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Simulators >> RF Simulators >> How small is 'small signal' in Spectre PAC, PXF and PNoise?
https://designers-guide.org/forum/YaBB.pl?num=1312304416

Message started by ppg on Aug 2^nd, 2011, 10:00am

Title: How small is 'small signal' in Spectre PAC, PXF and PNoise?
Post by ppg on Aug 2^nd, 2011, 10:00am

Dear All,

How shall one define the domain of validity of Spectre PAC, PXF and PNoise for oscillators knowing that for oscillators "even small-input perturbations lead to, over time, large changes in phase and timing properties" (see IEEE CAD Vol26 June 2007 p1054 by T. Mei)?

For small input signals larger than small in the sense of PAC, PXF and PNoise what are analysis alternatives? Spectre QPAC, QPXF and QPNoise?

Thank you,
Best Regards,
ppg

Title: Re: How small is 'small signal' in Spectre PAC, PXF and PNoise?
Post by Ken Kundert on Aug 2^nd, 2011, 12:30pm

Small signals do not create distortion.

-Ken

Title: Re: How small is 'small signal' in Spectre PAC, PXF and PNoise?
Post by ppg on Aug 2^nd, 2011, 1:59pm

Hi Ken,

Yes, I agree.
Now what will be the best way to check for distortion using Spectre RF? Via the PAC specialized analyses ... like 'Compression Distortion Summary' or ... ? Please provide pointer to possible tutorial info on such type of Specialized Analyses. Thank you.

Does distortion includes situation where the small signal could alter the oscillation frequency and result in large accumulated non periodic variations? Are such effects included in PAC Specialized Analysis?

Best Regards,
ppg.

Title: Re: How small is 'small signal' in Spectre PAC, PXF and PNoise?
Post by Ken Kundert on Aug 2^nd, 2011, 3:12pm

I'm afraid I have no personal experience with the PAC specialized analyses. However, if it were me I would try the distortion summary if I were interested in knowing the distortion of my circuit when it is operating well out of compression. They should be faster and more informative than the QP analyses.

-Ken