A relatively simple resistive network can be designed for measuring common-mode voltage on Ethernet and many other high-speed interfaces that utilize differential-pair lines, which - with minor modifications - would be perfectly suitable for this application. I have used it for about 10 years, had a paper about it at the Seattle IEEE EMC Symposium (about 8 years ago - coincidently about as long as the standard has been chewed on). Meanwhile it has evolved into a more versatile device than what was described then. But I gues it may be of no interest to people who write standards <grin> Neven
-------------- Original message -------------- From: John Woodgate <j...@jmwa.demon.co.uk> > In message > , > dated Thu, 13 Apr 2006, jim.hulb...@pb.com writes > >We have an ethernet port to which is connected a CAT5 cable. When this > >cable is routed through an ISN per EN 55022 for conducted emissions > >measurements, the port is unable to function. What experience have > >people had with ISNs in this application, or what experience do people > >have with the alternate test methods (current probe and/or voltage > >probe measurements)? > > Since it's taken about 8 years to get even a fragile agreement on > conducted emissions in CISPR 22/EN 55022, you'd think that everything > would be crystal-clear by ! now. > > I don't know which edition of EN 55022 you are using by the 1998 > edition, with corrigenda 1 and 2 and amendments 1 and 2 says in 9.5.3.1: > 'Where normal functioning cannot be achieved because of the impact of > the ISN on the EUT, the measurement shall be carried out using the > method given in 9.5.3.5.' This in turn refers you to Annex C, C.1.3 or > C.1.4. > > C.1.3 uses a current probe and a voltage probe. C.1.4 uses two current > probes and a moveable ferrite 'adjuster'. It takes a long time. > -- > OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk > 2006 is YMMVI- Your mileage may vary immensely. > > John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pst! c discu ssion list. Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to emc-p...@ieee.org > > 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 emcp...@ptcnh.net > Mike Cantwell mcantw...@ieee.org > > For policy questions, send mail to: > > Jim Bacher: j.bac...@ieee.org > David Heald: emc-p...@daveheald.com > > 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. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org 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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
