I read in !emc-pstc that Colgan, Chris <[email protected]> wrote (in <AE0F4BD08FEAD211895900805FE67B1FD6CAF1@CAT>) about 'performance criterion A', on Tue, 18 Sep 2001:
>According to EN50082-1, no degradation of performance below a performance >level specified by the manufacturer is allowed whereas EN55020 gives a clear >cut wanted/unwanted signal to noise ratio of 40dB. Well, not quite, but your intention is clear. > Now say my audio >amplifier specs give a signal to noise ratio of x dB but also state in a >footnote that this signal to noise ratio may be degraded in the presence of >a modulated RF field (you can see where I'm going). Could my audio >amplifier then demodulate the 1kHz tone in the conducted and radiated >immunity tests and pass performance criterion A? No. The requirement in the product standard EN 55020 supersedes the apparently eminently more reasonable one in the Generic. This is partly because EN 55020 is a very old standard, from the days when everything was more prescriptive, and partly because it concerns consumer products, where the purchaser is not assumed to understand a manufacturer's technical specification of the degradation. In any case, a signal-to-interference ratio of 40 dB is pretty dismal in the context of a hi-fi amplifier with a signal-to-noise ratio of 90 dB or more. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! ------------------------------------------- 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
