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Nov 30th, 2021, 6:37am
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[Help] SpectreRF pnoise simulation: sampled output noise of a chopping amplifer (Read 78 times)
designer_ring
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[Help] SpectreRF pnoise simulation: sampled output noise of a chopping amplifer
Oct 26th, 2021, 3:10am
 
Hello, everyone!
For a sampled output noise of a choping amplifer: how to simulate "chopping modulation" and "sampling aliasing" together?

For a chopping amplfier, choping frequency=1MHz, PSS is automaticaly set to 1MHz by software:
1) in timeaverage pnoise simulation, 1/f noise is moved to choping frequency; This is expected result.
2) in sampled pnoise simulation, we observe the aliasing due to sampling. But 1/f noise is not modulated and still in low frequency; This is not all my expected result.

The reason why I try to use sampled simulation is that:
1) A oversampling ADC is after this choping amplfier. What I want to calculate is "discrete sampled noise" rather than "continues noise".
2) I want to observe both "choping mudulation" and "sampling alising".

My thinking:
We know sampling frequency must at least twice lager than signal frequency,after choping, the output signal is actually 1MHz. But in sampled pnoise simultion the sampling frequency seems also to be 1MHz (PSS frequency). The sampled pnoise simulation gives the result that the 1/f noise is not moved to choping frequency, but it does show alasing due to 1MHz sampling.

My Question:
1) I think if sampling frequecy is 2MHz, then I could get correct sampled output noise, is this possible in spectreRF?
2) How to simulate "chopping modulation" and "sampling aliasing" together?
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« Last Edit: Oct 26th, 2021, 5:15pm by designer_ring »  
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designer_ring
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Re: [Help] SpectreRF pnoise simulation: sampled output noise of a chopping amplifer
Reply #1 - Oct 26th, 2021, 8:48pm
 
I got solution!!!

pnoise -> option -> additonalParams "sampleratio=2"
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