That answered 90% of my unknowns. One last degree of freedom appears yet to be uncontrolled. That is XMTR - RCVR separation. That would also have to be fixed in order to get repeatable results. Is that the case?
---------- >From: Kevin Harris <harr...@dscltd.com> >To: "'Ken Javor'" <ken.ja...@emccompliance.com>, "EMC-PSTC (E-mail)" <emc-p...@ieee.org> >Subject: RE: RF testing question >Date: Tue, May 8, 2001, 6:39 AM > > Hi Ken, > > Let me try to explain it better. The standard asks that you stop reducing > the signal strength one you cross the 25% threshold. I would imagine that it > would be very hard to get exactly 25% So for example if you got a 10 % > failure rate at one level then reduced the transmit signal strength by 1 dB > and got a 30% failure rate you would stop there. Also many digital systems > would likely have an all or nothing response so getting a 25% failure rate > would be not possible. > As to "restoring to full power" the power level of the transmitter in this > case is fixed, the signal strength of the system is reduced by adding > attenuation in line to the transmitter antenna. This is simply removed once > the threshold is determined and the interference signal is added to the > equation. > > Regards > > Kevin > > > -----Original Message----- > From: Ken Javor [mailto:ken.ja...@emccompliance.com] > Sent: Monday, May 07, 2001 10:48 PM > To: Price, Ed; 'Kevin Harris'; EMC-PSTC (E-mail) > Subject: Re: RF testing question > > Either I am being dense, or there is not enough info in the > problem > statement. Mr. Harris states that after determination of > the interference > level (that signal which yields no better than 25% error > rate plus 40 dB) > the transmitter is returned to full power. How is full > power defined? The > success or failure of this test will depend on that. Also, > the words 25% OR > MORE of the signals are not understood (my emphasis) are > unclear. If I > wanted to pass this test, I would reduce the transmitter > level until no > signals are understood, then add 40 dB to that number and I > would get a > lower susceptibility signal than if I had stopped at > precisely the 25% > level. So to me it seems that there are two uncontrolled > variables here: > the baseline for establishing the susceptibility signal > level, and the level > at which the desired signal is transmitted. What am I > missing (besides > maybe some of my dear, departed brain cells)? > > > ------------------------------------------- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net 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.rcic.com/ click on "Virtual Conference Hall,"
