inputs. EMI limits are quite arbitrary; trying to meet them with accuracy exceeding the limit placement process is unnecessary. As stated earlier, the only reason for MU control is on the basic facility chambers/OATS so that there is some repeatability from facility to facility, and so that it isn't easier to pass at one facility than another. Anything beyond that is superfluous and an unnecessary expense. Regarding the example of the cable at 10 GHz. The MIL-STD-461 measurement system integrity check does indeed check that the cable is properly accounted for in terms of attenuation. Mr. Demirci is correct that the signal generator can be expected to be a better match to the cable than is the actual antenna used. However, to the limits of accuracy required for EMI testing, the antenna factor calibration takes care of the mismatch between antenna and cable, since the antenna is calibrated in a 50 Ohm system (albeit likely using pads between antenna and cable for calibration). If further accuracy is desired, most manufacturers provide vswr characteristics for their antennas. Fear isn't the issue. The issue is a misapplication of a process where it isn't required, and the patina of precision and accuracy this dishonestly bestows on an inherently inaccurate and imprecise discipline. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com Date: Wed, 11 Aug 2010 08:35:06 -0700 To: Untitled emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation. Is your tolerance 0.1 % or between 60 % to 90 % is good enough. There is more than a dB peak difference in the signal for 60 % AM and 80 % AM modulations. You won't realize the difference with a field probe in radiated immunity tests with modulated signal. (Simple math; 20*Log(1.6/1.8) = -1.02 dB) It seems not very insignificant to me Another case; If you are using 6 meter cable for radiated emission at 10 GHz, your cable characterization uncertainty is more than 1.5 dB even with a quite high grade cable (Experimental measurements). Check the cable vswr figures in their specs measured in ideal conditions. Even a simple cable is a significant uncertainty contributor. Your measurement antenna is not exactly 50 Ohm at 10 GHz also. Site imperfection is another story. Those figures are not accounted for in the MIL-STD-461 RE102 verification. Everything seems to be very good when you terminate the measurement cable with a signal generator (50 ohm) output. I don't agree with this quote an ultimate proof-of-the-pudding, /quote You can use all your engineering skills for the tests but you have to quantify your risk using type B measurement uncertainty analysis and do the Type A if you can afford to see where you stand. As Mr. Gremmen said MU is not difficult No need to be afraid, OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Wednesday, August 11, 2010 7:55 AM To: Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Precisely. Ken Javor Phone: (256) 650-5261 From: Cortland Richmond k...@earthlink.net Reply-To: k...@earthlink.net Date: Wed, 11 Aug 2010 08:27:34 -0400 To: emc-pstc emc-p...@ieee.org Subject: re: Calibration supplier for signal generator with pulse modulation Not quite what you need to know but I've used signal taps
Re: Calibration supplier for signal generator with pulse modulation
Bingo. Clearly another driver for inserting MU where it doesn't belong is a desire to replace the need for competent personnel with an algorithmic process that works for any personnel. But the same personnel who don’t know how to properly perform the test will also not know how to run the algorithm. Hence Mr. Walton’s observations on how poorly MU is executed in reality. Ken Javor Phone: (256) 650-5261 From: Dennis Ward dw...@atcb.com Reply-To: dw...@atcb.com List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Wed, 11 Aug 2010 09:50:21 -0700 To: lfresea...@aol.com, deniz.demi...@ntscorp.com, emc-p...@ieee.org Subject: RE: Calibration supplier for signal generator with pulse modulation I think I would only add that while measurement uncertainties for EMC is nebulous at best, at the same time we do not want to get into the habit of a slam dunk mentality of ‘oh, just a number, it doesn’t matter.” That is why Derek’s statement of “What’s really needed is a competent individual with adequate equipment” is so important. Where electromagnetic compatibility is concerned, competence of the engineers doing the measurement is probably much more important than uncertainties. I know that one of the biggest benefits to testing in the radio approvals industry is competence of test personnel. Compliance does matter and the best way to keep unneeded uncertainties out of the EMC measurement industry, is to keep competence of test personnel in. Dennis Ward Director of Engineering American TCB Certification Resource for the Wireless Industry www.atcb.com http://www.atcb.com/ http://www.atcb.com/ 703-847-4700 fax 703-847-6888 direct - 703-880-4841 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of lfresea...@aol.com Sent: Wednesday, August 11, 2010 9:00 AM To: deniz.demi...@ntscorp.com; emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation Hi Deniz, this is where real EMI guys differ from Metrology guys. We really don't need to be piddling with little numbers with the exception of frequency. Most of these modulations are compromises, and measuring a compromise accurately is a silly thing to do: in reality. You may want to get on board with the proof of the pudding phrase, it's OK in EMI: otherwise we expend all sorts of effort for no VALUE in return. The compliance world is obsessed with meeting a number, when the REAL reason for doing this testing is to ensure successful operation in use. I strongly disagree with Gerts statement MU is simple, it's not. Of the 140+ labs I've visited as an assessor, only a handful have a valid effort, and less than 1/2 doz believe it was of real value. Precision and EMI do not go together. I for one like it like that. Whats really needed is a competent individual with adequate equipment. If a committee would like MU, then as test labs we should isolate the cost that adds, and identify it on peoples invoices when that test is run. It's an effective way of making the standard unpopular. The reason I'm on a soap box about this is because unless silly requiremnts like this re CHALLENGED, and not just carte-blanche accepted, they become requirements. For calibration, I believe MU is useful, but for EMI, it has no place. Sincerely, Derek. From: Deniz Demirci deniz.demi...@ntscorp.com To: Untitled emc-p...@ieee.org Sent: Wed, Aug 11, 2010 10:35 am Subject: RE: Calibration supplier for signal generator with pulse modulation Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation. Is your tolerance 0.1 % or between 60 % to 90 % is good enough. There is more than a dB peak difference in the signal for 60 % AM and 80 % AM modulations. You won't realize the difference with a field probe in radiated immunity tests with modulated signal. (Simple math; 20*Log(1.6/1.8) = -1.02 dB) It seems not very insignificant to me Another case; If you are using 6 meter cable for radiated emission at 10 GHz, your cable characterization uncertainty is more than 1.5 dB even with a quite high grade cable (Experimental measurements). Check the cable vswr figures in their specs measured in ideal conditions. Even a simple cable is a significant uncertainty contributor. Your measurement antenna is not exactly 50 Ohm at 10 GHz also. Site imperfection is another story. Those figures are not accounted for in the MIL-STD-461 RE102 verification. Everything seems to be very good when you terminate the measurement cable with a signal generator (50 ohm) output. I don't agree with this quote an ultimate proof-of-the-pudding, /quote You can use all your engineering skills for the tests but you have to quantify your risk using type B measurement uncertainty analysis
Re: Calibration supplier for signal generator with pulse modulation
This gets back to Mr. Walton's differentiation between EMI testing and calibration laboratories. Clearly modulation, measured with an o'scope, can be measured to the tolerances available from the o'scope. That's plenty good enough. It strains credulity that there is one brand of scope that would give sloppier results making it easier to pass a test. The essence of what Mr. Walton and I are saying is well-expressed by the rules for using significant digits: You don't get four digit accuracy as the result of computations using two digit accuracy inputs. EMI limits are quite arbitrary; trying to meet them with accuracy exceeding the limit placement process is unnecessary. As stated earlier, the only reason for MU control is on the basic facility chambers/OATS so that there is some repeatability from facility to facility, and so that it isn't easier to pass at one facility than another. Anything beyond that is superfluous and an unnecessary expense. Regarding the example of the cable at 10 GHz. The MIL-STD-461 measurement system integrity check does indeed check that the cable is properly accounted for in terms of attenuation. Mr. Demirci is correct that the signal generator can be expected to be a better match to the cable than is the actual antenna used. However, to the limits of accuracy required for EMI testing, the antenna factor calibration takes care of the mismatch between antenna and cable, since the antenna is calibrated in a 50 Ohm system (albeit likely using pads between antenna and cable for calibration). If further accuracy is desired, most manufacturers provide vswr characteristics for their antennas. Fear isn't the issue. The issue is a misapplication of a process where it isn't required, and the patina of precision and accuracy this dishonestly bestows on an inherently inaccurate and imprecise discipline. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com Date: Wed, 11 Aug 2010 08:35:06 -0700 To: Untitled emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation. Is your tolerance 0.1 % or between 60 % to 90 % is good enough. There is more than a dB peak difference in the signal for 60 % AM and 80 % AM modulations. You won't realize the difference with a field probe in radiated immunity tests with modulated signal. (Simple math; 20*Log(1.6/1.8) = -1.02 dB) It seems not very insignificant to me Another case; If you are using 6 meter cable for radiated emission at 10 GHz, your cable characterization uncertainty is more than 1.5 dB even with a quite high grade cable (Experimental measurements). Check the cable vswr figures in their specs measured in ideal conditions. Even a simple cable is a significant uncertainty contributor. Your measurement antenna is not exactly 50 Ohm at 10 GHz also. Site imperfection is another story. Those figures are not accounted for in the MIL-STD-461 RE102 verification. Everything seems to be very good when you terminate the measurement cable with a signal generator (50 ohm) output. I don't agree with this quote an ultimate proof-of-the-pudding, /quote You can use all your engineering skills for the tests but you have to quantify your risk using type B measurement uncertainty analysis and do the Type A if you can afford to see where you stand. As Mr. Gremmen said MU is not difficult No need to be afraid, OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Wednesday, August 11, 2010 7:55 AM To: Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Precisely. Ken Javor Phone: (256) 650-5261 From: Cortland Richmond k...@earthlink.net Reply-To: k...@earthlink.net Date: Wed, 11 Aug 2010 08:27:34 -0400 To: emc-pstc emc-p...@ieee.org Subject: re: Calibration supplier for signal generator with pulse modulation Not quite what you need to know but I've used signal taps or directional couplers with a 'scope to watch the RF waveform and set modulation depth, and a calibrated counter, or even a receiver or analyzer will for frequency. One always has recourse to calibrated devices to monitor another, uncalibrated one. It's a good idea anyway! If a detector must be used whose linearity is unknown, one can use calibrated attenuators to find out. Cortland Richmond KA5S [Original Message] From: Wendy Nya wendy...@yahoo.com To: emc-p...@ieee.org Date: 8/10/2010 4:23:29 AM Subject
RE: Calibration supplier for signal generator with pulse modulation
I think I would only add that while measurement uncertainties for EMC is nebulous at best, at the same time we do not want to get into the habit of a slam dunk mentality of ‘oh, just a number, it doesn’t matter.” That is why Derek’s statement of “What’s really needed is a competent individual with adequate equipment” is so important. Where electromagnetic compatibility is concerned, competence of the engineers doing the measurement is probably much more important than uncertainties. I know that one of the biggest benefits to testing in the radio approvals industry is competence of test personnel. Compliance does matter and the best way to keep unneeded uncertainties out of the EMC measurement industry, is to keep competence of test personnel in. Dennis Ward Director of Engineering American TCB Certification Resource for the Wireless Industry www.atcb.com http://www.atcb.com/ 703-847-4700 fax 703-847-6888 direct - 703-880-4841 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of lfresea...@aol.com Sent: Wednesday, August 11, 2010 9:00 AM To: deniz.demi...@ntscorp.com; emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation Hi Deniz, this is where real EMI guys differ from Metrology guys. We really don't need to be piddling with little numbers with the exception of frequency. Most of these modulations are compromises, and measuring a compromise accurately is a silly thing to do: in reality. You may want to get on board with the proof of the pudding phrase, it's OK in EMI: otherwise we expend all sorts of effort for no VALUE in return. The compliance world is obsessed with meeting a number, when the REAL reason for doing this testing is to ensure successful operation in use. I strongly disagree with Gerts statement MU is simple, it's not. Of the 140+ labs I've visited as an assessor, only a handful have a valid effort, and less than 1/2 doz believe it was of real value. Precision and EMI do not go together. I for one like it like that. Whats really needed is a competent individual with adequate equipment. If a committee would like MU, then as test labs we should isolate the cost that adds, and identify it on peoples invoices when that test is run. It's an effective way of making the standard unpopular. The reason I'm on a soap box about this is because unless silly requiremnts like this re CHALLENGED, and not just carte-blanche accepted, they become requirements. For calibration, I believe MU is useful, but for EMI, it has no place. Sincerely, Derek. From: Deniz Demirci deniz.demi...@ntscorp.com To: Untitled emc-p...@ieee.org Sent: Wed, Aug 11, 2010 10:35 am Subject: RE: Calibration supplier for signal generator with pulse modulation Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation. Is your tolerance 0.1 % or between 60 % to 90 % is good enough. There is more than a dB peak difference in the signal for 60 % AM and 80 % AM modulations. You won't realize the difference with a field probe in radiated immunity tests with modulated signal. (Simple math; 20*Log(1.6/1.8) = -1.02 dB) It seems not very insignificant to me Another case; If you are using 6 meter cable for radiated emission at 10 GHz, your cable characterization uncertainty is more than 1.5 dB even with a quite high grade cable (Experimental measurements). Check the cable vswr figures in their specs measured in ideal conditions. Even a simple cable is a significant uncertainty contributor. Your measurement antenna is not exactly 50 Ohm at 10 GHz also. Site imperfection is another story. Those figures are not accounted for in the MIL-STD-461 RE102 verification. Everything seems to be very good when you terminate the measurement cable with a signal generator (50 ohm) output. I don't agree with this quote an ultimate proof-of-the-pudding, /quote You can use all your engineering skills for the tests but you have to quantify your risk using type B measurement uncertainty analysis and do the Type A if you can afford to see where you stand. As Mr. Gremmen said MU is not difficult No need to be afraid, OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations From: emc-p...@ieee.org [mailto:emc-p...@ieee.org mailto:emc-p...@ieee.org? ] On Behalf Of Ken Javor Sent: Wednesday, August 11, 2010 7:55 AM To: Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Precisely
Re: Calibration supplier for signal generator with pulse modulation
Hi Deniz, this is where real EMI guys differ from Metrology guys. We really don't need to be piddling with little numbers with the exception of frequency. Most of these modulations are compromises, and measuring a compromise accurately is a silly thing to do: in reality. You may want to get on board with the proof of the pudding phrase, it's OK in EMI: otherwise we expend all sorts of effort for no VALUE in return. The compliance world is obsessed with meeting a number, when the REAL reason for doing this testing is to ensure successful operation in use. I strongly disagree with Gerts statement MU is simple, it's not. Of the 140+ labs I've visited as an assessor, only a handful have a valid effort, and less than 1/2 doz believe it was of real value. Precision and EMI do not go together. I for one like it like that. Whats really needed is a competent individual with adequate equipment. If a committee would like MU, then as test labs we should isolate the cost that adds, and identify it on peoples invoices when that test is run. It's an effective way of making the standard unpopular. The reason I'm on a soap box about this is because unless silly requiremnts like this re CHALLENGED, and not just carte-blanche accepted, they become requirements. For calibration, I believe MU is useful, but for EMI, it has no place. Sincerely, Derek. From: Deniz Demirci deniz.demi...@ntscorp.com To: Untitled emc-p...@ieee.org Sent: Wed, Aug 11, 2010 10:35 am Subject: RE: Calibration supplier for signal generator with pulse modulation Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation. Is your tolerance 0.1 % or between 60 % to 90 % is good enough. There is more than a dB peak difference in the signal for 60 % AM and 80 % AM modulations. You won't realize the difference with a field probe in radiated immunity tests with modulated signal. (Simple math; 20*Log(1.6/1.8) = -1.02 dB) It seems not very insignificant to me Another case; If you are using 6 meter cable for radiated emission at 10 GHz, your cable characterization uncertainty is more than 1.5 dB even with a quite high grade cable (Experimental measurements). Check the cable vswr figures in their specs measured in ideal conditions. Even a simple cable is a significant uncertainty contributor. Your measurement antenna is not exactly 50 Ohm at 10 GHz also. Site imperfection is another story. Those figures are not accounted for in the MIL-STD-461 RE102 verification. Everything seems to be very good when you terminate the measurement cable with a signal generator (50 ohm) output. I don't agree with this quote an ultimate proof-of-the-pudding, /quote You can use all your engineering skills for the tests but you have to quantify your risk using type B measurement uncertainty analysis and do the Type A if you can afford to see where you stand. As Mr. Gremmen said MU is not difficult No need to be afraid, OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations From: emc-p...@ieee.org [mailto:emc-p...@ieee.org mailto:emc-p...@ieee.org? ] On Behalf Of Ken Javor Sent: Wednesday, August 11, 2010 7:55 AM To: Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Precisely. Ken Javor Phone: (256) 650-5261 From: Cortland Richmond k...@earthlink.net Reply-To: k...@earthlink.net Date: Wed, 11 Aug 2010 08:27:34 -0400 To: emc-pstc emc-p...@ieee.org Subject: re: Calibration supplier for signal generator with pulse modulation Not quite what you need to know but I've used signal taps or directional couplers with a 'scope to watch the RF waveform and set modulation depth, and a calibrated counter, or even a receiver or analyzer will for frequency. One always has recourse to calibrated devices to monitor another, uncalibrated one. It's a good idea anyway! If a detector must be used whose linearity is unknown, one can use calibrated attenuators to find out. Cortland Richmond KA5S [Original Message] From: Wendy Nya wendy...@yahoo.com To: emc-p...@ieee.org Date: 8/10/2010 4:23:29 AM Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide
RE: Calibration supplier for signal generator with pulse modulation
Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation. Is your tolerance 0.1 % or between 60 % to 90 % is good enough. There is more than a dB peak difference in the signal for 60 % AM and 80 % AM modulations. You won't realize the difference with a field probe in radiated immunity tests with modulated signal. (Simple math; 20*Log(1.6/1.8) = -1.02 dB) It seems not very insignificant to me Another case; If you are using 6 meter cable for radiated emission at 10 GHz, your cable characterization uncertainty is more than 1.5 dB even with a quite high grade cable (Experimental measurements). Check the cable vswr figures in their specs measured in ideal conditions. Even a simple cable is a significant uncertainty contributor. Your measurement antenna is not exactly 50 Ohm at 10 GHz also. Site imperfection is another story. Those figures are not accounted for in the MIL-STD-461 RE102 verification. Everything seems to be very good when you terminate the measurement cable with a signal generator (50 ohm) output. I don't agree with this quote an ultimate proof-of-the-pudding, /quote You can use all your engineering skills for the tests but you have to quantify your risk using type B measurement uncertainty analysis and do the Type A if you can afford to see where you stand. As Mr. Gremmen said MU is not difficult No need to be afraid, OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Wednesday, August 11, 2010 7:55 AM To: Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Precisely. Ken Javor Phone: (256) 650-5261 From: Cortland Richmond k...@earthlink.net Reply-To: k...@earthlink.net Date: Wed, 11 Aug 2010 08:27:34 -0400 To: emc-pstc emc-p...@ieee.org Subject: re: Calibration supplier for signal generator with pulse modulation Not quite what you need to know but I've used signal taps or directional couplers with a 'scope to watch the RF waveform and set modulation depth, and a calibrated counter, or even a receiver or analyzer will for frequency. One always has recourse to calibrated devices to monitor another, uncalibrated one. It's a good idea anyway! If a detector must be used whose linearity is unknown, one can use calibrated attenuators to find out. Cortland Richmond KA5S [Original Message] From: Wendy Nya wendy...@yahoo.com To: emc-p...@ieee.org Date: 8/10/2010 4:23:29 AM Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived
Re: Calibration supplier for signal generator with pulse modulation
In message c88815fd.844e8%ken.ja...@emccompliance.com, dated Wed, 11 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: Precisely. ... or should that be 'accurately'. We must use these meteorological terms correctly! (;-) -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
Precisely. Ken Javor Phone: (256) 650-5261 From: Cortland Richmond k...@earthlink.net Reply-To: k...@earthlink.net Date: Wed, 11 Aug 2010 08:27:34 -0400 To: emc-pstc emc-p...@ieee.org Subject: re: Calibration supplier for signal generator with pulse modulation Not quite what you need to know but I've used signal taps or directional couplers with a 'scope to watch the RF waveform and set modulation depth, and a calibrated counter, or even a receiver or analyzer will for frequency. One always has recourse to calibrated devices to monitor another, uncalibrated one. It's a good idea anyway! If a detector must be used whose linearity is unknown, one can use calibrated attenuators to find out. Cortland Richmond KA5S [Original Message] From: Wendy Nya wendy...@yahoo.com To: emc-p...@ieee.org Date: 8/10/2010 4:23:29 AM Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
Absolutely incorrect. The signal simply needs to be measured with a calibrated instrument. Ken Javor Phone: (256) 650-5261 From: Gärdin Petter petter.gar...@saabgroup.com List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Wed, 11 Aug 2010 13:18:05 + To: EMC-PSTC@LISTSERV.IEEE.ORG EMC-PSTC@LISTSERV.IEEE.ORG Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation And now almost getting back to the original question and a quote from Ken, the measurement system integrity check in MIL-STD-461 in which a calibrated input signal corresponding to a level 6 dB below the limit is applied at the transducer end of the measurement system, and the EMI receiver must measure that signal accurately within +/- 3 dB. And the calibrated input signal should come from a calibrated signal generator, meaning that the signal generator need to be calibrated. Petter Gärdin From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: den 10 augusti 2010 23:05 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Calibration supplier for signal generator with pulse modulation This excerpt from Mr. Demirci‘s message below is the kernel of the issue: “I believe a proper measurement uncertainty assessment will decrease the different measurement / test results between accredited laboratories for the same product. Then, manufacturer / designer will not shop for a laboratory which he / she will get an easy pass test report.” In the days of OATS and ANSI C63,4, an NSA correlation of +/- 4 dB sufficed. In the days of SACS and FACS, some sort of similar measurement is clearly required. But this facility certification in no way extends to mundane measurements that are made with an ordinary instrument such as an o’scope, or handheld meter, or for that matter, an EMI receiver. Those measurements are controlled by using a calibrated device, and even better, much better: the measurement system integrity check in MIL-STD-461 in which a calibrated input signal corresponding to a level 6 dB below the limit is applied at the transducer end of the measurement system, and the EMI receiver must measure that signal accurately within +/- 3 dB. That is the ultimate “proof-of-the-pudding,” with the exception that it doesn’t account for chamber effects for radiated emissions. There are a couple reasons that military and automotive and commercial aerospace EMI testing do not require measurement uncertainty. One is the ancient dictum, “If you can’t stand the answer, don’t ask the question.” That is, we know a priori, before performing the exercise, that one meter separation radiated measurements from an extended test set-up in an imperfectly anechoic chamber are not going to result in pretty uncertainty numbers. The reason that this is ultimately acceptable goes back to the above excerpt from the message below from Mr. Demirci. In the commercial world, you must EMI qualify before going to market. In that case, you need all EMI test facilities to be equal. In the world of military, automotive and aerospace, the EMI qualification is usually done as a collaborative effort between vendor and customer, and is performed after a decision has been made that the customer will do business with the vendor. That is all background. The unalterable fact, regardless of how MU has been misapplied and perverted, is that it applies to the measurement facility itself; something that inherently will have an uncertainty on the order of several dB. It does not apply to things that can be measured to tenths of a dB, or are not even spec’d in dB, such as the modulation waveform of a signal generator, or its frequency accuracy. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Tue, 10 Aug 2010 10:39:37 -0700 To: emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation I guess the equipments in Apollo project hasn’t only pass the tests with no margin :-) They may have required quite a big margin so MU is not an issue at all… Commercial world can be quite a bit different in that matter. They can’t afford 10 dB margin. Has anyone seen a consumer electronic product will pass 10 dB Class B emission limits ? I believe a proper measurement uncertainty assessment will decrease the different measurement / test results between accredited laboratories for the same product. Then, manufacturer / designer will not shop for a laboratory which he / she will get an easy pass test report. OOO (Own opinions only) Best regards
RE: Calibration supplier for signal generator with pulse modulation
And now almost getting back to the original question and a quote from Ken, the measurement system integrity check in MIL-STD-461 in which a calibrated input signal corresponding to a level 6 dB below the limit is applied at the transducer end of the measurement system, and the EMI receiver must measure that signal accurately within +/- 3 dB. And the calibrated input signal should come from a calibrated signal generator, meaning that the signal generator need to be calibrated. Petter Gärdin From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: den 10 augusti 2010 23:05 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Calibration supplier for signal generator with pulse modulation This excerpt from Mr. Demirci‘s message below is the kernel of the issue: “I believe a proper measurement uncertainty assessment will decrease the different measurement / test results between accredited laboratories for the same product. Then, manufacturer / designer will not shop for a laboratory which he / she will get an easy pass test report.” In the days of OATS and ANSI C63,4, an NSA correlation of +/- 4 dB sufficed. In the days of SACS and FACS, some sort of similar measurement is clearly required. But this facility certification in no way extends to mundane measurements that are made with an ordinary instrument such as an o’scope, or handheld meter, or for that matter, an EMI receiver. Those measurements are controlled by using a calibrated device, and even better, much better: the measurement system integrity check in MIL-STD-461 in which a calibrated input signal corresponding to a level 6 dB below the limit is applied at the transducer end of the measurement system, and the EMI receiver must measure that signal accurately within +/- 3 dB. That is the ultimate “proof-of-the-pudding,” with the exception that it doesn’t account for chamber effects for radiated emissions. There are a couple reasons that military and automotive and commercial aerospace EMI testing do not require measurement uncertainty. One is the ancient dictum, “If you can’t stand the answer, don’t ask the question.” That is, we know a priori, before performing the exercise, that one meter separation radiated measurements from an extended test set-up in an imperfectly anechoic chamber are not going to result in pretty uncertainty numbers. The reason that this is ultimately acceptable goes back to the above excerpt from the message below from Mr. Demirci. In the commercial world, you must EMI qualify before going to market. In that case, you need all EMI test facilities to be equal. In the world of military, automotive and aerospace, the EMI qualification is usually done as a collaborative effort between vendor and customer, and is performed after a decision has been made that the customer will do business with the vendor. That is all background. The unalterable fact, regardless of how MU has been misapplied and perverted, is that it applies to the measurement facility itself; something that inherently will have an uncertainty on the order of several dB. It does not apply to things that can be measured to tenths of a dB, or are not even spec’d in dB, such as the modulation waveform of a signal generator, or its frequency accuracy. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Tue, 10 Aug 2010 10:39:37 -0700 To: emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation I guess the equipments in Apollo project hasn’t only pass the tests with no margin :-) They may have required quite a big margin so MU is not an issue at all… Commercial world can be quite a bit different in that matter. They can’t afford 10 dB margin. Has anyone seen a consumer electronic product will pass 10 dB Class B emission limits ? I believe a proper measurement uncertainty assessment will decrease the different measurement / test results between accredited laboratories for the same product. Then, manufacturer / designer will not shop for a laboratory which he / she will get an easy pass test report. OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations http://www.ntscorp.com/about/locations http://www.ntscorp.com/about/locations From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of lfresea...@aol.com Sent: Tuesday, August 10, 2010 11:07 AM To: j...@jmwa.demon.co.uk; emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation HI John, just stressing Ken's use of the word unwarranted. I'm
re: Calibration supplier for signal generator with pulse modulation
Not quite what you need to know but I've used signal taps or directional couplers with a 'scope to watch the RF waveform and set modulation depth, and a calibrated counter, or even a receiver or analyzer will for frequency. One always has recourse to calibrated devices to monitor another, uncalibrated one. It's a good idea anyway! If a detector must be used whose linearity is unknown, one can use calibrated attenuators to find out. Cortland Richmond KA5S [Original Message] From: Wendy Nya wendy...@yahoo.com To: emc-p...@ieee.org Date: 8/10/2010 4:23:29 AM Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Calibration supplier for signal generator with pulse modulation
Not quite what you need to know but I've used signal taps or directional couplers with a 'scope to watch the RF waveform and set modulation depth, and a calibrated counter, or even a receiver or analyzer will for frequency. One always has recourse to calibrated devices to monitor another, uncalibrated one. It's a good idea anyway! If a detector must be used whose linearity is unknown, one can use calibrated attenuators to find out. Cortland Richmond KA5S [Original Message] From: Wendy Nya wendy...@yahoo.com To: emc-p...@ieee.org Date: 8/10/2010 4:23:29 AM Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
There is a fundamental difference between assigning an uncertainty factor that is in fact a hard number, like NSA, vs. something that has to be wagged, like the effect of cable placement on radiation efficiency in the direction of an antenna. In fact, this is an excellent example of when a large, but uncontrolled uncertainty points us in the direction of another control altogether. The radiation efficiency of a cable, relative to its max efficiency, will vary from something close to zero, up to one. Obviously some assumptions are made that place the actual efficiency somewhere in the vicinity of unity, with some uncertainty as to how close unity is approached, based on assumptions about the quality of test personnel, and the time they take to do the maximizing. This is an area where human engineering, or perhaps human factors has to be factored into the test equation. If a test sample is very quiet, some quick cable manipulations can be performed, and if no significant changes are observed, there is no point in further effort. Likewise, if a test sample is very noisy, there isn't any point in maximizing emissions. It is only when something is just passing that it is important to take time to move the cables to maximize emissions. It is precisely here, that to the test customer, it appears the test house is spending his money (time to manipulate cables and scan and re-scan) to fail him. A much better approach was promoted about thirty years ago by a European EMC engineer named Balint Szentkuti: control cable common mode emissions over the 30 - 1000 MHz band, perhaps using the absorbing clamp to give better accuracy at these frequencies than a current probe. The limit, in dBuA, would be derived to yield the radiated emission limit at three or ten meters based on a perfectly maximized cable radiation pattern. Once that test had been performed and passed, it would be on to the radiated emission test, where cable manipulation would no longer be part of the test regime, and any emissions in excess of the limit could be dealt with by looking at the test sample enclosure and or the circuitry within. Ken Javor Phone: (256) 650-5261 From: John Woodgate j...@jmwa.demon.co.uk Date: Tue, 10 Aug 2010 22:33:13 +0100 To: emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation In message c8872923.84265%ken.ja...@emccompliance.com, dated Tue, 10 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: That is all background. The unalterable fact, regardless of how MU has been misapplied and perverted, is that it applies to the measurement facility itself; something that inherently will have an uncertainty on the order of several dB. It does not apply to things that can be measured to tenths of a dB, or are not even spec?d in dB, such as the modulation waveform of a signal generator, or its frequency accuracy. CISPR 16-4-1 appears to disagree, citing things like the height of the antenna and even 'routing of cables' as having uncertainty assessment applied to them (clause 4.2.4). -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
In message c8872923.84265%ken.ja...@emccompliance.com, dated Tue, 10 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: That is all background. The unalterable fact, regardless of how MU has been misapplied and perverted, is that it applies to the measurement facility itself; something that inherently will have an uncertainty on the order of several dB. It does not apply to things that can be measured to tenths of a dB, or are not even spec?d in dB, such as the modulation waveform of a signal generator, or its frequency accuracy. CISPR 16-4-1 appears to disagree, citing things like the height of the antenna and even 'routing of cables' as having uncertainty assessment applied to them (clause 4.2.4). -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
This excerpt from Mr. Demirci‘s message below is the kernel of the issue: “I believe a proper measurement uncertainty assessment will decrease the different measurement / test results between accredited laboratories for the same product. Then, manufacturer / designer will not shop for a laboratory which he / she will get an easy pass test report.” In the days of OATS and ANSI C63,4, an NSA correlation of +/- 4 dB sufficed. In the days of SACS and FACS, some sort of similar measurement is clearly required. But this facility certification in no way extends to mundane measurements that are made with an ordinary instrument such as an o’scope, or handheld meter, or for that matter, an EMI receiver. Those measurements are controlled by using a calibrated device, and even better, much better: the measurement system integrity check in MIL-STD-461 in which a calibrated input signal corresponding to a level 6 dB below the limit is applied at the transducer end of the measurement system, and the EMI receiver must measure that signal accurately within +/- 3 dB. That is the ultimate “proof-of-the-pudding,” with the exception that it doesn’t account for chamber effects for radiated emissions. There are a couple reasons that military and automotive and commercial aerospace EMI testing do not require measurement uncertainty. One is the ancient dictum, “If you can’t stand the answer, don’t ask the question.” That is, we know a priori, before performing the exercise, that one meter separation radiated measurements from an extended test set-up in an imperfectly anechoic chamber are not going to result in pretty uncertainty numbers. The reason that this is ultimately acceptable goes back to the above excerpt from the message below from Mr. Demirci. In the commercial world, you must EMI qualify before going to market. In that case, you need all EMI test facilities to be equal. In the world of military, automotive and aerospace, the EMI qualification is usually done as a collaborative effort between vendor and customer, and is performed after a decision has been made that the customer will do business with the vendor. That is all background. The unalterable fact, regardless of how MU has been misapplied and perverted, is that it applies to the measurement facility itself; something that inherently will have an uncertainty on the order of several dB. It does not apply to things that can be measured to tenths of a dB, or are not even spec’d in dB, such as the modulation waveform of a signal generator, or its frequency accuracy. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Tue, 10 Aug 2010 10:39:37 -0700 To: emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation I guess the equipments in Apollo project hasn’t only pass the tests with no margin :-) They may have required quite a big margin so MU is not an issue at all… Commercial world can be quite a bit different in that matter. They can’t afford 10 dB margin. Has anyone seen a consumer electronic product will pass 10 dB Class B emission limits ? I believe a proper measurement uncertainty assessment will decrease the different measurement / test results between accredited laboratories for the same product. Then, manufacturer / designer will not shop for a laboratory which he / she will get an easy pass test report. OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations http://www.ntscorp.com/about/locations http://www.ntscorp.com/about/locations From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of lfresea...@aol.com Sent: Tuesday, August 10, 2010 11:07 AM To: j...@jmwa.demon.co.uk; emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation HI John, just stressing Ken's use of the word unwarranted. I'm personally vehemently opposed to MU in EMC measurements: the reason why is that end to end even 10 dB is a trivial error... Just because the Stds committee says so does not make it warranted. All MU contributes is an academic exercise and lines pockets of individuals/organizations pushing it. We as an EMC community need to push back and say enough already. Our efforts are needed to address more important problems. Just for the record, Automotive EMC does not require MU, US Military to not require MU. If MU wasn't needed to put a man on the moon it sure as heck isnt needed in washing machines, computers etc. I'm guessing this is more than 10 cents worth! Derek Walton L F Research. From: John Woodgate j...@jmwa.demon.co.uk
RE: Calibration supplier for signal generator with pulse modulation
. IT DOES NOT GIVE YOU ACCURATE NUMBERS. That is the basis of MU, instead of not knowing how inaccurate, nobody introduces MU for the sake of ACCURATE numbers, just to define how INACCURATE they are. CISPR16 get a range of obtainable inaccuracy, in practice +/- 6 dB (50-200%) I admit, using a defined EUT only. But +/- 6 dB is pretty compatible to your example of the jello. And nobody said we’d introduce a micrometer accuracy instrument in EMC by introducing MU. For the low hanging fruit… regarding measurement methods…. please learn us something Gert Van: lfresea...@aol.com [mailto:lfresea...@aol.com] Verzonden: dinsdag 10 augustus 2010 21:16 Aan: ce-test, qualified testing bv - Gert Gremmen; j...@jmwa.demon.co.uk; emc-p...@ieee.org Onderwerp: Re: Calibration supplier for signal generator with pulse modulation Hi Gert, I think you would be better saying MU muddies the water on what you might be measuring. IT DOES NOT GIVE YOU ACCURATE NUMBERS. Anyone that thinks EMC is metrology, especially when they only focus on a small part of the big picture, is unnecessary adding cost and complexity to a measurement process. Can anyone put their hand on their heart and say +/-10 db on an OATS really makes a difference in use? What about complying with a limit when there's never going to be anything in the are to be interfered with? Before MU needs to be used in EMC, there are many other low hanging fruit to pick first with much better payback in cost reductions or reproducibility. I like the measure jello with a micrometer analogy Cheers, Derek. From: ce-test, qualified testing bv - Gert Gremmen g.grem...@cetest.nl To: lfresea...@aol.com; j...@jmwa.demon.co.uk; emc-p...@ieee.org Sent: Tue, Aug 10, 2010 12:34 pm Subject: RE: Calibration supplier for signal generator with pulse modulation MU is of course the only way of knowing what you do/measure and ultimately test. But if it need to be taken into account…. is another story. But if you do not know where your errors are, I guess you can better stop measuring. In most metrological approaches only the hardware measurement chain is evaluated (antenna-cabling-measuring device), and default value is used for the transfer between EUT through OATS/SAR/FAR. And –as all of you know- the EMC community itself came up with a MU criterion (sort of) for that: the Normalized Site Attenuation with it’s +/4 dB margins (using a well defined simple source) This can be combined with the standard uncertainty of your measurement chain to get a total MU value. Most calcs result in 4-6 dB of MU More can be found in the appropriate part of CISPR 16 (part -4-2) of which I don’t have the exact reference at hand… someone ?? Gert Gremmen ce-test, qualified testing bv Van: emc-p...@ieee.org mailto:emc-p...@ieee.org [mailto:emc-p...@ieee.org mailto:emc-p...@ieee.org? ] Namens lfresea...@aol.com mailto:lfresea...@aol.com Verzonden: dinsdag 10 augustus 2010 19:07 Aan: j...@jmwa.demon.co.uk mailto:j...@jmwa.demon.co.uk ; emc-p...@ieee.org mailto:emc-p...@ieee.org Onderwerp: Re: Calibration supplier for signal generator with pulse modulation HI John, just stressing Ken's use of the word unwarranted. I'm personally vehemently opposed to MU in EMC measurements: the reason why is that end to end even 10 dB is a trivial error... Just because the Stds committee says so does not make it warranted. All MU contributes is an academic exercise and lines pockets of individuals/organizations pushing it. We as an EMC community need to push back and say enough already. Our efforts are needed to address more important problems. Just for the record, Automotive EMC does not require MU, US Military to not require MU. If MU wasn't needed to put a man on the moon it sure as heck isnt needed in washing machines, computers etc. I'm guessing this is more than 10 cents worth! Derek Walton L F Research. From: John Woodgate j...@jmwa.demon.co.uk mailto:j...@jmwa.demon.co.uk To: emc-p...@ieee.org mailto:emc-p...@ieee.org Sent: Tue, Aug 10, 2010 11:46 am Subject: Re: Calibration supplier for signal generator with pulse modulation In message c886e31f.841a0%ken.ja...@emccompliance.com mailto:ken.ja...@emccompliance.com , dated Tue, 10 Aug 2010, Ken Javor ken.ja...@emccompliance.com mailto:ken.ja...@emccompliance.com writes: Uncertainty for modulation parameters of depth or pulse on-off ratio and time duration? Uncertainty applies to things like field intensity, where the construction of the room or OATS and near field effects combine to provide significant uncertainty. But something easily measured with an o'scope of modest (audio) performance? That is a totally unwarranted extension of the concept. Unfortunately, it isn't. The metrologists have inflicted formal uncertainty assessment on us and it's like death and taxes - always with us. Everything has to have its uncertainty assessed
Re: Calibration supplier for signal generator with pulse modulation
Hi Gert, I think you would be better saying MU muddies the water on what you might be measuring. IT DOES NOT GIVE YOU ACCURATE NUMBERS. Anyone that thinks EMC is metrology, especially when they only focus on a small part of the big picture, is unnecessary adding cost and complexity to a measurement process. Can anyone put their hand on their heart and say +/-10 db on an OATS really makes a difference in use? What about complying with a limit when there's never going to be anything in the are to be interfered with? Before MU needs to be used in EMC, there are many other low hanging fruit to pick first with much better payback in cost reductions or reproducibility. I like the measure jello with a micrometer analogy Cheers, Derek. From: ce-test, qualified testing bv - Gert Gremmen g.grem...@cetest.nl To: lfresea...@aol.com; j...@jmwa.demon.co.uk; emc-p...@ieee.org Sent: Tue, Aug 10, 2010 12:34 pm Subject: RE: Calibration supplier for signal generator with pulse modulation MU is of course the only way of knowing what you do/measure and ultimately test. But if it need to be taken into account…. is another story. But if you do not know where your errors are, I guess you can better stop measuring. In most metrological approaches only the hardware measurement chain is evaluated (antenna-cabling-measuring device), and default value is used for the transfer between EUT through OATS/SAR/FAR. And –as all of you know- the EMC community itself came up with a MU criterion (sort of) for that: the Normalized Site Attenuation with it’s +/4 dB margins (using a well defined simple source) This can be combined with the standard uncertainty of your measurement chain to get a total MU value. Most calcs result in 4-6 dB of MU More can be found in the appropriate part of CISPR 16 (part -4-2) of which I don’t have the exact reference at hand… someone ?? Gert Gremmen ce-test, qualified testing bv Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org mailto:emc-p...@ieee.org? ] Namens lfresea...@aol.com Verzonden: dinsdag 10 augustus 2010 19:07 Aan: j...@jmwa.demon.co.uk; emc-p...@ieee.org Onderwerp: Re: Calibration supplier for signal generator with pulse modulation HI John, just stressing Ken's use of the word unwarranted. I'm personally vehemently opposed to MU in EMC measurements: the reason why is that end to end even 10 dB is a trivial error... Just because the Stds committee says so does not make it warranted. All MU contributes is an academic exercise and lines pockets of individuals/organizations pushing it. We as an EMC community need to push back and say enough already. Our efforts are needed to address more important problems. Just for the record, Automotive EMC does not require MU, US Military to not require MU. If MU wasn't needed to put a man on the moon it sure as heck isnt needed in washing machines, computers etc. I'm guessing this is more than 10 cents worth! Derek Walton L F Research. From: John Woodgate j...@jmwa.demon.co.uk To: emc-p...@ieee.org Sent: Tue, Aug 10, 2010 11:46 am Subject: Re: Calibration supplier for signal generator with pulse modulation In message c886e31f.841a0%ken.ja...@emccompliance.com, dated Tue, 10 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: Uncertainty for modulation parameters of depth or pulse on-off ratio and time duration? Uncertainty applies to things like field intensity, where the construction of the room or OATS and near field effects combine to provide significant uncertainty. But something easily measured with an o'scope of modest (audio) performance? That is a totally unwarranted extension of the concept. Unfortunately, it isn't. The metrologists have inflicted formal uncertainty assessment on us and it's like death and taxes - always with us. Everything has to have its uncertainty assessed. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc
Re: Calibration supplier for signal generator with pulse modulation
In message 8cd06c5a43f24be-12a8-...@webmail-m087.sysops.aol.com, dated Tue, 10 Aug 2010, lfresea...@aol.com writes: just stressing Ken's use of the word unwarranted. I'm personally vehemently opposed to MU in EMC measurements: the reason why is that end to end even 10 dB is a trivial error... I entirely agree. I have defined the term 'measuring jelly (Jello) with a micrometer' to describe the application of MU to EMC. Just because the Stds committee says so does not make it warranted. All MU contributes is an academic exercise and lines pockets of individuals/organizations pushing it. Agreed. We as an EMC community need to push back and say enough already. Our efforts are needed to address more important problems. But ISO, IEC and CISPR have accepted it and I doubt that it can be eradicated now. Just for the record, Automotive EMC does not require MU, US Military to not require MU. If MU wasn't needed to put a man on the moon it sure as heck isnt needed in washing machines, computers etc. You make a strong point. Now make it to ANSI and the IEEE and see whether the might of the USA standards bodies can convince ISO and IEC to re-think (or even to think, never mind the 're'!). -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: Calibration supplier for signal generator with pulse modulation
I guess the equipments in Apollo project hasn’t only pass the tests with no margin J They may have required quite a big margin so MU is not an issue at all… Commercial world can be quite a bit different in that matter. They can’t afford 10 dB margin. Has anyone seen a consumer electronic product will pass 10 dB Class B emission limits ? I believe a proper measurement uncertainty assessment will decrease the different measurement / test results between accredited laboratories for the same product. Then, manufacturer / designer will not shop for a laboratory which he / she will get an easy pass test report. OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations http://www.ntscorp.com/about/locations From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of lfresea...@aol.com Sent: Tuesday, August 10, 2010 11:07 AM To: j...@jmwa.demon.co.uk; emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation HI John, just stressing Ken's use of the word unwarranted. I'm personally vehemently opposed to MU in EMC measurements: the reason why is that end to end even 10 dB is a trivial error... Just because the Stds committee says so does not make it warranted. All MU contributes is an academic exercise and lines pockets of individuals/organizations pushing it. We as an EMC community need to push back and say enough already. Our efforts are needed to address more important problems. Just for the record, Automotive EMC does not require MU, US Military to not require MU. If MU wasn't needed to put a man on the moon it sure as heck isnt needed in washing machines, computers etc. I'm guessing this is more than 10 cents worth! Derek Walton L F Research. From: John Woodgate j...@jmwa.demon.co.uk To: emc-p...@ieee.org Sent: Tue, Aug 10, 2010 11:46 am Subject: Re: Calibration supplier for signal generator with pulse modulation In message c886e31f.841a0%ken.ja...@emccompliance.com, dated Tue, 10 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: Uncertainty for modulation parameters of depth or pulse on-off ratio and time duration? Uncertainty applies to things like field intensity, where the construction of the room or OATS and near field effects combine to provide significant uncertainty. But something easily measured with an o'scope of modest (audio) performance? That is a totally unwarranted extension of the concept. Unfortunately, it isn't. The metrologists have inflicted formal uncertainty assessment on us and it's like death and taxes - always with us. Everything has to have its uncertainty assessed. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user
RE: Calibration supplier for signal generator with pulse modulation
MU is of course the only way of knowing what you do/measure and ultimately test. But if it need to be taken into account…. is another story. But if you do not know where your errors are, I guess you can better stop measuring. In most metrological approaches only the hardware measurement chain is evaluated (antenna-cabling-measuring device), and default value is used for the transfer between EUT through OATS/SAR/FAR. And –as all of you know- the EMC community itself came up with a MU criterion (sort of) for that: the Normalized Site Attenuation with it’s +/4 dB margins (using a well defined simple source) This can be combined with the standard uncertainty of your measurement chain to get a total MU value. Most calcs result in 4-6 dB of MU More can be found in the appropriate part of CISPR 16 (part -4-2) of which I don’t have the exact reference at hand… someone ?? Gert Gremmen ce-test, qualified testing bv Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens lfresea...@aol.com Verzonden: dinsdag 10 augustus 2010 19:07 Aan: j...@jmwa.demon.co.uk; emc-p...@ieee.org Onderwerp: Re: Calibration supplier for signal generator with pulse modulation HI John, just stressing Ken's use of the word unwarranted. I'm personally vehemently opposed to MU in EMC measurements: the reason why is that end to end even 10 dB is a trivial error... Just because the Stds committee says so does not make it warranted. All MU contributes is an academic exercise and lines pockets of individuals/organizations pushing it. We as an EMC community need to push back and say enough already. Our efforts are needed to address more important problems. Just for the record, Automotive EMC does not require MU, US Military to not require MU. If MU wasn't needed to put a man on the moon it sure as heck isnt needed in washing machines, computers etc. I'm guessing this is more than 10 cents worth! Derek Walton L F Research. From: John Woodgate j...@jmwa.demon.co.uk To: emc-p...@ieee.org Sent: Tue, Aug 10, 2010 11:46 am Subject: Re: Calibration supplier for signal generator with pulse modulation In message c886e31f.841a0%ken.ja...@emccompliance.com, dated Tue, 10 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: Uncertainty for modulation parameters of depth or pulse on-off ratio and time duration? Uncertainty applies to things like field intensity, where the construction of the room or OATS and near field effects combine to provide significant uncertainty. But something easily measured with an o'scope of modest (audio) performance? That is a totally unwarranted extension of the concept. Unfortunately, it isn't. The metrologists have inflicted formal uncertainty assessment on us and it's like death and taxes - always with us. Everything has to have its uncertainty assessed. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org
Re: Calibration supplier for signal generator with pulse modulation
HI John, just stressing Ken's use of the word unwarranted. I'm personally vehemently opposed to MU in EMC measurements: the reason why is that end to end even 10 dB is a trivial error... Just because the Stds committee says so does not make it warranted. All MU contributes is an academic exercise and lines pockets of individuals/organizations pushing it. We as an EMC community need to push back and say enough already. Our efforts are needed to address more important problems. Just for the record, Automotive EMC does not require MU, US Military to not require MU. If MU wasn't needed to put a man on the moon it sure as heck isnt needed in washing machines, computers etc. I'm guessing this is more than 10 cents worth! Derek Walton L F Research. From: John Woodgate j...@jmwa.demon.co.uk To: emc-p...@ieee.org Sent: Tue, Aug 10, 2010 11:46 am Subject: Re: Calibration supplier for signal generator with pulse modulation In message c886e31f.841a0%ken.ja...@emccompliance.com, dated Tue, 10 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: Uncertainty for modulation parameters of depth or pulse on-off ratio and time duration? Uncertainty applies to things like field intensity, where the construction of the room or OATS and near field effects combine to provide significant uncertainty. But something easily measured with an o'scope of modest (audio) performance? That is a totally unwarranted extension of the concept. Unfortunately, it isn't. The metrologists have inflicted formal uncertainty assessment on us and it's like death and taxes - always with us. Everything has to have its uncertainty assessed. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
Regardless of what has been done, it is still technically unwarranted. Ken Javor Phone: (256) 650-5261 From: John Woodgate j...@jmwa.demon.co.uk Date: Tue, 10 Aug 2010 17:46:08 +0100 To: emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation In message c886e31f.841a0%ken.ja...@emccompliance.com, dated Tue, 10 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: Uncertainty for modulation parameters of depth or pulse on-off ratio and time duration? Uncertainty applies to things like field intensity, where the construction of the room or OATS and near field effects combine to provide significant uncertainty. But something easily measured with an o'scope of modest (audio) performance? That is a totally unwarranted extension of the concept. Unfortunately, it isn't. The metrologists have inflicted formal uncertainty assessment on us and it's like death and taxes - always with us. Everything has to have its uncertainty assessed. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
In message c886e31f.841a0%ken.ja...@emccompliance.com, dated Tue, 10 Aug 2010, Ken Javor ken.ja...@emccompliance.com writes: Uncertainty for modulation parameters of depth or pulse on-off ratio and time duration? Uncertainty applies to things like field intensity, where the construction of the room or OATS and near field effects combine to provide significant uncertainty. But something easily measured with an o'scope of modest (audio) performance? That is a totally unwarranted extension of the concept. Unfortunately, it isn't. The metrologists have inflicted formal uncertainty assessment on us and it's like death and taxes - always with us. Everything has to have its uncertainty assessed. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
Uncertainty for modulation parameters of depth or pulse on-off ratio and time duration? Uncertainty applies to things like field intensity, where the construction of the room or OATS and near field effects combine to provide significant uncertainty. But something easily measured with an o'scope of modest (audio) performance? That is a totally unwarranted extension of the concept. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com Date: Tue, 10 Aug 2010 08:55:27 -0700 To: Ken Javor ken.ja...@emccompliance.com, Untitled emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation Is there an acceptable method in any immunity standards, or the tolerance specified anywhere for checking the modulation? You need to come up with an uncertainty number if you are performing a compliance test. It should be pretty painful if you are not a ISO 17025 calibration laboratory. OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Tuesday, August 10, 2010 9:39 AM To: Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Amplitude and pulse modulation parameters are adequately checked with a calibrated o'scope. And even frequency could be checked with your EMI receiver, assuming it is calibrated. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com Date: Tue, 10 Aug 2010 08:30:17 -0700 To: Untitled emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation The amplitude of signal source may not need calibration because you calibrate the field at the end with calibrated probes. You should at least check or get the signal generator calibrated if your verification procedure is not checking (characterizing) the modulation. EN 61000-4-3 gives some hints about amplitude modulation but the other modulation types can be difficult to measure (Pulse, burst, phase etc.) OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Tuesday, August 10, 2010 7:05 AM To: Wendy Nya; Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Why would the signal source need calibration? Normally, it is the signal measurement devices that require calibration. Further, this signal source likely requires some amplification in order to provide the required signal for EMI testing, so that it is the amplified output which must be measured, not the signal generator itself. Ken Javor Phone: (256) 650-5261 From: Wendy Nya wendy...@yahoo.com Date: Tue, 10 Aug 2010 01:23:29 -0700 (PDT) To: emc-p...@ieee.org Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org
RE: Calibration supplier for signal generator with pulse modulation
Is there an acceptable method in any immunity standards, or the tolerance specified anywhere for checking the modulation? You need to come up with an uncertainty number if you are performing a compliance test. It should be pretty painful if you are not a ISO 17025 calibration laboratory. OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Tuesday, August 10, 2010 9:39 AM To: Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Amplitude and pulse modulation parameters are adequately checked with a calibrated o'scope. And even frequency could be checked with your EMI receiver, assuming it is calibrated. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com Date: Tue, 10 Aug 2010 08:30:17 -0700 To: Untitled emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation The amplitude of signal source may not need calibration because you calibrate the field at the end with calibrated probes. You should at least check or get the signal generator calibrated if your verification procedure is not checking (characterizing) the modulation. EN 61000-4-3 gives some hints about amplitude modulation but the other modulation types can be difficult to measure (Pulse, burst, phase etc.) OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Tuesday, August 10, 2010 7:05 AM To: Wendy Nya; Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Why would the signal source need calibration? Normally, it is the signal measurement devices that require calibration. Further, this signal source likely requires some amplification in order to provide the required signal for EMI testing, so that it is the amplified output which must be measured, not the signal generator itself. Ken Javor Phone: (256) 650-5261 From: Wendy Nya wendy...@yahoo.com Date: Tue, 10 Aug 2010 01:23:29 -0700 (PDT) To: emc-p...@ieee.org Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org
Re: Calibration supplier for signal generator with pulse modulation
Amplitude and pulse modulation parameters are adequately checked with a calibrated o'scope. And even frequency could be checked with your EMI receiver, assuming it is calibrated. Ken Javor Phone: (256) 650-5261 From: Deniz Demirci deniz.demi...@ntscorp.com Date: Tue, 10 Aug 2010 08:30:17 -0700 To: Untitled emc-p...@ieee.org Conversation: Calibration supplier for signal generator with pulse modulation Subject: RE: Calibration supplier for signal generator with pulse modulation The amplitude of signal source may not need calibration because you calibrate the field at the end with calibrated probes. You should at least check or get the signal generator calibrated if your verification procedure is not checking (characterizing) the modulation. EN 61000-4-3 gives some hints about amplitude modulation but the other modulation types can be difficult to measure (Pulse, burst, phase etc.) OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Tuesday, August 10, 2010 7:05 AM To: Wendy Nya; Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Why would the signal source need calibration? Normally, it is the signal measurement devices that require calibration. Further, this signal source likely requires some amplification in order to provide the required signal for EMI testing, so that it is the amplified output which must be measured, not the signal generator itself. Ken Javor Phone: (256) 650-5261 From: Wendy Nya wendy...@yahoo.com Date: Tue, 10 Aug 2010 01:23:29 -0700 (PDT) To: emc-p...@ieee.org Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc
RE: Calibration supplier for signal generator with pulse modulation
The amplitude of signal source may not need calibration because you calibrate the field at the end with calibrated probes. You should at least check or get the signal generator calibrated if your verification procedure is not checking (characterizing) the modulation. EN 61000-4-3 gives some hints about amplitude modulation but the other modulation types can be difficult to measure (Pulse, burst, phase etc.) OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Tuesday, August 10, 2010 7:05 AM To: Wendy Nya; Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Why would the signal source need calibration? Normally, it is the signal measurement devices that require calibration. Further, this signal source likely requires some amplification in order to provide the required signal for EMI testing, so that it is the amplified output which must be measured, not the signal generator itself. Ken Javor Phone: (256) 650-5261 From: Wendy Nya wendy...@yahoo.com Date: Tue, 10 Aug 2010 01:23:29 -0700 (PDT) To: emc-p...@ieee.org Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
Given your list of equipment, the only thing you should need to calibrate about the signal source is the frequency accuracy. Ken Javor Phone: (256) 650-5261 From: Wendy Nya wendy...@yahoo.com Date: Tue, 10 Aug 2010 06:17:17 -0700 (PDT) To: Ken Javor ken.ja...@emccompliance.com, Untitled emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation In Radiated Immunity, the amplifier output is not calibrated. Rather it is the signal generator, power meter, power heads and field probe. - Original Message From: Ken Javor ken.ja...@emccompliance.com To: Wendy Nya wendy...@yahoo.com; Untitled emc-p...@ieee.org Sent: Tue, 10 August, 2010 21:04:33 Subject: Re: Calibration supplier for signal generator with pulse modulation Why would the signal source need calibration? Normally, it is the signal measurement devices that require calibration. Further, this signal source likely requires some amplification in order to provide the required signal for EMI testing, so that it is the amplified output which must be measured, not the signal generator itself. Ken Javor Phone: (256) 650-5261 From: Wendy Nya wendy...@yahoo.com Date: Tue, 10 Aug 2010 01:23:29 -0700 (PDT) To: emc-p...@ieee.org Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
In Radiated Immunity, the amplifier output is not calibrated. Rather it is the signal generator, power meter, power heads and field probe. From: Ken Javor ken.ja...@emccompliance.com To: Wendy Nya wendy...@yahoo.com; Untitled emc-p...@ieee.org Sent: Tue, 10 August, 2010 21:04:33 Subject: Re: Calibration supplier for signal generator with pulse modulation Why would the signal source need calibration? Normally, it is the signal measurement devices that require calibration. Further, this signal source likely requires some amplification in order to provide the required signal for EMI testing, so that it is the amplified output which must be measured, not the signal generator itself. Ken Javor Phone: (256) 650-5261 From: Wendy Nya wendy...@yahoo.com Date: Tue, 10 Aug 2010 01:23:29 -0700 (PDT) To: emc-p...@ieee.org Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: Calibration supplier for signal generator with pulse modulation
Why would the signal source need calibration? Normally, it is the signal measurement devices that require calibration. Further, this signal source likely requires some amplification in order to provide the required signal for EMI testing, so that it is the amplified output which must be measured, not the signal generator itself. Ken Javor Phone: (256) 650-5261 From: Wendy Nya wendy...@yahoo.com Date: Tue, 10 Aug 2010 01:23:29 -0700 (PDT) To: emc-p...@ieee.org Subject: Calibration supplier for signal generator with pulse modulation Dear All, I am looking for a calibration supplier that can provide accredited service for AR SG6000. It has built-in pulse modulation option (for Radiated Immunity use). By the way - Is anyone using this model? It seems to be OEM from Agilent (it came in an agilent box) but the equipment is marked AR and works with Agilent N5181A driver. Agilent is saying that it is not able to provide accredited calibration service for this model. Thanks Regards, Wendy Nya - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
