My point exactly. In particular, rfi limits have to be based on some quality of reception that is achieved at some signal-to-noise ratio. If you live in an area with a strong radio signal, a device can emit way more EMI than the limits allow and not cause rfi. If you live far from the broadcaster, something emitting right at the limit may cause objectionable interference.
The placement of the limits was deliberate, as Mr. Woodgate states. But the effect of the limits is all over the place. There is simply no way to improve on Mr. Woodgate's closing comment, so I'm not even going to try. Ken Javor Phone: (256) 650-5261 > From: John Woodgate <j...@jmwa.demon.co.uk> > Date: Wed, 11 Aug 2010 18:31:43 +0100 > To: <emc-p...@ieee.org> > Subject: Re: Calibration supplier for signal generator with pulse modulation > > In message <c88840fe.84571%ken.ja...@emccompliance.com>, dated Wed, 11 > Aug 2010, Ken Javor <ken.ja...@emccompliance.com> writes: > >> EMI limits are quite arbitrary; > > Well, not quite. They are set, or re-set, so as to keep complaints of > EMI to an acceptable minimum. But the uncertainty in that process is > huge. So the whole edifice rests on feet of clay. > -- > 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 > <emc-p...@ieee.org> > > 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 <emcp...@socal.rr.com> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher: <j.bac...@ieee.org> > David Heald: <dhe...@gmail.com> - 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 <emc-p...@ieee.org> 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 <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
