Re: Source of noise

2003-07-03 Thread lfresea...@aol.com
In a message dated 7/2/2003 11:23:03 PM Central Daylight Time, j...@jmwa.demon.co.uk writes: Where did you get the idea that 'CE stops at 30 MHz'? The test for *conducted emissions on the mains lead* goes up to 30 MHz. Emissions at higher frequencies are controlled by the requirements for radiat

Re: Source of noise

2003-07-03 Thread John Woodgate
I read in !emc-pstc that lfresea...@aol.com wrote (in <136.21721a07.2c34 9...@aol.com>) about 'Source of noise' on Wed, 2 Jul 2003: >In messing around, at about 40 MHz, the PC noise is showing up on >the power cord. I guess noone worries because CE stops at 30 MH

Re: Source of noise

2003-07-02 Thread lfresea...@aol.com
In a message dated 7/2/2003 3:03:29 PM Central Daylight Time, bstu...@dlsemc.com writes: 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

RE: Source of noise

2003-07-02 Thread Bill Stumpf
m 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

Re: Source of noise

2003-07-02 Thread robert Macy
Derek, Most of the PS manufacturers I've dealt with use passive dummy loads or "quiet" active loads. These very handy quiet active loads provide programmable loading, BUT IN NO WAY SIMULATE THE SUPPLY'S ACTUAL USE. In other words, how many quiet loads do you power? Almost every load is a micro

Re: Source of noise

2003-07-02 Thread lfresea...@aol.com
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

RE: Source of noise

2003-07-02 Thread Knighten, Jim L
://www.ncr.com 17095 Via del Campo San Diego, CA 92127 tel: 858-485-2537 fax: 858-485-3788 From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Wednesday, July 02, 2003 9:39 AM To: emc-p...@ieee.org Subject: Source of noise Morning folks.. I find myself wrestling with PC emissions again

RE: Source of noise

2003-07-02 Thread rlinf...@sonicwall.com
control the firmware is very helpful. Hope this helps and good luck. RICK LINFORD rlinf...@sonicwall.com From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Wednesday, July 02, 2003 10:39 AM To: emc-p...@ieee.org Subject: Source of noise Morning folks.. I find myself

Source of noise

2003-07-02 Thread lfresea...@aol.com
Morning folks.. I find myself wrestling with PC emissions again. No names this time :-) Above 500 MHz, I'm seeing a bunch of reasonably stable harmonics with about a 33 MHz spacing. Any thoughts as to what they may be from? I've played with all the case openings etc, and also added a ferrite be