Telcordia Technologies, Inc.

Nim K Cheung

Thomas C Banwell

William Anderson

James E Hodge

Methods and apparatuses are provided for determining characteristics of an input optical signal in an optical network. An optical signal monitoring apparatus estimates a minimum time interval between transitions in the input signal, determines a clock signal based on the estimated minimum time interval, and performs a time domain measurement on the input signal based on the determined clock signal. The optical signal monitoring apparatus samples the input signal based on the determined clock signal and determines the characteristics of the input signal.

Method and apparatus for automated time domain monitoring in optical networks

Methods and apparatuses consistent with the present invention recover a clock signal from a variable bit rate data signal by estimating, in the time domain, the bit rate of the data signal, and based on the estimated variable bit rate, determining a center frequency of a narrow-band filter for extracting the clock signal from the data signal. A clock recovery circuit consistent with the present invention extracts a clock signal from a variable bit rate data signal by estimating a minimum time interval between transitions in the data signal, generating a plurality of pulses that correspond respectively to transitions in the data signal, adjusting the duration of each of the pulses based on the estimated minimum time interval and inputting into a narrow-band filter the adjusted pulses, determining a center frequency of the narrow-band filter based on the estimated minimum time interval, and extracting in the narrow-band filter the clock signal from the adjusted pulses.

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Short Hills, NJ, United States of America

Nim K Cheung