I may be completely missing the point of the post here, but pulse modulation is a switch. The rf is on all the time, but the PM acts as a switch that gates the output. So when the switch turns on, you get rf out for however long the pulse is high. Then when it goes low, there is no rf out. Seems to me that mathematically speaking the signal generator output is the convolution of the pulse modulation waveform and a constant function, which means that "AND"ing these two together yields an rf output that precisely follows the gating waveform.
From: Kevin Harris <[email protected]> List-Post: [email protected] Date: Thu, 9 Feb 2006 11:59:43 -0500 To: [email protected] Subject: Conducted Immunity Question Hello Group, I recently been discussing conducted immunity testing with some colleagues and we have discovered that we have differing opinions on the intent of the standard. In particular we are referring to the EN 61000-4-6 in pulse mode testing. Our product family standard EN50130-4 calls out this base standard with a 1HZ 50% duty cycle pulse rate. The discussion centers around synchronization of the modulation source (1 Hz) and the RF. The standard does not specify explicitly that these signals should be synchronized but one of us feels that it must be so by implication. If one assumes no synchronization ( i.e.. The modulation signal is free running and at some point the RF is enabled ) then the first and last pulses of the train can be of any length (up to 1/2 period) and not the 1Hz 50% pulse called for. The concern here is this would add some unknown uncertainty to the test as well as reproducibility issues. The counter argument to that is, the on off time is really irrelevant, and that any issue arising from uncertain pulse length, should be classed as a failure, as that perhaps is more "real world". What do you feel? Is synchronization important here? Is a non synchronized test system compliant with the standard? Thanks Kind Regards, Kevin Harris Manager, Approvals Group Digital Security Controls 3301 Langstaff Road Concord, Ontario CANADA L4K 4L2 Tel: +1 905 760 3000 Ext. 2378 Fax +1 905 760 3020 Email: [email protected] This transmission is intended to be delivered only to the named addressee(s) and may contain information that is confidential or proprietary. If this information is received by anyone other than the named addressee(s), the recipient(s) should immediately notify the sender by e-mail or by telephone at 905-760-3000 and delete this message. In no event shall this material be read, used, copied, reproduced, stored or retained by anyone other than the named addressee(s), except with the express written consent of the sender. Thank you. - ---------------------------------------------------------------- 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 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
