|Sources of Phase Noise and Jitter in Oscillators|
by Ramon Cerda, VP of Engineering
The output signal of an oscillator, no matter how good it is, will contain all kinds of unwanted noises and signals.
Some of these unwanted signals are spurious output frequencies, harmonics and sub-harmonics, to name a few.
The noise part can have a random and/or deterministic noise in both the amplitude and phase of the signal.
Here we will look into the major sources of some of these unwanted signals/noises.
Oscillator noise performance is characterized as jitter in the time domain and as phase noise in the frequency domain.
Which one is preferred, time or frequency domain, may depend on the application.
In radio frequency (RF) communications, phase noise is preferred while in digital systems, jitter is favored.
Hence, an RF engineer would prefer to address phase noise while a digital engineer wants jitter specified.
Note that phase noise and jitter are two linked quantities associated with a noisy oscillator and, in general, as the phase noise increases in the oscillator, so does the jitter...