It seems to me Gert may only be aware of harmonic distortion.
Distortion can be of various kinds, see e.g. http://en.wikipedia.org/wiki/Distortion. Not that I blindly trust all that is on Wikipedia, but this was quick and convenient, and seems "good enough". If you pass signal through an element that has a response which is non-linear with frequency, e.g. an inductor, you get a frequency-response distortion. There is a very good reason why ethernet transceiver (PHY) manufacturers specify NOT to use a 2-wire CM chokes on the PHY side of the transformer if the PHY is a current drive. They also recommend using 3-wire CM chokes in these condtions. It seems to me that Gert think to know somehtig that makes these recommendations wrong. WIth my limited experience, I have seen the effects of it, which was a no-link situation. This is getting off topic and has not much to do with the OP. ----- Original Message ----- From: "qualified testing bv - Gert Gremmen ce-test" <[email protected]> To: "John Woodgate" <[email protected]>, [email protected] Sent: Tuesday, October 5, 2010 10:27:52 AM Subject: RE: [PSES] EMI issue with Ethernet That is true, but then, on an internet forum it is very important to use the right words to address something. It is difficult enough to explain complex circuits without images (Scott, Mike, Jim, David !!) without babylonic misunderstandings. Gert -----Oorspronkelijk bericht----- Van: [email protected] [mailto:[email protected]] Namens John Woodgate Verzonden: dinsdag 5 oktober 2010 14:17 Aan: [email protected] Onderwerp: Re: [PSES] EMI issue with Ethernet In message <[email protected]>, dated Tue, 5 Oct 2010, "ce-test, qualified testing bv - Gert Gremmen" <[email protected]> writes: >Impedance cannot create distortion. You need a non-linear element for >distortion to happen. There is no non-linear element Without taking sides in this specific debate, it depends on what you mean by 'distortion'. A reactance can introduce phase shift, which certainly 'distorts' pulse shapes, but does not create harmonics of intermodulation. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
