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Design >> Mixed-Signal Design >> chopper stabilization simulation?
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Message started by vakilia on Oct 18^th, 2004, 12:18pm

Title: chopper stabilization simulation?
Post by vakilia on Oct 18^th, 2004, 12:18pm

Hi,

As we know, the chopper stabilization technique is generally used to avoid low-frequency noise effect by up-converting (modulating) the baseband signal and then down-converting after signal amplification. So there is a modulation frequency (Fchs) involved with this scheme.
Now, considering a sampled data system that has a sampling clock (Fs) larger than Fchs.
How can I simulate the frequency response of this discrete-time system using PSS when Fs is not a multiple of Fchs and therefore, I have two indipendant clock sources?
Is it a must to generate Fsch from Fs (using dividers) to be able to use PSS?

Thank you,
Babak

Title: Re: chopper stabilization simulation?
Post by Ken Kundert on Jul 6^th, 2005, 10:56pm

You can use SpectreRF to compute the frequency response of a chopper. To do so, turn off the input signal (Fchs) and perform a PSS analysis with only the clock (Fs) applied. Then specify pacmag=1 on the input source and perform a PAC analysis. In this way the input is applied by as a small signal and so its frequency is not constrained.

-Ken