[Tool] Calculate Clock RMS and Peak Jitter from Phase Noise

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[Tool] Calculate Clock RMS and Peak Jitter from Phase Noise

Find a good app note from Maxim about clock jitter and phase noise conversion. It has detailed derivation. In summary, carrier spectrum is like below:

clk_pnj1

Then we can use below to calculate RMS clock jitter:

clk_pnj2

 

In spreadsheet, we use linear approximation where a is slope rate for that linear region.

clk_pnj3

 

Spreadsheet uses the following measured clock phase noise as an example.

clk_pnj4

 

 

So RMS clock jitter due to 10Hz-100KHz band noise is given in cell F15. Peak-to-Peak jitter is 7.44 * RMS jitter assuming noise is Gaussian dist.

I also like to see how much contribution floor noise (noise in band >100KHz) can make to jitter/total-noise. Turns out quite a lot. But normally osc output is filtered so this band noise can be dropped.

 

 

 
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