Patent Number: 6,167,048

Title: Clock recovery for video communication over ATM network

Abstract: A method of clock recovery from a fast packet switched asynchronous network wherein a time stamp is transmitted over a network that has variable delay, involves maintaining an input counter at a sending device. The counter has a value dependent on an input clock. The value of the input counter is periodically transmitted over the network to a receiving device. A local counter at a receiving device has a value dependent on a local clock. The received value sample x.sub.i is compared with the local sample y.sub.i to derive the difference e.sub.i. The local clock frequency f.sub.j is adjusted such that the average of Emin.sub.j, where Emin.sub.j is the minimum of a block of error samples e.sub.i, remains close to a predetermined value, preferably zero. The clock recovery method is particularly suitable for MPEG2 video transmitted over ATM.

Inventors: Law; Randy A. (Surrey, CA), Cox; Neil B. (Burnaby, CA), Froese; Edwin L. (Surrey, CA)

Assignee: Alcatel Networks Corporation

International Classification: H04J 3/14 (20060101); H04L 7/00 (20060101); H04L 7/04 (20060101); H04L 7/06 (20060101); H04L 12/56 (20060101); H04N 7/50 (20060101); H04J 003/14 (); H04L 007/00 ()

Expiration Date: 12/26/2017