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:
Aug. 11, 1992
Filed:
Apr. 20, 1990
Applicant:
Inventors:
Alan A Fennema, Tucson, AZ (US);
Benjamin C Fiorino, Tucson, AZ (US);
Assignee:
International Business Machines Corporation, Armonk, NY (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ; G11B / ;
U.S. Cl.
CPC ...
369 4429 ; 369 32 ; 369 4426 ;
Abstract
An optical disk recorder includes disk reflectance calibration means for measuring variations in disk reflectance over the recording area of the disk. Correction factors based on measured reflectance for adjusting sensed signal level and gain reduce the effects of varying reflectance on the sensed signal. In a preferred embodiment, the sensed signal is employed as a signal in quadrature to a tracking error signal for ensuring reliable track counting in a track seeking operation. In a grooved medium, reflectance is calibrated for both grooves and mesas between the grooves.