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.

Date of Patent:
Feb. 22, 1994

Filed:

Mar. 04, 1992
Applicant:
Inventors:

Shigeko Kobayashi, Kawasaki, JP;

Akira Minami, Inagi, JP;

Shigenori Yanagi, Kawasaki, JP;

Assignee:

Fujitsu Limited, Kawasaki, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4428 ; 369 4435 ; 369 4432 ; 369 4429 ;
Abstract

A track cross signal generation circuit comprises a tracking error signal generation circuit, an offset compensation circuit, a level setting circuit, and a comparator. The comparator directly receives a tracking error signal output from the tracking error signal generation circuit without passing through the offset compensation circuit and a reference level output from the level setting circuit. Further, the comparator compares the tracking error signal with the reference level, and generates a track cross signal representing the tracks formed on an optical recording medium crossed by a beam. Namely, the gain of the tracking error signal is not affected by the offset compensation circuit even within a high-speed region of the beam. Consequently, the track zero cross signal correctly indicates tracks crossed by the beam, and correctly and stably carries out a seek operation in the high-speed region of the beam.


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