Picking a very small nit, field intensity is measured in terms of Volts per meter, these days. Radiated power density is measured in terms of Watts per square meter.
The reason that Stoddart so named their devices, which clearly are two-terminal voltmeters, and not in and of themselves field intensity meters, is that back in the day field intensity was measured as an rf potential. That is, the limit on radiated field intensity was given as an rf potential at the terminals of a specific antenna located a specific distance and orientation relative to the test sample. This was clear recognition of a fundamental fact often overlooked today. When measuring the near field (it was 12" from the test sample back then), "field intensity" has little meaning and what is of interest is what couples to an antenna or pick-up device that looks like the victim of interest, placed at a representative distance from the test sample. The best thing about this technique (termed an "antenna-induced" limit and test method) was that it avoided this pernicious comparison of radiated emissions and radiated susceptibility/immunity requirements. This comparison is wrong as I will explain in response to Ed Price's posts on this subject. Ken Javor Phone: (256) 650-5261 > From: John Woodgate <[email protected]> > Date: Mon, 1 Dec 2008 15:29:48 +0000 > To: <[email protected]> > Subject: Re: EMI Receiver > > In message > <baaffc88eeb3c541b27f567064251ef905333...@desmdswms202.des.grplnk.net>, > dated Mon, 1 Dec 2008, "Price, Andrew (SELEX GALILEO, UK)" > <[email protected]> writes: > > >> What was wrong with the old Stoddart/Ailtech Identity? >> >> "EMI/Field Intensity Meter" > > But does it measure field intensity, in watts per square metre? > -- > OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk > Either we are causing global warming, in which case we may be able to stop it, > or natural variation is causing it, and we probably can't stop it. You choose! > John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK > > - > ---------------------------------------------------------------- > 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]>
