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:
Oct. 30, 2007
Filed:
Jul. 02, 2004
Tatsushi Katayama, Kanagawa, JP;
Tatsushi Katayama, Kanagawa, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An apparatus is provided in which a parameter of Viterbi decoding is adjusted on the basis of a metric difference for evaluation of PRML signal quality to increase the error rate even when using a medium on which recording is performed under a large-distortion condition. When a reproduced signal is binarized by maximum likelihood decoding such that a state transition sequence most probable to be correct of m kinds of state transition sequences from a first state at time n−1 to a second state at time n is selected, a metric difference between the most probable state transition sequence and a second most probable state transition sequence at a predetermined time is computed, and a parameter (a reference amplitude value or a metric) of a maximum likelihood decoder is corrected on the basis of the metric difference to optimize maximum likelihood decoding operation.