TIMING CIRCUIT FOR MULTIPLEXING/DEMULTIPLEXING OPTICAL COMMUNICATION SIGNAL

摘要

PROBLEM TO BE SOLVED: To automatically match the selection of a multiplexing clock with a correspondent node. SOLUTION: The circuit for the node of an optical communication network is configured for multiplexing one or plural input customer signals and demultiplexing an input optical signal and the multiplexing clock and a demultiplexing clock are selected out of one or plural customer clocks recovered from one or plural customer signals, the input clock recovered from the input optical signal and a local clock generated by a local clock generator. This circuit is configured as a drop/continue configuration to select both the multiplexing clock and the demultiplexing clock and when a clock losing state to the multiplexing clock selected before is detected, a hardware based switch is executed to select a backup clock as a new multiplexing clock.