Phase Noise and Jitter in Digital Electronics

Phase noise is one way to quantify timing noise in a signal, which is typically used in analog signals.  Phase noise in the frequency domain appears as jitter in the time domain.  With digital signals, jitter is the primary metric used to understand signal integrity and stability.  When dealing with digital signals, it is best to use jitter to quantify signal quality. Jitter has additional sources beyond random fluctuations in phase due to the edge rate of digital signals. 

There are several causes of jitter in digital systems like intersymbol interference (ISI) due to inadequate bandwidth and reflections, power bus noise and transients, random noise (for example, thermal noise), and crosstalk during edge transitions.  In any jitter measurement, all of these factors could be occurring simultaneously. Designers must often use simulations to try and decouple these sources of jitter, or isolated channel measurements can be used to try and determine the influence of each on jitter. 

Phase noise and jitter in digital electronics are unavoidable, but you can design to minimize things like power dropout, crosstalk, reflections, and EMI susceptibility with a complete set of system analysis tools from Cadence. 

Click here to learn more about phase noise and jitter in digital electronics. 

Team SimTech 

Cadence Design Systems