desynchronisierer from synchronous to asynchronous digital signals, digital signals

摘要

Improved jitter performance is realized in a desynchronizer for obtaining an asynchronous digital signal, e.g., a DS3 signal, from a received synchronous digital signal, (from 101), e.g., a SONET STS-1 signal. The improved jitter performance results from the use of a unique dynamic bit leaking arrangement (105) in conjunction with a digital phase locked loop (109,110,111) and desynchronizing elastic store (104). An optimum bit leak interval is obtained by controllably leaking a greater number of shorter interval STS-1 bits than the number of received pointer adjustment bits. Additionally, the effect of random pointer adjustments and the superposition of randomly received pointer adjustments on a periodic sequence of received pointer adjustments is minimized by employing a "static" queue of pointer adjustment bits to be leaked. The queue is dynamically maintained at its "static" count so that there are always bits in the queue to be leaked at the desired optimum bit leak interval even in the presence of randomly received pointer adjustments. IMAGE