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Simulators >> RF Simulators >> Settings of PSS/PNoise
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Message started by Thomas on Jan 17^th, 2007, 4:45am

Title: Settings of PSS/PNoise
Post by Thomas on Jan 17^th, 2007, 4:45am

Dear all,

I'm try to simulate a chopping amplifier with an input frequency of 500Hz and chopping frequency of 100kHz. And I have some questions concerning the settings of PSS and PNoise.

For the PNoise analysis I have set the sidebands to 201 to include all frequencies of interests and the reference side-band to 0. Is this right???

For PSS I have set the harmonics also to 201. Is this necessary or is it possible to set this value independently from the sidebands?

Thanks helping me

/Thomas

Title: Re: Settings of PSS/PNoise
Post by Andrew Beckett on Jan 17^th, 2007, 6:52am

Thomas,

Your settings imply that you have a large signal input (for the 500Hz signal). You probably don't need that unless this signal is large enough to cause distortion, and you want to analyses the intermodulation of the noise with that distorting input.

So, probably you just want to make the input signal a small signal (or DC for the purposes of noise analysis). This means your PSS will run faster, and also you then need as many harmonics/sidebands of the chop frequency as are likely to contribute noise. Also, the reference sideband would be 0, since the input and output frequencies are the same - there is no shift of the specified output sweep frequency needed in order to get to the input frequency.

If you've not done so, you might want to read http://www.designers-guide.org/Analysis/sc-filters.pdf as much of what is said there would apply to a chopping amplifer.

Best Regards,

Andrew.

Title: Re: Settings of PSS/PNoise
Post by Thomas on Feb 13^th, 2007, 1:52am

Hello Andrew,

thanks for your helpful advises. Indeed it was a goog idea to set the input signal to DC since it is a very small signal. The PSS and Pnoise runs now much faster.

Thanks a lot!

/Thomas