# PhaseNoiseToJitterConversion_OldExcelVersion

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```					            CALCULATING JITTER FROM PHASE NOISE PROFILE
Sam Wetterlin

The RMS value of period-to-period jitter is the standard deviation of the fluctuations in period length
caused by phase modulation. It is the same concept as phase noise, except that instead of looking
at phase variations, it looks at time variation. The time variation is a more fixed measure; how much
phase variation corresponds to a given time variation depends on frequency.

Enter the carrier frequency, four offsets at which phase noise is known, and the phase noise (L(f)
at each of offsets points. The jitter will be calculated automatically.

The calculation can be done in reverse (calculate phase noise from jitter) by trial and error. A simple
approach is to try various levels of flat noise until the desired jitter is produced. Remember that
jitter is measured in a certain frequency range, so use appropriate offsets.

If you don't need all four points, simply increase the extras by 1Hz and keep L(f) the same as your final
value. If you repeat two frequencies exactly, or make L(f) rise with a tiny frequency change,
you will get a divide by zero error.

The jitter calculation includes the bandwidth from the first specified offset to the last.

Carrier Frequency           600 MHz

Offset (Hz)                  10          100         1,000        10,000         10,001
L(f) in dbc                  -60          -75           -85           -95            -95
Change/decade              -15.0        -10.0         -10.0           0.0            N/A

Jitter=         1.99 ps RMS

Source:     Maxim App Note 3359
(With correction to integral of f^(a/10) when a=-10; integral is natural log)

```
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