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Simulators >> Circuit Simulators >> ADSL linearity sims in spectre: psf vs. sst2 data
https://designers-guide.org/forum/YaBB.pl?num=1197934686

Message started by David Sobel on Dec 17^th, 2007, 3:38pm

Title: ADSL linearity sims in spectre: psf vs. sst2 data
Post by David Sobel on Dec 17^th, 2007, 3:38pm

Hello,

Hopefully Andrew Beckett will see this post and add shed some light on this issue... :)

I'm trying to simulate some ADSL circuits (i.e. >90dB linearity specs) , and I've found that I get VERY different results for when I have the output file in psf format vs. sst2 format. In short, the psf output looks good (~95dB linearity), but the exact same sim in sst2 format is garbage, with only ~40dB linearity.

I'm running a transient sim in conservative mode with default tolerances. I've also specified a strobeperiod so that the dft function has "real" data at the sampling points.

Any explanation as to why sst2 output gives lousy results? Is there any way to make sst2 output better? If not, is there a way to force output to psf?

Thanks much!
David

Title: Re: ADSL linearity sims in spectre: psf vs. sst2 d
Post by Frank Wiedmann on Dec 17^th, 2007, 11:46pm

This looks like a known bug in MMSIM, see http://sourcelink.cadence.com/docs/db/kdb/2006/May/11244704.html. The bug was fixed a year and a half ago, so upgrading to a recent version of MMSIM should solve the problem. You can also solve the problem by changing the output format to psf, see http://sourcelink.cadence.com/docs/db/kdb/2006/Jan/11220962.html for instructions.