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:
Jul. 20, 1999

Filed:

Dec. 20, 1996
Applicant:
Inventors:

Takashi Sasaki, Kawagoe, JP;

Kazuhiro Kiyoura, Kawagoe, JP;

Alex Bradshaw, Kawagoe, JP;

Koichiro Haraguchi, Kawagoe, JP;

Takeshi Matsumoto, Kawagoe, JP;

Tomoko Miyagawa, Kawagoe, JP;

Hideaki Yoshimura, Kawagoe, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4425 ; 369 4411 ; 369 4423 ; 369 4426 ; 369 4428 ; 369 4429 ; 369 4432 ; 369 4435 ; 702 66 ;
Abstract

An unbalanced waveform of a tracking error signal is automatically corrected within a short period of time. A peak value and a bottom value of a tracking error signal are obtained by a peak-hold circuit and a bottom-hold circuit, respectively. Based on the peak value and the bottom value, an amount of offset measured from a reference level and an amplitude of the tracking error signal are computed. An adjustment value is computed for correcting the unbalance between the peak value and the bottom value based on the amount of offset and the amplitude of the tracking error signal. The adjustment value is fed back to a tracking balance circuit so that the waveform of the unbalanced waveform of the tracking error signal is corrected.


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