Re: [SI-LIST] : About the AC analysis with HSPICE

Ray Anderson (raymonda@radium.eng.sun.com)
Thu, 2 Sep 1999 10:41:16 -0700 (PDT)

Mike Degerstrom wrote:

>Since your s-parameter meter has 50 ohm ports use ROUT=RIN=50. The .NET
>statement mathematically produces s-parameters. I don't know exactly
>how it works but I've recreated the s-parameter approach using a standard
>small signal AC analysis and get the same results. Beyond this, you
>will need to understand s-parameters to obtain a thorough understanding
>of what you are trying to simulate.

A number of years ago Ravinder Goyal (then at Mentor Graphics)
published an article in one of the trade mags (don't remember which one
at the moment) where he described a method for creating s-parameter
measurements in spice by using a "software network analyzer" composed
of a couple of dependent current or voltage sources and a few resistors.
I don't remember the exact details at the moment. Anyway, the example
circuit he showed in the article to demonstrate his method (a 5 pole
LC bandpass filter) showed up in the Hspice 96 manual as an example
of how to use the Hspice .NET statement.

I've always wondered if Ravinder's methodology was "under the
hood" of the .NET statement.

I think I've got a spice deck around here somewhere that
implements the method described in the article. If I can find it
I'll post it to the list. As I remember, it got almost the identical
results the .NET statement did.

-Ray

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