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Andrew Beckett

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Posts: 1742
Bracknell, UK

Re: phase noise and Jitter measurements in Cadence
Reply #15 - Jun 28^th, 2005, 11:03pm

Well, yes - the "P" in PSS does stand for periodic...

Note, the noise is small-signal, so you don't have to worry about that in the PSS analysis itself - it is only applied during the pnoise/psp analyses.

You can have non-periodic sources for (say) startup of the circuit - PSS will simulate these until they become periodic (or constant) - essentially you're trying to find the steady state of the circuit - so things need to either be constant or repetitive when it tries to analyse that.

Regards,

Andrew.

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chlai

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Taipei, Taiwan

Re: phase noise and Jitter measurements in Cadence
Reply #16 - Jun 29^th, 2005, 3:48am

Thank you very much, Andrew.

The problem confused me is that we use not only periodic signal but periodic noise for PSS analysis. However, that is an assumption that noise should be periodic at steady state.
Does that mean only cyclostationary noise could be applied on this vco model? Stantionary noise couldn't due to no periodical information. (So we need to use idtmod() instead of idt() in PSS analysis.)

Best regards,
Daniel Lai

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Andrew Beckett Senior Fellow Offline Life, don't talk to me about Life... Posts: 1742 Bracknell, UK	Re: phase noise and Jitter measurements in Cadence Reply #17 - Jun 29^th, 2005, 6:13am The term "periodic noise analysis" is referring to the fact that you are doing a noise analysis about a periodic steady state; it is not referring to the noise itself being periodic. Mind you, I'm not entirely sure I understood what you said in your last append. Regards, Andrew.
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chlai

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Taipei, Taiwan

Re: phase noise and Jitter measurements in Cadence
Reply #18 - Jun 30^th, 2005, 8:00pm

Hello Andrew,
Thank you very much for answering me so many questions.

Because idtmod() means to integrate the peridic signal and noise in one cycle (of period), which also means to make all input noise become cyclostationary noise.

My problem is: Can we determine all input noise (including flicker noise, white noise) become cyclic in this vco model. If the answer is no, would the vco model �generate error phase noise analysis result?
I think this is a cyclostationary noise definition question. Sorry to confuse you.

Thank you very much for your kindly interested.
Sincerely yours,
Daniel Lai

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