In message <[email protected]>, dated Wed, 14 Mar 2007, Ralph McDiarmid <[email protected]> writes:
>I have two questions for the group concerning detection circuits used >on spectrum analyzers: > >1. With no other changes to gain, bandwidth or transducer factors, >would an AVG detector provide a lower noise floor than a QP detector? Well, it depends on the character (amplitude probability distribution) of the noise, but normally, yes, it does. 'Infinitely clipped' noise would probably produce the same reading in both modes. > >2. Which of these two detectors has the longer time-constant (charge & >discharge) It depends if they are designed to meet the CISPR 16/EN 55016 standard or some other specification. The QP detector normally has a charge time-constant of a few milliseconds and a discharge time-constant of about 1 second. But an average detector may, in general, have a long averaging time. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk There are benefits from being irrational - just ask the square root of 2. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
