Jitter - How to Characterize Your Oscillator or Clock Source


You can plot instantaneous frequency using freq(). You can plot the cycle-to-cycle jitter using period_jitter(). That gives you a nice waveform containing all the sample values.

But, now, you need to report the standard-deviation of the samples. What can you do?

Fortunately, the ViVA Calculator has you covered.

Change default from Population to Sample and Set Continuous to No so that, in the the buffer, you see something like:

stddev(period_jitter(clip( VT("/clk") 200n nil) "rising"  ?mode "auto"   ?binSize 0 ?xName "time"   ?outputType "plot"  ) ?type "sample" ?continuous nil )

And you're done.

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