Patent ID: 6990109

Claim:
A method of providing a clock recovery function in the receiving entity of constant bit-rate (CBR) communication signals transported over an asynchronous transfer mode (ATM) or ATM-like network, in order to provide reliable voice and voice-band data communications in a manner that is effectively transparent to an associated modem serving customer premises equipment, said method comprising the steps of: (a) writing ATM cells received over said network in a cell buffer and reading out previously stored cells from said cell buffer for delivery to a communication circuit; (b) generating an input clock signal having transitions associated with times of receipt of ATM cells from said network; (c) generating a reference clock signal based upon a relatively high frequency service clock signal from which an output clock signal, having a frequency corresponding to a source clock frequency for transmitting said ATM cells over said network, may be derived; and (d) coupling said input clock signal and said reference clock signal to a phase detector of a phase locked loop (PLL), the output of which is used to control a clock signal generator to which said service clock signal is applied, and causing said PLL to generate said output clock signal in accordance with the number of cycles of said service clock signal that occur between respective transitions in said input clock signal and said reference clock signal.