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:
Sep. 24, 1996
Filed:
Nov. 09, 1994
Yamaha Corporation, Hamamatsu, JP;
Abstract
Test EFM signal reproduced from an optical disk is converted through a slicer into binary value, and a synchronizing signal having an 11T--11T signal pattern is detected by a frame synchronization circuit. Upon detection of the synchronizing signal, a detection timing counter predicts timing when a next synchronizing signal will be detected. The respective level values at the intermediate points of the former and latter 11T sections of the synchronizing signal are sampled and held by sample and hold circuits. Once a next synchronizing signal is detected at the predicted timing, a synchronization determination circuit transfers the outputs of the sample and hold circuits to another sample and hold circuits. The outputs of the other sample and hold circuit are averaged by filters and asymmetry is calculated by an asymmetry calculation circuit. On the basis of the calculated asymmetry, a determination circuit determines an optimum recording power value.