digital processing of SONET pointers

摘要

In a method of desynchronizing asynchronous subscriber traffic conveyed through a synchronous network, an STS/STM signal encapsulating the subscriber traffic is received at a terminating node of the network. The STS signal includes a timing estimate (F) indicative of a frequency difference between a data rate (f1) of the subscriber traffic and a Tx local reference frequency (f2) of an originating node of the network. The encapsulated subscriber traffic is buffered within an elastic store. Each successive payload pointer of the received STS/STM signal is processed to generate a corresponding pointer parameter. These pointer parameters are digitally filtered to derive an estimated relationship (”f) between the Tx local reference frequency (f2) and an Rx local reference frequency (f3) of the terminating node. The local reference frequency (f3) is then adjusted using the timing estimate (F) and the estimated relationship (”f), to generate a recovered clock signal having a frequency (f4) that substantially equals the data rate (f1) of the subscriber traffic. Finally, the buffered asynchronous subscriber traffic is read at a timing of the recovered clock signal.