Re: [SI-LIST] : IBIS Subcommittee Formed to Review Spice to IBIS

jonp@pacbell.net
Tue, 08 Jun 1999 09:26:20 -0700

I agree with Weston.

Either that or remove the quite artificial limit of number of points in an IBIS
file.
I have actually been faced with the problem that even with software to remove
extra points I cannot
create IBIS models to the accuracy that I desire with the 100 point limitation.

jon powell
Viewlogic Consulting Services

Beal, Weston wrote:

> Kellee,
>
> You're disagreeing a mute point. Your point was the same point I was trying
> to state by saying, "the IBIS creator tool should have an algorithm to
> remove points in linear regions." We should delete all these extra data
> points. The problem that s2ibis has now is that all points are equal
> difference. They should be closer in knee points and very sparse is linear
> regions. The IBIS creator tool should have an algorithm to clean out extra
> data.
>
> So, I agree with you and now you can agree with me.
>
> Later,
> Weston Beal
> Signal Integrity Engineer
> Compaq Computer Corp.
>
> -----Original Message-----
> From: Kellee Crisafulli [mailto:kellee@hyperlynx.com]
> Sent: Monday, 07 June, 1999 2:19 PM
> To: Beal, Weston; ibis@eda.org
> Subject: RE: [SI-LIST] : IBIS Subcommittee Formed to
> Review Spice to IBIS
>
> Hi
>
> I have a comment on Weston's comment on the number of data
> points.
> I disagree on one point. Instead of increasing the number
> of points generated
> in the IBIS file the spice to IBIS tool should improve the
> quality of the
> points
> choosen.
>
> I can hand build files with 50 points that out perform files
> with 400 points.
> The big gain is that the FILE SIZE is reduced with higher
> accuracy.
> Large IBIS files will take up many megabytes on 1000's of
> hard drives.
> The V/I and V/T tables are the largest part of IBIS files.
> Increasing them 4 x will generally increase the file size 3
> x or more.
>
> >The third thing that I changed was the number of points in
> the time
> >waveforms from 50 to 101. I have to remove one point to
> comply with the
> >golden parser, but I get better detail. On the issue of
> number of points in
> >a curve or waveform, I think the user should be able to
> define any degree of
> >granularity and the IBIS creator tool should have an
> algorithm to remove
> >points in linear regions. If the resulting curve still has
> too many points,
> >then increase the linearity tolerance and try it again.
>
> Best wishes...
> Kellee