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:
Jul. 01, 2003
Filed:
Jan. 14, 1997
Yasuhiro Hayashi, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A laser beam is irradiated from a pickup head on a disk. Light reflected by the disk is detected by the pickup head. The data is binarized by a data slice circuit, and a synchronizing clock and a synchronizing signal are extracted by a PLL and synchronizing signal separation circuit. The center frequency of the voltage controlled oscillator of the PLL and synchronizing signal separation circuit continuously changes according to a control voltage. A disk motor control circuit continuously changes the rotation speed of the disk in accordance with a control instruction from a system controller. The disk rotates at the highest rotation speed at which a data read operation is normally performed. The characteristics of the voltage controlled oscillator change in correspondence with the rotation speed of the disk.