That's interesting. The change from 50 to 60 Hz would change some input components and that could effect the input impedance and hence the conducted emissions signature but the voltage, especially if its a well regulated and filtered supply should be invisible. The components that radiate at that point are all of the secondary 5 or 3.3 volt oscillators and stuff. They shouldn't even know the difference in the input voltage. If using a switcher power supply it seems even more odd. The input voltage is rectified and then chopped to "#$@ then more regulating and filtering stuff happens. Then it hits the electronics. Anybody else see this and have an idea why it might. I may be living in a fools paradise here. Gary McInturff Packet Engines
-----Original Message----- From: hmellb...@aol.com [SMTP:hmellb...@aol.com] Sent: Monday, July 06, 1998 11:16 AM To: dwight.hunnic...@vina-tech.com; emc-p...@ieee.org Cc: eric.lif...@natinst.com Subject: Re: Ce versus FCC I have encountered certain European agencies requesting that not only are the conducted emissions required to be performed at 230V 50Hz but radiated emissions as well. I agree that for conducted emissions it may make a difference but I have not seen radiated emissions change when the power source is changed from 60 to 50 Hz (while keeping Voltage the same). I did, however, see recently a product change emissions when the voltage was changed from 120 to 230 V. And, it did not matter if it was 50 or 60 Hz, only the voltage was significant. Go figure! Hans