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:
Mar. 22, 2005
Filed:
Aug. 12, 2002
Sevgui Hadjihassan, Kanata, CA;
Tom M. Luk, Ottawa, CA;
Sevgui Hadjihassan, Kanata, CA;
Tom M. Luk, Ottawa, CA;
Nortel Networks Limited, St. Laurent, CA;
Abstract
Methods and apparatus are provided for adjusting slicing parameters, such as a voltage threshold and a phase sampling point, used in recovering 1's and 0's from a signal so as to reduce a bit error rate (BER) of the signal. The BER is modelled as a second order polynomial of the slicing parameters. The BER is repeatedly determined from a Forward Error Correction corrected bits counter. For each BER measurement the model is updated, using for example a recursive least squares fit. New values of the slicing parameters are then determined by carrying out an iteration of an optimization, such as a Levenberg-Marquardt optimization, using the model. The new values of the slicing parameters are passed to a Clock and Data Recovery module. Various conditions are checked before updating the model or determining the new values of the slicing parameters, such as changes in signal power or high BERs which exceed the error correction capabilities of the forward error correction.