Re: Calculating/predicting Quasi-peak of a single pulse
John- The general transfer function for a mass-spring-damp (as the mechanical meter) (or R-L-C) is of the form: (s + 2dw)/(s^2 + 2dws + w^2) where w = natural frequency of system and d = damping ratio (dimensionless) For critical damping as per the USA definition, d = 1, and there are two real poles on top of each other at -dw (or -w, since d = 1). For critical damping as defined for the meter used in the quasi-peak measurement, d = 0.707. This produces two complex poles at -dw +- jw*sqrt(1 - d^2), with the real and imaginary parts having the same magnitude. Thus lines drawn from the origin to the poles lie at angles 135 deg and 225 degrees, or +-45 degrees off of the negative real axis. I realize this is a bit murky, but I hope it works. At the time I was reviewing all of this, the "legacy issues" were not stated explicitly, so I was confronted with calculated responses that did not exactly match measurements, and also additional circuitry in the electronic quasi-peak measurement box that I could not explain. Perhaps this is now clearly stated. Don Borowski Schweitzer Engineering Labs Pullman, WA John Woodgate wrote on 04/21/2004 12:28:29 PM: > I read in !emc-pstc that don_borow...@selinc.com wrote (in 7eea869-on88256e7d.00508cf6-88256e7d.00523...@selinc.com>) about > 'Calculating/predicting Quasi-peak of a single pulse' on Wed, 21 Apr > 2004: > > >The (mechanical) indicator issue is a bit more complex than Mr. Gremmen > >states. The indicator is to be "critically damped", as the definition is > >understood in Europe, which is that the transfer function (electrical input > >to mechanical output) has two poles in the left half-plane, 45 degrees off > >of the real axis. In this definition, there is some overshoot to a step > >function. Note that this is different than the definition as usually > >understood in the USA, where it is taken to mean that there are two poles > >on top of each other in the left half plane, on the real axis. This > >condition gives the quickest response to a step input without any > >overshoot. > > Could you please give the s-plane transfer functions that show the > difference between the EU and US terminology? > > > >Even with this, there will still be a few tens of a dB difference in the > >calculated vs. actual response. Early in the development by HP of a > >quasi-peak adaptor for their spectrum analyzer, they found that there was > >some discrepancy between the response of their electronic metering circuit > >and the indication given by the meter on the Rhode & Schwarz quasi-peak box > >(which was industry standard at the time). HP carefully measured the actual > >response of the mechanical meter and added some circuitry to mimic it. > > This is a well-known 'legacy issue', where the arcane properties of > pointer instruments have been assimilated into the specifications of > measuring devices. Digital indicators have to be 'kludged' to simulate > the 'defects' of the mechanical instruments. > -- > Regards, John Woodgate, OOO - Own Opinions Only. > The good news is that nothing is compulsory. > The bad news is that everything is prohibited. > http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ieee-pses.org/ > > 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: emc_p...@symbol.com > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Calculating/predicting Quasi-peak of a single pulse
Whoops! At the beginning of the second paragraph I meant to say "... a few TENTHS of a dB ..." Don Borowski Schweitzer Engineering Labs Pullman, WA I wrote on 04/21/2004 07:58:18 AM: > I looked at this in detail about 20 years ago. If things haven't changed > since then, this is the rest of the story: > > The (mechanical) indicator issue is a bit more complex than Mr. Gremmen > states. The indicator is to be "critically damped", as the definition is > understood in Europe, which is that the transfer function (electrical input > to mechanical output) has two poles in the left half-plane, 45 degrees off > of the real axis. In this definition, there is some overshoot to a step > function. Note that this is different than the definition as usually > understood in the USA, where it is taken to mean that there are two poles > on top of each other in the left half plane, on the real axis. This > condition gives the quickest response to a step input without any > overshoot. > > Even with this, there will still be a few tens of a dB difference in the > calculated vs. actual response. Early in the development by HP of a > quasi-peak adaptor for their spectrum analyzer, they found that there was > some discrepancy between the response of their electronic metering circuit > and the indication given by the meter on the Rhode & Schwarz quasi-peak box > (which was industry standard at the time). HP carefully measured the actual > response of the mechanical meter and added some circuitry to mimic it. > > Don Borowski > Schweitzer Engineering Labs > Pullman, WA > > > > > "Ing. Gert > Gremmen" >.nl> "Rosenberg, Drew" > Sent by: , > owner-emc-pstc@ma > jordomo.ieee.org cc > > Subject > 04/20/04 12:51 AM RE: Calculating/predicting >Quasi-peak of a single pulse > > Please respond to > "Ing. Gert > Gremmen" > .nl> > > > > > > > > Hi Drew, > > The measurement procedure also includes a time constant of 250 mS for > simulation of the electromechanical analog indicator originally > used to read out the QP value. So your measurement result > will achieve 99% only after 1250 mS > > For repeating pulses the calculation/readout will be correct. > > > Regards, > > Gert Gremmen > Approvals manager > == > ce-test, qualified testing > Member of EMC committee CENELEC/IEC > > + Independent Consultancy Services > + Compliance Testing and Design for CE > + Improvement of product quality and reliability > + Testing services according to: > Electro magnetic Compatibility 89/336/EC > Electrical Safety 73/23/EC > Medical Devices 93/42/EC > Radio & Telecommunication Terminal equipment 99/5/EC > > Website: www.cetest.nl (english) > www.ce-test.nl (dutch) > Phone : +31 10 415 24 26 > Fax :+31 10 415 49 53 > == > > > > -Original Message- > From: owner-emc-p...@majordomo.ieee.org > [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Rosenberg, Drew > Sent: Monday, April 19, 2004 11:00 PM > To: emc-p...@majordomo.ieee.org > Subject: Calculating/predicting Quasi-peak of a single pulse > > > > Hi EMC Gurus, > I have been struggling with something for a while and have > decided that > this is the best place to send my question: > > I would like to better understand how quasi-peak is determined > on a single > pulse of specified duration. From my understanding, Quasi-peak applies an > RC time constant to the pulse. If the pulse length equals 5 times the RC > time constant, then the QP measurement will be roughly 99% of the peak > measurement. > According to CISPR-16-1 Table 1, the charging time constant > specified is 1 > ms. Therefore, according to my understanding, QP should be 99% of peak > measurement at 5ms. > > However, my experiments have given very different results. I > have an > HP8593E spectrum analyzer. In an effort to prove my understanding of > CISPR-16-1's definition of Quasi-peak, I applied a 1 second 900 MHz pulse > to > the spectrum analyzer with QP detection on. This 1 second pulse was > applied > using the pulse trigger of a Marconi 2024 sig gen.
Re: Calculating/predicting Quasi-peak of a single pulse
I read in !emc-pstc that don_borow...@selinc.com wrote (in ) about 'Calculating/predicting Quasi-peak of a single pulse' on Wed, 21 Apr 2004: >The (mechanical) indicator issue is a bit more complex than Mr. Gremmen >states. The indicator is to be "critically damped", as the definition is >understood in Europe, which is that the transfer function (electrical input >to mechanical output) has two poles in the left half-plane, 45 degrees off >of the real axis. In this definition, there is some overshoot to a step >function. Note that this is different than the definition as usually >understood in the USA, where it is taken to mean that there are two poles >on top of each other in the left half plane, on the real axis. This >condition gives the quickest response to a step input without any >overshoot. Could you please give the s-plane transfer functions that show the difference between the EU and US terminology? > >Even with this, there will still be a few tens of a dB difference in the >calculated vs. actual response. Early in the development by HP of a >quasi-peak adaptor for their spectrum analyzer, they found that there was >some discrepancy between the response of their electronic metering circuit >and the indication given by the meter on the Rhode & Schwarz quasi-peak box >(which was industry standard at the time). HP carefully measured the actual >response of the mechanical meter and added some circuitry to mimic it. This is a well-known 'legacy issue', where the arcane properties of pointer instruments have been assimilated into the specifications of measuring devices. Digital indicators have to be 'kludged' to simulate the 'defects' of the mechanical instruments. -- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory. The bad news is that everything is prohibited. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Calculating/predicting Quasi-peak of a single pulse
I looked at this in detail about 20 years ago. If things haven't changed
since then, this is the rest of the story:
The (mechanical) indicator issue is a bit more complex than Mr. Gremmen
states. The indicator is to be "critically damped", as the definition is
understood in Europe, which is that the transfer function (electrical input
to mechanical output) has two poles in the left half-plane, 45 degrees off
of the real axis. In this definition, there is some overshoot to a step
function. Note that this is different than the definition as usually
understood in the USA, where it is taken to mean that there are two poles
on top of each other in the left half plane, on the real axis. This
condition gives the quickest response to a step input without any
overshoot.
Even with this, there will still be a few tens of a dB difference in the
calculated vs. actual response. Early in the development by HP of a
quasi-peak adaptor for their spectrum analyzer, they found that there was
some discrepancy between the response of their electronic metering circuit
and the indication given by the meter on the Rhode & Schwarz quasi-peak box
(which was industry standard at the time). HP carefully measured the actual
response of the mechanical meter and added some circuitry to mimic it.
Don Borowski
Schweitzer Engineering Labs
Pullman, WA
"Ing. Gert
Gremmen"
"Rosenberg, Drew"
Sent by: ,
owner-emc-pstc@ma
jordomo.ieee.org cc
Subject
04/20/04 12:51 AM RE: Calculating/predicting
Quasi-peak of a single pulse
Please respond to
"Ing. Gert
Gremmen"
Hi Drew,
The measurement procedure also includes a time constant of 250 mS for
simulation of the electromechanical analog indicator originally
used to read out the QP value. So your measurement result
will achieve 99% only after 1250 mS
For repeating pulses the calculation/readout will be correct.
Regards,
Gert Gremmen
Approvals manager
==
ce-test, qualified testing
Member of EMC committee CENELEC/IEC
+ Independent Consultancy Services
+ Compliance Testing and Design for CE
+ Improvement of product quality and reliability
+ Testing services according to:
Electro magnetic Compatibility 89/336/EC
Electrical Safety 73/23/EC
Medical Devices 93/42/EC
Radio & Telecommunication Terminal equipment 99/5/EC
Website: www.cetest.nl (english)
www.ce-test.nl (dutch)
Phone : +31 10 415 24 26
Fax :+31 10 415 49 53
==
From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Rosenberg, Drew
Sent: Monday, April 19, 2004 11:00 PM
To: emc-p...@majordomo.ieee.org
Subject: Calculating/predicting Quasi-peak of a single pulse
Hi EMC Gurus,
I have been struggling with something for a while and have
decided that
this is the best place to send my question:
I would like to better understand how quasi-peak is determined
on a single
pulse of specified duration. From my understanding, Quasi-peak applies an
RC time constant to the pulse. If the pulse length equals 5 times the RC
time constant, then the QP measurement will be roughly 99% of the peak
measurement.
According to CISPR-16-1 Table 1, the charging time constant
specified is 1
ms. Therefore, according to my understanding, QP should be 99% of peak
measurement at 5ms.
However, my experiments have given very different results. I
have an
HP8593E spectrum analyzer. In an effort to prove my understanding of
CISPR-16-1's definition of Quasi-peak, I applied a 1 second 900 MHz pulse
to
the spectrum analyzer with QP detection on. This 1 second pulse was
applied
using the pulse trigger of a Marconi 2024 sig gen
RE: Calculating/predicting Quasi-peak of a single pulse
Hi Drew, The measurement procedure also includes a time constant of 250 mS for simulation of the electromechanical analog indicator originally used to read out the QP value. So your measurement result will achieve 99% only after 1250 mS For repeating pulses the calculation/readout will be correct. Regards, Gert Gremmen Approvals manager == ce-test, qualified testing Member of EMC committee CENELEC/IEC + Independent Consultancy Services + Compliance Testing and Design for CE + Improvement of product quality and reliability + Testing services according to: Electro magnetic Compatibility 89/336/EC Electrical Safety 73/23/EC Medical Devices 93/42/EC Radio & Telecommunication Terminal equipment 99/5/EC Website: www.cetest.nl (english) www.ce-test.nl (dutch) Phone : +31 10 415 24 26 Fax :+31 10 415 49 53 == From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Rosenberg, Drew Sent: Monday, April 19, 2004 11:00 PM To: emc-p...@majordomo.ieee.org Subject: Calculating/predicting Quasi-peak of a single pulse Hi EMC Gurus, I have been struggling with something for a while and have decided that this is the best place to send my question: I would like to better understand how quasi-peak is determined on a single pulse of specified duration. From my understanding, Quasi-peak applies an RC time constant to the pulse. If the pulse length equals 5 times the RC time constant, then the QP measurement will be roughly 99% of the peak measurement. According to CISPR-16-1 Table 1, the charging time constant specified is 1 ms. Therefore, according to my understanding, QP should be 99% of peak measurement at 5ms. However, my experiments have given very different results. I have an HP8593E spectrum analyzer. In an effort to prove my understanding of CISPR-16-1's definition of Quasi-peak, I applied a 1 second 900 MHz pulse to the spectrum analyzer with QP detection on. This 1 second pulse was applied using the pulse trigger of a Marconi 2024 sig gen. To my surprise, QP did not equal peak until about 500ms. Does anyone know why I am getting such different results than what I had predicted? I have data and analyzer pics if anyone thinks that they would help. I have been told that attachments are not good for list servers, so please let me know if you would like to see them. Regards, Drew Rosenberg Regulatory Engineer Itron, Inc. 2401 North State Street PO Box 1735 Waseca, MN 56093 Tel 507-837-5264 Fax 507-837-5200 drew.rosenb...@itron.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Calculating/predicting Quasi-peak of a single pulse
To all, QP detection of the pulse requires a linear detector. The spectrum anlayzer should be set up with uV (rather than dBuV) on the vertical scale. Let me know if the RC time constant displays differently with the new setting (there may be some dynamic range issues so some experimenting may be required). Regards, Kurt Fischer >Date: Mon, 19 Apr 2004 15:29:35 -0600 >From: drcuthb...@micron.com >Subject: RE: Calculating/predicting Quasi-peak of a single pulse >To: , > > >Drew, > >What have you got the RBW and VBW set to? > > Dave Cuthbert > Micron Technology > >-Original Message- >From: owner-emc-p...@majordomo.ieee.org >[mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Rosenberg, Drew >Sent: Monday, April 19, 2004 3:00 PM >To: emc-p...@majordomo.ieee.org >Subject: Calculating/predicting Quasi-peak of a single pulse > > > >Hi EMC Gurus, > I have been struggling with something for a while and have >decided that this is the best place to send my question: > > I would like to better understand how quasi-peak is determined >on a single pulse of specified duration. From my understanding, >Quasi-peak applies an RC time constant to the pulse. If the pulse >length equals 5 times the RC time constant, then the QP measurement will >be roughly 99% of the peak measurement. > According to CISPR-16-1 Table 1, the charging time constant >specified is 1 ms. Therefore, according to my understanding, QP should >be 99% of peak measurement at 5ms. > > However, my experiments have given very different results. I >have an HP8593E spectrum analyzer. In an effort to prove my >understanding of CISPR-16-1's definition of Quasi-peak, I applied a 1 >second 900 MHz pulse to the spectrum analyzer with QP detection on. >This 1 second pulse was applied using the pulse trigger of a Marconi >2024 sig gen. To my surprise, QP did not equal peak until about 500ms. > > Does anyone know why I am getting such different results than >what I had predicted? > > I have data and analyzer pics if anyone thinks that they would >help. I have been told that attachments are not good for list servers, >so please let me know if you would like to see them. > >Regards, > >Drew Rosenberg >Regulatory Engineer >Itron, Inc. >2401 North State Street >PO Box 1735 >Waseca, MN 56093 >Tel 507-837-5264 >Fax 507-837-5200 >drew.rosenb...@itron.com > > > > >--- >This message is from the IEEE EMC Society Product Safety >Technical Committee emc-pstc discussion list. > >Visit our web site at: http://www.ieee-pses.org/ > >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: emc_p...@symbol.com > >For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > >All emc-pstc postings are archived and searchable on the web at: >http://www.ieeecommunities.org/emc-pstc > > >--- >This message is from the IEEE EMC Society Product Safety >Technical Committee emc-pstc discussion list. > >Visit our web site at: http://www.ieee-pses.org/ > >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: emc_p...@symbol.com > >For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > >All emc-pstc postings are archived and searchable on the web at: >http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Calculating/predicting Quasi-peak of a single pulse
Makes me wonder what the Marconi is really doing. A check with a fast oscilloscope will show if the amplitude is rising nicely and is well behaved. Dave Cuthbert From: Rosenberg, Drew [mailto:drew.rosenb...@itron.com] Sent: Monday, April 19, 2004 3:32 PM To: drcuthbert; emc-p...@majordomo.ieee.org Subject: RE: Calculating/predicting Quasi-peak of a single pulse RBW=120kHz VBW=300kHz From: drcuthb...@micron.com [mailto:drcuthb...@micron.com] Sent: Monday, April 19, 2004 4:30 PM To: Rosenberg, Drew; emc-p...@majordomo.ieee.org Subject: RE: Calculating/predicting Quasi-peak of a single pulse Drew, What have you got the RBW and VBW set to? Dave Cuthbert Micron Technology From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Rosenberg, Drew Sent: Monday, April 19, 2004 3:00 PM To: emc-p...@majordomo.ieee.org Subject: Calculating/predicting Quasi-peak of a single pulse Hi EMC Gurus, I have been struggling with something for a while and have decided that this is the best place to send my question: I would like to better understand how quasi-peak is determined on a single pulse of specified duration. From my understanding, Quasi-peak applies an RC time constant to the pulse. If the pulse length equals 5 times the RC time constant, then the QP measurement will be roughly 99% of the peak measurement. According to CISPR-16-1 Table 1, the charging time constant specified is 1 ms. Therefore, according to my understanding, QP should be 99% of peak measurement at 5ms. However, my experiments have given very different results. I have an HP8593E spectrum analyzer. In an effort to prove my understanding of CISPR-16-1's definition of Quasi-peak, I applied a 1 second 900 MHz pulse to the spectrum analyzer with QP detection on. This 1 second pulse was applied using the pulse trigger of a Marconi 2024 sig gen. To my surprise, QP did not equal peak until about 500ms. Does anyone know why I am getting such different results than what I had predicted? I have data and analyzer pics if anyone thinks that they would help. I have been told that attachments are not good for list servers, so please let me know if you would like to see them. Regards, Drew Rosenberg Regulatory Engineer Itron, Inc. 2401 North State Street PO Box 1735 Waseca, MN 56093 Tel 507-837-5264 Fax 507-837-5200 drew.rosenb...@itron.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message was scanned for viruses!! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Calculating/predicting Quasi-peak of a single pulse
RBW=120kHz VBW=300kHz From: drcuthb...@micron.com [mailto:drcuthb...@micron.com] Sent: Monday, April 19, 2004 4:30 PM To: Rosenberg, Drew; emc-p...@majordomo.ieee.org Subject: RE: Calculating/predicting Quasi-peak of a single pulse Drew, What have you got the RBW and VBW set to? Dave Cuthbert Micron Technology From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Rosenberg, Drew Sent: Monday, April 19, 2004 3:00 PM To: emc-p...@majordomo.ieee.org Subject: Calculating/predicting Quasi-peak of a single pulse Hi EMC Gurus, I have been struggling with something for a while and have decided that this is the best place to send my question: I would like to better understand how quasi-peak is determined on a single pulse of specified duration. From my understanding, Quasi-peak applies an RC time constant to the pulse. If the pulse length equals 5 times the RC time constant, then the QP measurement will be roughly 99% of the peak measurement. According to CISPR-16-1 Table 1, the charging time constant specified is 1 ms. Therefore, according to my understanding, QP should be 99% of peak measurement at 5ms. However, my experiments have given very different results. I have an HP8593E spectrum analyzer. In an effort to prove my understanding of CISPR-16-1's definition of Quasi-peak, I applied a 1 second 900 MHz pulse to the spectrum analyzer with QP detection on. This 1 second pulse was applied using the pulse trigger of a Marconi 2024 sig gen. To my surprise, QP did not equal peak until about 500ms. Does anyone know why I am getting such different results than what I had predicted? I have data and analyzer pics if anyone thinks that they would help. I have been told that attachments are not good for list servers, so please let me know if you would like to see them. Regards, Drew Rosenberg Regulatory Engineer Itron, Inc. 2401 North State Street PO Box 1735 Waseca, MN 56093 Tel 507-837-5264 Fax 507-837-5200 drew.rosenb...@itron.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message was scanned for viruses!! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Calculating/predicting Quasi-peak of a single pulse
Drew, What have you got the RBW and VBW set to? Dave Cuthbert Micron Technology From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Rosenberg, Drew Sent: Monday, April 19, 2004 3:00 PM To: emc-p...@majordomo.ieee.org Subject: Calculating/predicting Quasi-peak of a single pulse Hi EMC Gurus, I have been struggling with something for a while and have decided that this is the best place to send my question: I would like to better understand how quasi-peak is determined on a single pulse of specified duration. From my understanding, Quasi-peak applies an RC time constant to the pulse. If the pulse length equals 5 times the RC time constant, then the QP measurement will be roughly 99% of the peak measurement. According to CISPR-16-1 Table 1, the charging time constant specified is 1 ms. Therefore, according to my understanding, QP should be 99% of peak measurement at 5ms. However, my experiments have given very different results. I have an HP8593E spectrum analyzer. In an effort to prove my understanding of CISPR-16-1's definition of Quasi-peak, I applied a 1 second 900 MHz pulse to the spectrum analyzer with QP detection on. This 1 second pulse was applied using the pulse trigger of a Marconi 2024 sig gen. To my surprise, QP did not equal peak until about 500ms. Does anyone know why I am getting such different results than what I had predicted? I have data and analyzer pics if anyone thinks that they would help. I have been told that attachments are not good for list servers, so please let me know if you would like to see them. Regards, Drew Rosenberg Regulatory Engineer Itron, Inc. 2401 North State Street PO Box 1735 Waseca, MN 56093 Tel 507-837-5264 Fax 507-837-5200 drew.rosenb...@itron.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
