http://www.ieee-pses.org/symposium http://www.emc2004.org/ -------------------------------------------------- QP is 1 ms attack and 1 second decay, is it not? Dave Cuthbert Micron Technology
From: [email protected] mailto:[email protected]] On Behalf Of Bob Richards Sent: Thursday, August 05, 2004 7:06 AM To: [email protected] Subject: Re: Question on Quasi-Peak vs. Peak vs. Average Measurements http://www.ieee-pses.org/symposium http://www.emc2004.org/ -------------------------------------------------- Robert, Good morning! You are correct, for a CW narrowband signal, the peak, QP and average should be very close to the same. For broadband signals I don't think you can use a rule-of-thumb for how much the average measurement should be below the peak, since that depends entirely on the nature of the signal being measured. You can possibly have a rule-of-thumb for a type of signal always coming from the same product, but even that would not be a good assumption to make. Both QP and average measurements are post-detection filters. QP can be thought of as a peak-weighted average measurement, with a fast charge constant and a slow discharge constant. I believe an average measurement will have the same charge/discharge time constants. So, peak will always be the highest and average will always be the lowest. Bob Richards Square D. [email protected] wrote: http://www.ieee-pses.org/symposium http://www.emc2004.org/ -------------------------------------------------- Good Morning Ladies and Gentlemen (well morning for me anyway I guess it depends on where you are!), I have a friend that is questioning his measurements for Radiated Emissions per CISPR 25 Method in his lab. Certain OEM's require us to measure Peak, QP, and Average all at once. The results he shows are Peak being the highest measurement, then Quasi-Peak, with Average being the lowest. I explained to him this is the same type of results I obtain in my lab and I am an accredited and correlated lab! Regardless of my explanations he is still not sure, I figured somebody on this list can help give a very clear explanation. I basically told him that in my experience and knowledge that for Narrowband Measurements the three should be very close to the same. In broadband the general rule I remember is; Peak is the highest measurement Peak - 6dB = average measurement If someone could provide a better explanation to how the three types of measurements compare I would appreciate it, this is why I became an engineer and not a teacher! Thank you in advance. Rob Kado EMC Engineer VWS - Auburn Hills, USA Tel: 248-340-3828 / Fax: 248-340-3316 Internal Location 3M2 ------------------------------------------- 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
