You're singing to the choir now! I was ecstatic when fiber came up. Pictured
me sitting around have a fine time. Then reality hit. As noted below by
Michael a share of the problem does belong to the transceivers and cables.
Good signal integrity work up to the transceiver is a must. But the location
of the drive circuitry so near a large, when compared to the operating
frequencies, opening allows some of the signal to escape the box and
re-radiate from cable connector housings and ferules. Heavy sigh.
A quick glance at the e-mail address should convince you that it is a wide
problem, not just an inadequate design from a single source.
Gary
-----Original Message-----
From: [email protected] [SMTP:[email protected]]
Sent: Wednesday, June 16, 1999 11:56 AM
To: EMC-PSTC
Subject: Fw: RE: EMC Issues with Fiber Optics
Posted for Erwin Gomez:
------------------------
From: "GOMEZ,ERVIN (HP-SantaClara,ex3)"
<[email protected]>
Subject: RE: EMC Issues with Fiber Optics
Date: Tue, 15 Jun 1999 18:05:34 -0600
To: "'[email protected]'" <[email protected]>,
[email protected]
Cc: [email protected], [email protected]
>
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]
> Sent: Tuesday, June 15, 1999 2:56 PM
> To: [email protected]
> Cc: [email protected]; [email protected]
> Subject: Re: EMC Issues with Fiber Optics
>
>
>
> Jim,
>
> It is true. Systems with fiber optic links have radiation
problems
> associated with the fiber optic signaling system. It is still
true
> the optical fiber does not radiate! <grin> Its just the non-fiber
> stuff used to generate the optical signal which does.
>
> The usual techniques for shielding etc. when properly done can do
a
> satisfactory job with the energy emanating from on-board
components
> and operations. The real bugaboo comes when the optical device is
the
> problem and the opening in the chassis is large (i.e. SC size) to
> accommodate interconnection. There are times when the device can
be so
> bad that even cutting the aperture size in half doesn't help much.
In
> addition, the construction and materials in the external optical
fiber
> connector can be significant contributors to the problem as well.
> I've seen all these situations.
>
> Hope that helps...
>
> -Michael
>
> >
> >
> > To All,
> >
> > I am wondering if anyone has experience with EMI problems, or
issues,
> with
> > digital (computer) systems that employ fiber optic links.
> >
> > While the outside world seems to think that fiber optics
eliminate EMI
> from
> > the design equation, I have heard that real fiber optic systems
can
> exhibit
> > real EMI problems. These problems (at least as far as emissions
are
> > concerned) often are aperture radiation, either from apertures
in
> proximity
> > of the fiber optic cards, or from the fiber aperture, itself.
> >
> > Does anyone have experience to share?
> >
> > Eagerly,
> >
> > Jim
> >
> > Dr. Jim Knighten e-mail:
[email protected]
> > Senior Consulting Engineer
> > NCR
> > 17095 Via del Campo
> > San Diego, CA 92127 http://www.ncr.com
<http://www.ncr.com>
> > Tel: 619-485-2537
> > Fax: 619-485-3788
> >
--------------------------
Ed Price
[email protected]
Electromagnetic Compatibility Lab
Cubic Defense Systems
San Diego, CA. USA
619-505-2780
Date: 06/16/1999
Time: 10:55:41
Military & Avionics EMC Services Our Specialty
Also Environmental / Metrology / Reliability
--------------------------
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