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Measurements >> Phase Noise and Jitter Measurements >> Transient Noise to build Phasenoise curve
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Message started by Stefan on Sep 21st, 2007, 2:15pm

Title: Transient Noise to build Phasenoise curve
Post by Stefan on Sep 21st, 2007, 2:15pm
Hi,

has anybody of you used a transient noise simulation to calculate a phasenoise curve for an Oscillator or PLL ?
I know that this is error prone and RF measures would be more appreciated, but in this special case we simply can do only transient simulations.

Anyone has experience with this ?

Regards,

Stefan

Title: Re: Transient Noise to build Phasenoise curve
Post by Sarig on Dec 6th, 2007, 10:10am
Hi,
I have the same problem. did you find the answer ?
Erez

Title: Re: Transient Noise to build Phasenoise curve
Post by neoflash on Dec 16th, 2007, 6:34am
Since phase noise is a random process, it requires very large amount of data to do statistical analysis. So, if you run transient, you make sure you do very long time and have enough of data for jitter analysis.

I don't think it is feasible way.

Title: Re: Transient Noise to build Phasenoise curve
Post by Sarig on Dec 17th, 2007, 1:32pm
Hi,
We need to do Tranisent noise and find the phase noise because for example for Fractional N this is the only why to find the Phase noise.
Also for VerilogA models you need to do many changes i order to run PSS+PNoise.
So if you want you can for PLL-> Down convert to I and Q -> Filter -> bring to Matlab using:
x=I+jQ
find the angel -> unwarp -> fit to line and PSD it.

you are right that you need long long sim (1mS for GHz VCO)
Sarig.

Title: Re: Transient Noise to build Phasenoise curve
Post by kDaniu on Apr 30th, 2008, 4:55pm

neoflash wrote on Dec 16th, 2007, 6:34am:
Since phase noise is a random process, it requires very large amount of data to do statistical analysis. So, if you run transient, you make sure you do very long time and have enough of data for jitter analysis.
I don't think it is feasible way.

you have to say - How much that your 'for a long time'?
that transient noise in Spectre has a behavior to degenerate (in the case of statistical quality (randomness))

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