It's been a long time since I did military-style testing -- TEMPEST in the 1980's -- but it seemed to me then that no great care was taken to control cable common-mode impedance. The environment INSIDE the chamber was as unrealistic as one might care to get, and no attempt was made to control or modify chamber resonances. A reverberant chamber so dominates radiated tests* conducted in it that deviation as a result of signal line filters may be unnoticeable from one chamber to the next.
Realistically, any filtering used has to conform to the requirements of the signal being filtered, as would an actual installation. This makes it possible to use for testing. However... is use of filters in "real-life" ruled out when testing has been done without them? The ideal filter would be, I suppose, one whose impedance simulates in both common and differential modes the infinite conductor of myth and theory, with no signal reflected. This seems what the European absorbing clamp attempts to provide, and might be useful here. *I've seen a reverberant chamber dominate _conducted_ tests, too. A Part 15 test had to be done outside. Cortland 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
