In message <201048ea81ba0745aca78e4cc8839001c8b...@desmdswms201.des.grplnk.net>, dated Mon, 19 Feb 2007, "Haynes, Tim (SELEX) (UK Capability Green)" <tim.hay...@selex-sas.com> writes:
>For what it is worth, >IF the resistive device is connected to the active device by screened >cable and the screening keeps active device emissions within the cable, >then the resistive device might act as the antenna and radiate the >active devices emissions.... It's a resistive device, and as far as I know, the cable to the alarm controller normally carries only DC. The matter of re-radiation of common-mode energy from the controller is far more a matter of the controller design than of the pad design. And controller designs vary far more than portable computer designs do. I don't think that the manufacturer of a pad can reasonably predict how an **installation** of the pad and arbitrary choices of controller and other devices and cables might perform. If the pad is marketed as a package with the controller and other devices, then that is a 'system' in the wording of the old EMC Directive, and the system as a whole should be assessed for EMC, tested as necessary, and CE-marked **as a whole**. This doesn't seem to be explained clearly in the guide to the new EMC Directive, which is a pity. > >Like a parallel port printer switch did when the box in which the >switch was housed was made of plastic - after all the switch was >passive! But the signal was high-frequency. The possibility of radiation could be predicted. -- 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 ______________________________________________________________________
