Ralph:
I used the ancient HP-85869PC data acquisition software, and HP (being conservative) used a 1 Hz RBW for implementing an Average detector. They did this to extend the HP-8566B’s capabilities to commercial EMI testing. (For Quasi Peak, they needed an external filter and detector box that was inserted in the 8566B’s IF chain.) However, the 461 detector is always supposed to be a Peak detector. (Except for CS101, where the limit is expressed in terms of Vrms. OTOH, almost everyone uses an oscilloscope to monitor this level, so…) Ed Price El Cajon, CA USA From: [email protected] [mailto:[email protected]] Sent: Thursday, August 09, 2012 1:52 PM To: [email protected] Subject: Re: [PSES] MIL STD 461E NECESSARY BANDWIDTH Hi Ed, I would have thought so too, unless 461 has an AVG limit line, in which case I'd use an average detector for both. BTW, we've found that a VBW of 10Hz does a reasonable job of emulating the response of an average detector defined in CISPR 16. _______________________________________________________________________________ Ralph McDiarmid | Schneider Electric | Solar Business | CANADA | Regulatory Compliance Engineering Phone: +1-604-422-2622 | e-mail: <mailto:[email protected]> [email protected] | Site: <http://www.schneider-electric.com/> www.schneider-electric.com | Address: 3700 Gilmore Way, Burnaby, BC, V5G4M1 From: Ed Price <[email protected]> To: [email protected] Date: 08/09/2012 12:40 PM Subject: Re: [PSES] MIL STD 461E NECESSARY BANDWIDTH _____ Charlie: The USA DoD procurement system uses a detailed contract to legally bind a vendor to a number of conditions, and in the EMC area, the successful performance of MIL-STD-461F is typical. The contract will call out which specific Test Methods (including variations) are applicable, so if CE106 is in the contract, believe me, it is mandatory. True, the early 461 was just taking an educated whack at controlling intentional emissions to nothing more than was reasonable and economical to achieve. There was little justification to why 5% was better than 7%, other than the ancient relationship to half the number of allocated fingers. (BTW, can you imagine a world in which 7 fingers or toes per hand or foot gave rise to a base 14 numerical system?) Lastly, why would you use a different RBW to measure the fundamental versus the spurious emissions? I would think that the only way to accurately measure the peak of a spurious was the same way that you measured the peak of the fundamental. Ed Price El Cajon, CA USA From: Charlie Blackham [ <mailto:[email protected]> mailto:[email protected]] Sent: Thursday, August 09, 2012 1:26 AM To: [email protected] Subject: Re: [PSES] MIL STD 461E NECESSARY BANDWIDTH ETSI standards typically define “Spurious Emissions” as being those removed from cF by >250% of the necessary bandwidth. Emissions within this region are typically covered by Spectral Mask and Occupied Bandwidth requirements, both of which are typically measured using much lower RBWs than used for Spurious Emissions so that accurate measurements can be obtained. I’m might be talking out of my hat now, but when MIL-STD-461 was first written way back when, I’m sure that they were really only thinking in terms of AM/FM modulation - 40 MHz wide OFDM and 1GHz wide FMCW devices weren’t probably envisaged. Since, in my experience, CE106 isn’t actually Mandatory for selling a product, I would do the test in a way that seems reasonable for the operation of your product, document what you’ve done and why, and discuss/explain to customers as required. You might want to have a look at CEPT/ERC/REC 74-01 and associated documents Regards Charlie From: Mazzola, Santo (US SSA) <mailto:[mailto:[email protected]]> [mailto:[email protected]] Sent: 07 August 2012 00:21 To: <mailto:[email protected]> [email protected] Subject: Re: [PSES] MIL STD 461E NECESSARY BANDWIDTH Airy, In MIL-STD-461F they changed the language of the exception, It now reads: The transmit mode portion of this requirement is not applicable within the bandwidth of the EUT transmitted signal or within ±5 percent of the fundamental frequency, whichever is larger. So if the necessary bandwidth is greater then +/- 5% it is still excluded. Speaking in generalities, the necessary bandwidth of whatever kind of transmitter it is, probably has some kind of Spectral mask requirement that is not a MIL-STD-461 requirement. The spurious emissions requirements of CE106 cannot begin until after the necessary bandwidth ends. Hope that helps. Sandy (Santo) Mazzola EMC Engineer BAE Systems Inc From: <mailto:[email protected]> [email protected] <mailto:[mailto:[email protected]]> [mailto:[email protected]] On Behalf Of Airy, Chad Sent: Monday, August 06, 2012 6:44 PM To: <mailto:[email protected]> [email protected] Subject: MIL STD 461E NECESSARY BANDWIDTH Greetings, Greetings to all, this is my first post to the list. My question deals with the Applicability paragraph of CE106. How does one apply the +/-5% non-applicability rule when the necessary bandwidth exceeds 10% of the fundamental frequency by a fair margin? Quoting the standard: ”The transmit mode portion of this requirement is not applicable within the EUT necessary bandwidth and within ±5 percent of the fundamental frequency.” The case I am referring to is real. However, to prevent exposure of proprietary information, I will use a hypothetical example: An airborne synthetic aperture radar having a fixed nominal chirp bandwidth of 1500 MHz at a center frequency of 15 GHz, illuminates a designated area on the ground. The radar fly’s by the area, capturing multiple images, each from different depression and squint angles. During the transit of the imaging path, the radar center frequency and chirp bandwidth are gradually shifted for the purpose of improving the image quality. The resulting envelope of occupied (chirp BW + center freq shift) is 2000 MHz. Chad Airy SM, IEEE EMC SOCIETY Senior RF Engineer EMC Lab Manager General Atomics - RSG OFC. 858.762.6853 - ---------------------------------------------------------------- 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. 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 email has been scanned by the Symantec Email Security.cloud service. ______________________________________________________________________ - ---------------------------------------------------------------- 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. 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]>
