The effect of fast jitter on a latch-type phase comparator in a phase-locked loop

When a latch-type phase comparator is used in an analog phase-locked loop, the fast jitter (phase jitter) present in the stopband of the low-pass filter is superimposed on the input signal in the stop region, affecting phase comparator performance. In the present paper, the effect of fast jitter is studied analytically and experimentally. The results indicate that the latch-type phase comparator has the unique characteristic of discontinuous variation in the positive region, causing it to be nonlinear in the presence of positive sine wave fast jitter. Furthermore, extension of the positive slope portion prevents occurrence of false modes.