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a question about pss+pnoise simulation in a chopper-aplifier (Read 1448 times)
ehsan_nazarzadeh
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a question about pss+pnoise simulation in a chopper-aplifier
Jul 20th, 2016, 11:51pm
 
I try to simulate a chopper instrumentation amplifier. Chopping frequency is 5 KHz and cut-off frequency is 700 Hz. I use pss+pnoise analysis to see the noise spectrum and measure the integrated noise, but it seem to be wrong. Is it necessary to put an ideal “Sample-and-Hold” circuit in chopper-amplifier structure and then run pss+pnoise analysis? If “YES”, then which sampling frequency should I choose? If “NO”, then what are the correct settings of pss+pnoise analysis?
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Ken Kundert
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Re: a question about pss+pnoise simulation in a chopper-aplifier
Reply #1 - Jul 24th, 2016, 12:59am
 
Seems to be wrong? That is rather vague. Perhaps you could elaborate?

My experience with these types of simulationsis that you need to be careful that the interpolation of the flicker noise by the waveform tool does not corrupt the result. Make sure you have several analysis points below the flicker noise corner frequency.

To know whether you need to sample the output of your circuit, you need to think about the circuit that follows the chopper. If is a sampling circuit, then you should sample.

You do not need to build a sample and hold. The simulator can sample the result for you, though the interface is rather awkward.

-Ken
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