In message <09c2d42ff0bfca4b829cdbe89b8f66ffe87...@g3w0637.americas.hpqcorp.net>, dated Thu, 28 Jun 2007, "Conway, Patrick R (Houston)" <p.con...@hp.com> writes:
>A) Margin at certification time has no intrinsic value. > A certificate granted with 0.5 dB margin is just as valid >as one with 10.5 dB of margin. Not quite. It depends on whether the manufacturer can measure the product but uses a test-house to get a third-party certificate, or relies wholly on a test house. In the former case, a margin of 6 dB or so should ensure that the test-house will pass the product at the first try, even if it's by only 0.5 dB. In the second case, the manufacturer really has no opportunity to establish a margin. The designers are working in the dark, and EMC has to be imposed after design, which is very inefficient and costly. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk There are benefits from being irrational - just ask the square root of 2. 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 emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com 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 ______________________________________________________________________
