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:
Jan. 08, 1991
Filed:
Jul. 14, 1989
Norikazu Takayama, Odawara, JP;
Nobuyoshi Ushijima, Odawara, JP;
Tetsuzo Kobashi, Odawara, JP;
Masahiko Sato, Odawara, JP;
Yoshihiko Yano, Hiratuka, JP;
Jun Isozaki, Kashiwa, JP;
Kousuke Fujii, Koganei, JP;
Yoshinobu Kudoh, Minamiasigara, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A method of forming servo information in a magnetic disk apparatus of a sector servo system. Servo information is recorded in advance at the beginning of each of the sectors, and includes a DC erase signal, a track address signal and a burst signal. The track address signal indicates on which track of the magnetic disk the sector is located, and is formed by expressing the track address in Gray code and interleaving a dummy code into the Gray code. Servo information is recorded using an NRZI system or an RLL coding method. Servo information in which the dummy code is interleaved is decoded after the dummy code is removed at the time of demodulation.