Christopher J Cronin

US Patent:

7263090, Aug 28, 2007

Filed:

Jul 23, 2002

Appl. No.:

10/200450

Inventors:

Christopher J. Cronin - Monrovia MD, US
Ramakrishnan Balasubramanian - Gaithersburg MD, US

Assignee:

Viasat, Inc. - Carlsbad CA

International Classification:

H04J 3/06

US Classification:

370350, 370509

Abstract:

A method and system of synchronizing two nodes of a network uses a demodulated output signal of a time division multiplex (TDM) demodulator to perform frequency and timing synchronization independently. Frequency synchronization is performed without using a program clock reference, by detecting a symbol timing loop error of the TDM demodulator. The error is filtered by an oscillator control loop filter if the error is within a predetermined range. Thus, an output voltage of a digital to analog converter that receives the filtered output controls an oscillator. In the timing synchronizer, an error between a program clock reference (PCR) and a value of a counter in the terminal is computed if the PCR is a not a first PCR, and the error is filtered with a timing loop control filter. A processor then adjusts a value of the counter in the terminal based on the filtered output.