Re: Related Question [Re: your question about digital variable access]


Subject: Re: Related Question [Re: your question about digital variable access]
From: Kevin Cameron x3251 (Kevin.Cameron@nsc.com)
Date: Mon Mar 19 2001 - 10:33:23 PST


Martin Wrote: >>>>>>
> Based on this, which method should be used to determine the value of
> analog variables accessed in the digital context?

Graham,
I think that interpolation makes most sense for analog signals.
After all the analog kernel is trying to simulate continuous signals.
References to voltages e.g. V(a) and analog real variables should be
interpolated. However interpolating analog integers is a bad idea so
I suggest that that the previous time point value be used for those,

--Martin

>Is there an alternative that I have not considered yet?
<<<<<<<<<<<<<

Linear interpolation for nodes and "last-value" for other data is what
I specified as part of the scheduling semantics proposal -

 http://www.eda.org/verilog-ams/htmlpages/tc-docs/issues/misc/schd_sm.pdf

The alternative would be polynomial interpolation, but since Analogy's
"Calaveras" patent uses both roll-back and polynomial interpolation I'm
avoiding them.

If anyone wants to do polynomial interpolation, I would suggest adding
attributes to disciplines at a later date.

Kev.

-- 
National Semiconductor
2900 Semiconductor Drive, Mail Stop D3-677, Santa Clara, CA 95052-8090



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