Kevin,
Logically speaking, if the standard requires you to meet a 1 Hz pulse frequency, it does not seem reasonable to fail you on the first or last cycle if they are faster than 1 Hz. As you mention, triggering the modulation (or carrier) on the other would remove this uncertainty. Another possible way of distinguishing the cause of the failure is to leave the RF carrier and modulation on, reset the equipment and see if a failure still occurs. It may be necessary to step down the amplitude and then raise it back to the required level. It was my understanding that the test is typically conducted with the RF carrier on first and then the modulation switched on. It is reasonable to assume that if an un-modulated carrier causes interference, then a modulated carrier would definitely cause interference. I have seen equipment behave poorly to an RF carrier being switched on, but behave normally when the RF carrier is moved between step frequencies. To answer your last two question more specifically: If you fail the requirement. Non-synchronized, if it does make a difference, will yield a higher level of compliance. I do not remember if IEC 61000-4-6 requires synchronized start between modulation and carrier. Michael Peters _____ From: [email protected] [mailto:[email protected]] On Behalf Of Kevin Harris Sent: Thursday, February 09, 2006 12:00 PM 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. 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