In message <001401c6b62f$97e938c0$6401a8c0@homepc>, dated Wed, 2 Aug 2006, Iain Summers <[email protected]> writes
>What I'd like to know is how large the measurement errors are. eg I >have used a loop (which is the recognised method) and then converted to >E for comparison to others results by using E/H=377 which is only true >in the far field. I though it would be useful to determine what the >results might be if E/H approached 3000 or 30 You can get a rough idea of what the magnitude of E/H does by considering the type of sending antenna. If it's a wire of length comparable with lambda/10 or more, then E/H -> very large at short ranges. If it's a loop, then H/E -> very large at short ranges. I expect you know this, but it is relevant to the answer to your question. [snip] > >The overall aim of my PhD is not to come up with any answers per se but >to explain to others who quote EMC theory in relation to PLT >measurement. There are lots of assumptions but no one aver states "the >answer is x and by the way that is + or - 50%". There are lots of >people measuring E in dBuV to 2 decimal places with no mention of the >errors in their measurements. This is fine for compliance if everyone >does the same thing but some people are trying to predict interference >based upon these results. This is a different subject. My approach to uncertainty in EMC measurements is to say that the value is 'very', for quite large values of 'very'. You may find CISPR 16-3 and some of the sections of CISPR 16-4 slightly helpful. http://www.iec.ch/searchpub/cur_fut.htm -- 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-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
