A Time Domain Method to Measure Oscillator Phase Noise

Time domain measurement of a real oscillator output reveals non-ideal variation, commonly called jitter. This paper presents a new measurement method to test for the presence of a phase noise spur in an oscillatorpsilas output. Models for some specific classes of jitter characterize noise in the time domain, namely: random jitter (RJ); and a sub-class of deterministic jitter (DJ), sinusoidal jitter (SJ). These models and analysis of m-cycle-to-m-cycle jitter enable estimation of phase noise power spectral density characteristics for an oscillators output. Specifically, m-cycle-to-m-cycle jitter extracted from time domain measurements characterize SNR for discrete spurious phase noise. Thus, this method uses time domain measurements to estimate the effect of real noise sources, such as digital switching noise that couples to the oscillator output, and appears as phase noise spurs in the frequency domain.