[SI-LIST] Re: EMI simulation tools at PCB level
- From: Julian Ferry <julian.ferry@xxxxxxxxxx>
- To: 'Chris Cheng' <Chris.Cheng@xxxxxxxxxxxx>, "'si-list@xxxxxxxxxxxxx '" <si-list@xxxxxxxxxxxxx>
- Date: Mon, 6 Dec 2004 15:46:52 -0500
Chris,
To be clear here, I'm not a software salesman. Maybe someone who earns their
money selling this stuff can jump in and answer your question in a more
positive way. I don't want to sell something short.
Your first scenarios would be doable for sure. Been there, done that. But I
think the problems you talk about below are getting too complicated. Some
design of experiment type work would be required to constrain things to make
it practical. Otherwise, based on my experience, you would be wasting your
time.
That's one reason I recommended working with a consultant on something like
this, at least until you gain some experience. A good, honest one (yes, they
really do exist) would tell you that your expectations are unrealistic, and
hopefully offer you an alternative approach that makes more sense.
Julian Ferry
High Speed Engineering Manager
Samtec, Inc.
-----Original Message-----
From: Chris Cheng [mailto:Chris.Cheng@xxxxxxxxxxxx]
Sent: Monday, December 06, 2004 1:24 PM
To: Julian Ferry; Chris Cheng; ''rmatthews@xxxxxxxxxx' ';
'rsefton@xxxxxxxxxxxxx '; 'si-list@xxxxxxxxxxxxx '
Subject: RE: [SI-LIST] Re: EMI simulation tools at PCB level
Julian,
If you think the complexity of analyzing individual component/assembly will
take you 24x7x52. How would you think if a few hundred of them (similar or
different parts) are randomly put together within an enclosure that has
arbitrary openings everywhere ? And to put things in better perspective, if
I tighten my screws by one turn, that's a change of dimension by a fraction
of a mm in a couple meter size enclosure. Do you think your tools can
predict what will happen ?
-----Original Message-----
From: Julian Ferry
To: 'Chris Cheng'; 'rmatthews@xxxxxxxxxx'; rsefton@xxxxxxxxxxxxx;
si-list@xxxxxxxxxxxxx
Sent: 12/6/2004 8:36 AM
Subject: RE: [SI-LIST] Re: EMI simulation tools at PCB level
Chris,
Samtec doesn't design any servers or computers. We wouldn't want to step
on
our customers toes, now would we?
But we do design connectors, pcb's, cable assemblies, and other
components
that go into some bleeding edge systems. And the components that we
design
can have a major impact on those systems' EMI performance. So we need to
know what's going on.
Well, I guess we don't really _need_ to know what's going on. We could
leave
those headaches for you systems design guys to figure out. But we like
to
help out as much as we can....
You said: "I've always wanted to simulate why if I tighten the screw by
one
more turn on my door and my EMI gaskets compressed a little harder and
the
signature changed by 10 db. Or if I hang the cable this way or that way
the
signature changed by a few db."
My point is that software is available to simulate these kinds of
problems.
Accurately too. These are the kind of relative comparisons I was talking
about. We do them all the time.
I think most engineers who have been around this stuff long enough
realize
that the signaling environment used in these simulations is not going to
be
the same as what will be seen in any particular system. That's the
missing
link in the "Holy Grail" sort of software that Kai, Scott and others
alluded to.
And I agree with Scott to some extent. That is something that we
probably
won't see in his lifetime. It might happen in my lifetime though,
because
I'm a lot younger than he is...
Julian Ferry
High Speed Engineering Manager
Samtec, Inc.
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