I'm interested too, but I suppose I'll have to wait till "Phase Angles for Dummies" is published.
Ed Price [email protected] WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military & Avionics EMC Is Our Specialty > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of John > Woodgate > Sent: Friday, August 20, 2010 1:40 PM > To: [email protected] > Subject: Re: [PSES] LISN phase characteristic? > > In message > <OFCBD7CEE0.9955CF45-ON88257785.006913CF- > [email protected] > lectric.com>, dated Fri, 20 Aug 2010, > [email protected] writes: > > >I'm trying, but failing to understand why phase would be important for > >a LISN or for any other transducer used during EMC evaluation. Don't > >EMC receivers report received signals as a scalar value? > > I suppose if the impedance is 50 ohms [1] but not resistive, that can > introduce an error or at least affect the 'u-word' (uncertainty). There > is a mathematical rationale in Annex I of CISPR 16-1-2 and maybe some > further explanation in CISPR 16-4-3 and/or CISPR 16-4-4. > > [1] It isn't required to be 50 ohms at all frequencies, and need only > be > within 20% of the required value. The tolerance on the required phase > angle is +/-11.5 degrees. Also, the standard says: > > Where the phase requirement cannot be met, the measured phase angles > may > be taken into account in the uncertainty budget according to CISPR > 16-4-2. Annex I gives guidelines for the calculation of the uncertainty > contribution of the phase if the tolerance is exceeded. > -- > 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]>
