Jitter and phase noise are essentially manifestations of the same physical phenomenon in two different domains (time domain vs. frequency domain), and they can be converted to each other through mathematical transformations. In a nutshell, phase noise is the “spectral view” of jitter in the frequency domain, while jitter is the “accumulated result” of phase noise in the time domain.

It is therefore important to note that phase noise requires an offset frequency range, and jitter also requires bandwidth for meaningful test results. For example, for audio applications, phase noise needs to cover a wider range, such as 1Hz to 100kHz offset. Similarly, the jitter test bandwidth should also meet the requirements of the audio application. Many audio devices use jitter bandwidths specified in the communications field. For example, a typical jitter bandwidth in the communications industry is 10kHz to 20MHz, which is too low for audio applications, making this jitter value meaningless.