Ed I didn't say the US DoD would buy it :). Out of interest, does the US DoD operate an Urgent Operation Requirement or similar short-cutting procurement process, as done by UK MoD, that allows them to bring stuff into use that has known, acceptable and mitigated EMC performance, but does not meet a blanket (and possibly irrelevant) "DC to daylight" emissions/immunity level?
MIL-STD EMC and Environmental qualifications are accepted by a number of customers world wide, other than DoD, and there are military radios that don't pass CE106 (indeed, given constrains of their size, could not pass it) being sold quite successfully. Where there is an unusual technology, or unclear application of the standard, I would expect there to be a discussion between manufacturer and end customer as to what was actually required and how compliance would be demonstrated. Spurious Emission limits are normally expressed with regard to a specific measurement bandwidth, rather than product related bandwidth because they are really there to limit noise in the radio spectrum - without particularly caring what caused them. There are typically higher limits for devices operating in licensed bands than unlicensed because there is some control over the use of the former and they are typically present in lower density (devices per unit of area). Regards Charlie From: Ed Price [mailto:[email protected]] Sent: 09 August 2012 20:38 To: [email protected] 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:[mailto:[email protected]]> Sent: Thursday, August 09, 2012 1:26 AM To: [email protected]<mailto:[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:[email protected]]<mailto:[mailto:[email protected]]> Sent: 07 August 2012 00:21 To: [email protected]<mailto:[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: [email protected]<mailto:[email protected]> [mailto:[email protected]]<mailto:[mailto:[email protected]]> On Behalf Of Airy, Chad Sent: Monday, August 06, 2012 6:44 PM To: [email protected]<mailto:[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]<mailto:[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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[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]<mailto:[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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[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]<mailto:[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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[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]<mailto:[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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[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]>
