Systematic Jitter in a Chain of Digital Regenerators

An ideal "i^ital regenerator must restore the shape and timing of a received signal. A self-timed regenerator extracts the timing information from the received pulse train by means of a narrow bandpass filter t ,ued to the repetition rate. Imperfections in the regenerator and noise in the channel disturb the timing information and cause the phase of the pulse train to vary. This variation is called jitter. Jitter in self-timed repeaters has been studied for some time. Sunde 1 and DeLange 2 concluded that jitter due to random noise would not be serious. Attention then turned to jitter introduced in the timing tanks by pattern variations. Bennett 3 studied a single mistuned regenerator. Rowe 3 analyzed a long chain of tuned regenerators. S. O. Rice studied jitter due to a random pattern in a long chain of systematically detuned regenerators. The first fully developed digital regenerator intended for use in long chains became available in 1961. This was the repeater for the T1 P C M * Bellcomm, Inc. 2679