>-----Original Message----- >From: Low, Aaron S [mailto:aaron.s....@lmco.com] >Sent: Wednesday, March 19, 2003 11:49 AM >To: emc-p...@majordomo.ieee.org >Subject: RE: antenna port conducted emissions > > > >I'd like to thank all those who replied so far. > >According to MIL-STD-462D: > >4.9.2 Operating frequencies for spread spectrum equipment. >Operating frequency requirements for two major types of spread spectrum >equipment shall be as > follows: > a. Frequency hopping. Measurements shall be performed >with the EUT >utilizing a hop set > which contains a minimum of 30% of the total possible >frequencies. This hop set shall > be divided equally into three segments at the >low, mid, and >high end of the EUT's > operational frequency range. > b. Direct sequence. Measurements shall be performed with the EUT >processing data at the > highest possible data transfer rate. > >Can I interpret this section to mean that when scanning for emissions, >standard MIL-STD scanning methods apply? > >Aaron > > Aaron S. Low > Systems Engineer >Naval Electronics and Surveillance Systems >EP5 D5 MD45 Syracuse, NY 13221-4840 >Phone: (315) 456-1203 Fax: (315) 456-0509 >L
I interpret 4.9.2.a as trying to ensure that you are not playing tricks with the selection of frequencies. For instance, at the low end of your hop range, your circuit might generate higher harmonic content, so you decide to choose a hop set that's all in the upper 1/3 of the range. No, uh-uh, not prudent, shouldn't do that. If by "methods", you mean scanning speed, in MHz per second, then remember that Paragraph 4.3.10.3.1, Table II is only a set of maximum speed limits. Notice that 4.3.10.3.3 says "For equipment that operates such that the potential emissions are produced at only infrequent intervals, times for frequency scanning shall be increased as necessary to capture any emissions." As I said earlier, you may have to scan much slower than the speed limit. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
