# [SI-LIST] Re: Backplane modeling/simulation methodology

• To: <si-list@xxxxxxxxxxxxx>
• Date: Tue, 6 Nov 2007 10:02:19 -0700
However, we found

http://www.altera.com/literature/cp/cp-ftdsimltn.pdf

that with complex and especially 'multi-port' models, simulation becomes
quite inefficient. Just parsing of a large equivalent circuit, depending
on the simulator, may take from 1 to 10 hours. This is unacceptable,
because the pure simulation time is minutes or even seconds.

Though a current crutch-like solution, in a long run producing
equivalent circuits for S-parameters leads to nowhere. Think of the
following: the numerical kernel of any circuit simulator works with
matrices and vectors that are tables of numbers. With vector fitting of
S-parameters, we convert the sampled data into something very similar, a
table of poles and residues. Then, we make something very stupid. We
convert these tables into ***huge*** equivalent circuits, with many
components and internal nodes, that should be parsed and then again
converted by the simulator into matrices, that are much larger than
original and more prone to singularity. On the way, we also introduce
local truncation error, because equivalent circuits contain L/C
components creating differential equation.

>Date: Tue, 6 Nov 2007 10:22:21 +0800
>From: "tao xu" <helen.tao.xu@xxxxxxxxx>
>Subject: [SI-LIST] Re: Backplane modeling/simulation methodology

>Agree with kinger. "Broad Band Spice" can generate Ultra_wide_band
circuits
>for muti-ports S parameter matrix to keep accuracy and solve
convergence
>problem of most cases in Hspice.
>Thanks and regards
>Tao ( Helen )

>On Nov 6, 2007 5:53 AM, Kinger Cai <kinger.cai@xxxxxxxxx> wrote:

> Hi Keyvan,
> As I mentioned you can use the full-wave field solver, HSS or CST, to
> extract the S parameter models (FD).
> If you do not feel comfortable to directly use S parameter in your
Hspice
> simualiton flow, www.Sigrity.com <http://www.sigrity.com/> provides a
> tool, "Broad Band Spice", which
> can convert a S parameter model to broad band spice after doing sanity
and
> passivity check.
> www.Kingercai.com <http://www.kingercai.com/> provides the same
service of
> S paramter models to Bradn
> band Spice converting as well as S parameter modeling.
>
> Regards,
> Kinger
>
> High Speed Platform Enabling
> www.kingercai.com
>

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