SYNCHRONOUS DIGITAL SIGNAL TO ASYNCHRONOUS DIGITAL SIGNAL DESYNCHRONIZER

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, e.g., a SONET STS-1 signal. The improved jitter performance results from the use of a unique dynamic bit leaking arrangement in conjunction with a digital phase locked loop and desynchronizing elastic store. An optimum bit leak interval is obtained by controllably leaking a greater number o f shorter interval STS-1 bits than the number of received pointer adjustment bits. Additionally, the affect 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 bit s to be leaked. The queue is dynamically maintained at its "static" count so that the re are always bits in the queue to be leaked at the desired optimum bit leak interval e ven in the presence of randomly received pointer adjustments.