Analysis of Phase Noise Performance in Reference Clocks and its Impact on Jitter in High-speed Digital Communications

摘要

The quality of reference clocks can be a limiting factor in the overall performance of a digital communications system. Jitter performance and subsequently system bit-error-ratio (BER) metrics can be related directly to the performance of the reference clock. The phase noise of a reference clock is a measure of the spectral purity and stability of the reference clock. All clocks exhibit some level of phase noise, which has a direct relationship to the jitter of transmitted data. This paper addresses the sources of jitter in reference clock systems, provides insight into the way receivers respond to the noise, and presents measurement approaches to quantify clock noise at the system level.