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pnoise jitter and pnoise time average discrepency: what is the problem?

Hi everyone,
I try to get the jitter from a clock generator, but I also need the phase noise curve for other reasons:
- When I simulate my circuit with the pnoise/jitter method, I get a RMS Jitter in a given bandwidth of 594.386fs (Jee>RMS).
- And when I simulate with the pnoise/time average method, by calculating my Jitter from the Phase Noise curve, I get 269.2fs.

Assuming that the pnoise>PM>Phase Noise plot is the IEEE definition, say Single-Sideband-to-Carrier Ratio, so-called L(df), "L-script of df",
I compute the RMS jitter as follows in my calculator:
[1 / sqrt(2)*pi*f0] * sqrt{ INTEGRAL[ L(df).df ] }

Of course, here L(df) is converted in linear, L(df)=10^LdBc(df)/10

In your opinion what do I miss??

Thanks a lot in advance for your help!

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Frank Wiedmann over 5 years ago

I suggest that you take a look at https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O0V000009EStcUAG
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skylink over 5 years ago in reply to Frank Wiedmann

Thanks Frank; but I do not know what is my "Host ID" to connect...
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Frank Wiedmann over 5 years ago in reply to skylink

That's usually the Host ID of your license server for the Cadence software. You should be able to get it from the CAD support of your company.
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skylink over 5 years ago in reply to Frank Wiedmann

Ok fine, thanks.

So to sum up, we'd rather use the "jitter" analysis as "with noisetype=timeaverage, you measure the average noise power over the entire cycle of the input. It includes the noise

during the high state, low state, (almost noiseless) and both transitions (majority of the noise).".

Obviously the time average analysis does not suit to a a phase noise analysis for square waveforms...

Thank you guys for your help !

Have a nice day.
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skylink over 5 years ago in reply to Frank Wiedmann

Ok fine, thanks.

So to sum up, we'd rather use the "jitter" analysis as "with noisetype=timeaverage, you measure the average noise power over the entire cycle of the input. It includes the noise

during the high state, low state, (almost noiseless) and both transitions (majority of the noise).".

Obviously the time average analysis does not suit to a a phase noise analysis for square waveforms...

Thank you guys for your help !

Have a nice day.
Cancel
Vote Up 0 Vote Down

Cancel

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