http://www.ieee-pses.org/symposium http://www.emc2004.org/ -------------------------------------------------- Beware of transient limiter action as well when doing conducted measurements. If a signal outside the frequency band of interest, say <150kHz, is larger than the threshold of the limiter circuit, the result will be in-band harmonics which are signals not originating from the EUT. Ralph McDiarmid, AScT Compliance Engineering Group Xantrex Technology Inc.
From: [email protected] mailto:[email protected]] On Behalf Of Ken Javor Sent: August 5, 2004 1:15 PM To: Michael Taylor; [email protected] Subject: Re: Pre-Amp overload http://www.ieee-pses.org/symposium http://www.emc2004.org/ -------------------------------------------------- I agree that if you are looking at raw data knowing the 1 dB compression point and the pre amp gain is all that is necessary, as long as you are looking at the entire spectrum on the analyzer. If the overloading signal is not displayed, knowing the 1 dB compression point isn't helpful. Another problem is if the displayed data has been adjusted for a transducer factor. Then the 1 dB compression point info is difficult to assess by simply eyeing the display. From: Michael Taylor <[email protected]> List-Post: [email protected] Date: Thu, 5 Aug 2004 12:33:22 -0600 To: [email protected] Subject: Pre-Amp overload http://www.ieee-pses.org/symposium http://www.emc2004.org/ -------------------------------------------------- A much easier way is to determine the 1db compression point of the unit. That can be done with a signal generator and your analyzer at several points. Even easier if you have a tracking generator. 0 (zero)-dbm is +107dbuV. Most commercial preamps will handle at least 0dbm. Most of the octave units I have worked with will handle at least +5dbm max input. If you are measuring signals that high, you have serious emission issues to deal with. If you still are concerned about overload, a 3db pad is a good place to start. Just remember the S/NAN issue. Regards to all. Michael Taylor PE, NCE Sr EMC Eng. Hach business group Danaher Corp. ------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. IEEE PSES Main Website: http://www.ieee-pses.org/ To post a message send your e-mail to [email protected] Instructions for use of the list server: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: [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: http://www.ieeecommunities.org/emc-pstc ------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. IEEE PSES Main Website: http://www.ieee-pses.org/ To post a message send your e-mail to [email protected] Instructions for use of the list server: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: [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: http://www.ieeecommunities.org/emc-pstc ------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. IEEE PSES Main Website: http://www.ieee-pses.org/ To post a message send your e-mail to [email protected] Instructions for use of the list server: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: [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: http://www.ieeecommunities.org/emc-pstc
