We analyze the effect of Subscriber-end timing recovery Circuit jitter on the performance of two types of adaptive echo cancellers that can be used for full-duplex digital transmission on two-wire subscriber loops. Under severe echo-to-far-end signal ratios, echo canceller performance is found to be quite sensitive to high-frequency jitter components. Satisfactory performance with respect to jitter requires that a narrow-band phase-locked loop, rather than a single-tuned high- Q filter, be employed for timing recovery.
['David D. Falconer']
Timing Jitter Effects on Digital Subscriber Loop Echo Cancellers: Part I--Analysis of the Effect