When it comes to MU and EMC, one should never confuse "ignorance" with "apathy". : ) Bob Heller St. Paul, MN 55107-1208 Tel: 651- 778-6336 Fax: 651-778-6252
> ========================================================================= > > From: > > Ken Javor <[email protected]> > > To: > > Untitled <[email protected]> > > Date: > > 08/11/2010 12:04 PM > > Subject: > > Re: Calibration supplier for signal generator with pulse modulation > > Sent by: > > <[email protected]> > > 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 <[email protected]> > Reply-To: <[email protected]> > Date: Wed, 11 Aug 2010 09:50:21 -0700 > To: <[email protected]>, <[email protected]>, <[email protected]> > 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’tmatter.” > > 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: [email protected] [mailto:[email protected]] On Behalf Of > [email protected] > Sent: Wednesday, August 11, 2010 9:00 AM > To: [email protected]; [email protected] > 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. > > -----Original Message----- > From: Deniz Demirci <[email protected]> > To: Untitled <[email protected]> > 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:[email protected] > > > > > web: http://www.ntscorp.com/about/locations > > > > > > > > > > > > > > > > > > > > -----Original Message----- > > > > > From: [email protected] [mailto:[email protected] <mailto:[email protected]?> > ] 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 <[email protected]> > > > > > > Reply-To: <[email protected]> > > > > > > Date: Wed, 11 Aug 2010 08:27:34 -0400 > > > > > > To: emc-pstc <[email protected]> > > > > > > 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 <[email protected]> > > > > > >> To: <[email protected]> > > > > > >> 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 > > > > > > <[email protected]> > > > > > > > > > > > > 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 <[email protected]> > > > > > > Mike Cantwell <[email protected]> > > > > > > > > > > > > For policy questions, send mail to: > > > > > > Jim Bacher: <[email protected]> > > > > > > David Heald: <[email protected]> > > > > > > > > > > - > > > > > ---------------------------------------------------------------- > > > > > 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 <[email protected]> > > > > > > > > > > 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 <[email protected]> > > > > > Mike Cantwell <[email protected]> > > > > > > > > > > For policy questions, send mail to: > > > > > Jim Bacher: <[email protected]> > > > > > David Heald: <[email protected]> > > > > > > > > > > - > > > > > ---------------------------------------------------------------- > > > > > 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 > > > > > <[email protected]> > > > > > > > > > > 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 <[email protected]> > > > > > Mike Cantwell <[email protected]> > > > > > > > > > > For policy questions, send mail to: > > > > > Jim Bacher: <[email protected]> > > > > > David Heald: <[email protected]> > > > > > - > ---------------------------------------------------------------- > 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 <[email protected]> > > 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 <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > - > ---------------------------------------------------------------- > 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 <[email protected]> > > 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 <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > - > ---------------------------------------------------------------- > 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 < > [email protected]> > > 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 <[email protected]> > Mike Cantwell <[email protected]> > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> - 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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
