Derek, All power supplies are supposed to be tested with a representative system. They are primarily designed to filter the supply emissions, since line filters typically do little filtering above 20 or 25 MHz. Also remember the old saying, "CE plus CE does NOT equal CE"! Bill William M Stumpf DLS Electronics 166 South Carter St. Genoa City WI 53128 ph: 262-279-0210 fx: 262-279-3630 email: bstu...@dlsemc.com
From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Wednesday, July 02, 2003 2:16 PM To: emc-p...@ieee.org Subject: Re: Source of noise Hi All, Thanks for the great replies! looks like the PCI bus is the problem.. But here's the quandry.. Now we are adding the cards back in, they should add little to the profile, correct? After all, they all have the CE mark on them, and some have the FCC sticker too. This is not happening, in fact some emissions are quire strong.. I've also noticed that the Power supply is letting the PC noise out. I opened the power supply ( bang goes the warrenty ), and there is the minimal of filters.. Are the power supplies tested individually to carry the agency sticker?, with a real PC? or just load resistors? Are they designed to suppress the PC noise? Cheers, Derek N. Walton Owner L F Research EMC Design and Test Facility Poplar Grove, Illinois, USA www.lfresearch.com
