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. 30, 1998
Filed:
Aug. 15, 1995
Kenji Tanaka, Otokuni-Gun, JP;
Teruhisa Miyata, Otokuni-Gun, JP;
Akira Miyake, Toride, JP;
Nobuhiro Umebayashi, Tsukuba, JP;
Hitachi Maxell, Ltd., Osaka-Fu, JP;
Abstract
A magnetic disk has optical servo grooves formed at specified intervals along data tracks so that variations in reflected light of light applied to the grooves are detected so as to allow a magnetic head to perform tracking servo. A level difference between a regenerative signal and a fundamental wave of modulation noise during reads of data recorded on the data tracks (4A, 4B) is set to 28 dB or more. Thus, comb-shaped modulation in a regenerative signal due to optical servo grooves is reduced so that output drop of the regenerative signal is suppressed and deterioration of window margin and the like is lessened.