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Simulators >> Circuit Simulators >> reduced noise with more sidebands in PNOISE analys
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Message started by vivkr on Jan 14^th, 2008, 4:51am

Title: reduced noise with more sidebands in PNOISE analys
Post by vivkr on Jan 14^th, 2008, 4:51am

Hi,

I get inexplicable results when using PNOISE analysis. I was just playing with the circuit (a switched-cap amplifier),
and I raised the number of sidebands from Nsb=200 to Nsb=1000, while scaling up the maxacfreq parameter in PSS analysis by
a corresponding amount.

I get more noise when using 200 bands than what I get with 1000. I do not see any error or warning messages in the log and the
circuit is unchanged. How is this possible? Any comments?

Thanks
Vivek

Title: Re: reduced noise with more sidebands in PNOISE an
Post by David Lee on Jan 14^th, 2008, 1:31pm

This happens on highly nonlinear circuits containing sharp waveforms and narrow pulses.
Does this describe your circuit?
Consider tightening tolerances, and keep increasing maxsideband till the pnoise result converges.