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Phase noise simulation using a verilog A model (Read 2341 times)
iVenky
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Phase noise simulation using a verilog A model
Jun 17th, 2017, 5:51pm
 
Hi,

I have an ideal current source for the VCO. The thermal noise of the current source was modeled in a verilog A model using the white_noise() function. When I run pss/pnoise, I observe that phase noise of the VCO is not considering the effect of noise due to this verilogA model. Any suggestions?

I tried verifying the white_noise() verilog A model separately by running a transient noise simulation and it works.

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subtr
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Re: Phase noise simulation using a verilog A model
Reply #1 - Jun 17th, 2017, 9:42pm
 
I expect that your noise is a transient parameter which the simulator even does not recognize as noise. The PSS basically wants to find periodic steady state which might even be hindered by the noise added. I don't think PSS runs a transient noise analysis. I believe PSS gives the sensitivity function which the pnoise can use to find the spectrum. Your noise is in time domain. pnoise is an AC analysis which might not even see your verilogA being there. Probably this is the reason why you see only device noise and not the model noise.
The solution is to do a tran noise analysis and take FFT of the crossing points to get the phase noise spectrum through matlab. This will take the effect of your verilogA into consideration because measurement is done on the transient data.
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Ken Kundert
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Re: Phase noise simulation using a verilog A model
Reply #2 - Jun 17th, 2017, 10:09pm
 
My suggestion is, if you want help, you should give the model. We cannot help you if you give us no information.

-Ken
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