Pll jitter calculation

1. What is jitter in PLL?
2. How is jitter time calculated?
3. What causes jitter in PLL?
4. How does PLL reduce jitter?

What is jitter in PLL?

4.2 Jitter Basics

One of the most important specifications in microprocessor PLLs is the jitter specification. Li short, jitter is a statistical measure of the deviation of the actual PLL clock edges from an ideal clock edges.

How is jitter time calculated?

The standard procedure for measuring period jitter involves randomly measuring the duration of one clock period 10,000 times, and using the recorded data to calculate the mean, standard deviation and peak-to-peak values.

What causes jitter in PLL?

Jitter is a time deviation of a signal transition from its ideal position in time. It can be caused by many different factors, including PLL loop noise, thermal noise, cross talk, power supply ripply. It can be characterized by using multiple terminology.

How does PLL reduce jitter?

A jitter attenuating PLL can be used to filter noise from the input clock and produce a low jitter output clock. Reducing the loop filter bandwidth increases the amount of jitter attenuation on the reference clock, transferring less jitter from the input to the output.