CISPR standards mostly require a search for worst-case, but give examples of acceptable placement. With best wishes DESIGN IT IN! OOO - Own Opinions Only <http://www.jmwa.demon.co.uk/> www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England Beware averages! They hide or discard data, and may distort it (them?). From: Cortland Richmond [mailto:k...@earthlink.net] Sent: Saturday, September 2, 2017 10:53 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] God EMC practice In ancient times, the FCC required we perform RE testsby manipulating peripheral and cable placement to maximize emissions; our tech at Tandy was fiendishly clever, but we had to draw the line short of wrapping cables around the (CRT) monitor.
Lots of stories... Cortland Richmond On 9/1/2017 8:10 PM, Brent DeWitt wrote: I agree with Jim that your calculated measurement uncertainty is the minimum margin that one should apply. This could be doubled by assuming the second assessing laboratory had the same uncertainty, but in the opposite direction! In practice, I believe that the products cabling, and therefore the setup uncertainty, may become dominant. When I perform radiated emissions measurements on a product with multiple cables, I observe a wide span of potentially "interesting" emissions on the SA/receiver, then grab the entire bundle of cables and simply toss them randomly. If things wiggle by a couple of dB, I move on. If things swing by ten dB, I've got my work cut out for me to maximize and I advise the customer to take a much more generous approach to their margin requirements. Brent G DeWitt Milford, MA - ---------------------------------------------------------------- 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 <mailto:emc-p...@ieee.org> > All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org <mailto:sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org <mailto:mcantw...@ieee.org> > For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org <mailto:j.bac...@ieee.org> > David Heald <dhe...@gmail.com <mailto: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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
