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, 2001
Filed:
Sep. 13, 2000
Minoru Tobita, Tokyo, JP;
Susumu Tosaka, Kanagawa, JP;
Yoshikatsu Niwa, Kanagawa, JP;
Shinichi Nakao, Kanagawa, JP;
Goro Fujita, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A frequency demodulating circuit, optical disk and preformatting device having a decoder for decoding a bit “0” and a bit “1” for reproducing address information recorded as a wobble groove. The decoder determines whether an output is a digital “1” or a digital “0” so that even if the waveform of the reproduced signal is erratic or unstable due to a defect, a digital “1” or a digital “0” can be correctly identified by utilizing window pulses. Changes in the slop of a zero cross point of the groove wobble are prevented from occurring by making the groove wobble amplitude fluctuate according to the signal frequency modulation which also greatly reduces jitter and allowing satisfactory acquisition of the address information. Oversampling clock signals of biphase bits are generated by frequency division of data clock signals. Since demodulation is accomplished with a single phase lock loop circuit in the data system using clock signals for both the data and the addresses, the configuration can be made extremely simple. By means of polarity of the playback signal mark having phase information, it is determined whether the beam that scans the optical disk is above the land or above the groove. The marks containing phase information are formed on the base disk surface solely by the on and off control of the paired cutting beams with respect to the direction of the time axis, for easy preformatting of a mark to permit acquiring (phase) position information with high precision.