RE: [SI-LIST] : FCAL DB9 cable shield

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From: Jeremy Stover (
Date: Mon Jan 10 2000 - 11:27:34 PST

Can someone point me to the info for signing up on the emc-pstc list
referenced below?


Jeremy Stover
LSI Logic
3718 N. Rock Road
Wichita KS 67226

                -----Original Message-----
                From: Knighten, Jim L
                Sent: Thursday, November 18, 1999 10:58 AM
                To: si-list@silab.eng.Sun.COM
                Subject: RE: [SI-LIST] : FCAL DB9 cable shield


                Ah! This is the fun part of EMI.

                You correctly characterize my underlying assumption , i.e.,
the noise source is imbalance in the differential signal within the
Over the past couple of years, some have termed this "signal-induced"
rather than the EMI source that is external to the cable and merely
a ride" on the cable shield. I can point you to at least 2 papers in
August 1999 IEEE EMC Symposium and one in 1998.

                In my experience at NCR, with the FC applications that we
have, this has always been the dominant problem. I must say that we
a lot of energy designing our boards to be quiet.

                Of course there is one solution that eliminates the ground
loop noise problem (Ron's opinion). That is the use of fiber optics
instead of copper cables. Be warned, however, that this does NOT
the EMI problem.It merely changes its nature. I have stated in another
thread that a myth of modern technology is that fiber optics are
EMI-proof. If
you log onto the emc-pstc list server, you will find that modern high
data rate fiber optics present huge EMI challenges because the
used are so noisy and connectors are so poorly designed for EMI

                Dr. Jim Knighten e-mail:
                Senior Consulting Engineer
                17095 Via del Campo
                San Diego, CA 92127
                Tel: 858-485-2537
                Fax: 858-485-3788

                ***** Notice the Area Code change from 619 *****

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