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:
Feb. 24, 1998
Filed:
Sep. 23, 1996
Applicant:
Inventors:
Assignee:
Fujitsu Limited, Kawasaki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ; G11B / ;
U.S. Cl.
CPC ...
369 4427 ; 369 58 ;
Abstract
A CD and an MO cartridge are accessed by a pickup of the same optical system, thereby allowing 4-split photodetectors to receive a medium return light to obtain a tracking error detection signal. Upon recording and reproduction of the MO cartridge, a tracking error detecting circuit for MO detects a first tracking error signal by a push-pull method on the basis of light reception signals obtained from the pickup. Upon reproduction of the CD, a tracking error detecting circuit for CD detects a second tracking error signal by a heterodyne method on the basis of the light reception signals obtained from the pickup.