The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 27, 2004
Filed:
Mar. 29, 2000
Applicant:
Inventors:
Edward Whittaker, Bishops Stortford, GB;
Darrell Smith, Bishops Stortford, GB;
Paul Wilson, Hertford, GB;
Assignee:
Nortel Networks Limited, St. Laurent, CA;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04B 1/006 ;
U.S. Cl.
CPC ...
H04B 1/006 ;
Abstract
An optical receiver arrangement comprises a phase locked loop incorporating a voltage controlled oscillator whereby the loop can be matched in frequency to a received signal frequency. A frequency detector associated with the loop produces an output comprising first or second pulses indicative of whether the loop frequency is above or below the received signal frequency. A control circuit determines a time averaged measure of difference between the loop frequency and the received signal frequency, and issues a loss of lock alarm if this averaged difference exceeds a predetermined value.