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:
Jun. 20, 1989
Filed:
Oct. 19, 1987
Hitachi, Ltd., Tokyo, JP;
Abstract
A constant linear velocity disk rotating apparatus for rotating a disk storing data recorded therein substantially at fixed linear recording speed detects a signal recorded in the disk by signal detecting means, obtains a control signal through the comparison of phase of the signal detected from the disk and that of a reference signal by phase comparing means, and controls the rotating speed of the disk on the basis of the control signal. To maintain the sensitivity of phase error detection which tends to vary in proportion to the radial position r of the signal detecting means relative to the disk at a fixed level, the gain of the phase control system is regulated in inverse proportion to the radial position r of the signal detecting means according to the output of detecting means which detects the rotating frequency or period of the disk. The control signal provided by the phase comparing means is applied to disk driving means after regulating the gain thereof by varying the duty factor in transmitting the control signal to the disk driving means.