Self-Noise in Synchronizers

Synchronization of narrow-band data signals is plagued by self-noise arising from the randomness of the data stream. The disturbance can be resolved into in-phase and quadrature components with respect to the recovered carrier or clock. Only the quadrature component necessarily contributes to phase jitter of the recovered reference. Spectrum of the quadrature component, in many cases, vanishes at the reference frequency. Circuit precautions are needed to avoid cross coupling the in-phase disturbance into phase jitter.