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:
May. 18, 2010

Filed:

Mar. 15, 2006
Applicants:

Hiromichi Oshikubo, Ibaraki, JP;

Shoji Kobayashi, Kanagawa, JP;

Osamu Hosokawa, Tokyo, JP;

Inventors:

Hiromichi Oshikubo, Ibaraki, JP;

Shoji Kobayashi, Kanagawa, JP;

Osamu Hosokawa, Tokyo, JP;

Assignee:
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03D 3/22 (2006.01);
U.S. Cl.
CPC ...
Abstract

The objective of this invention is to perform high-precision tracking error detection and tracking control using digital circuitry at relatively low speed and with a small circuit scale. Tracking servo circuit is formed as a single-chip circuit. Low-pass filters (LPF) and gain control amplifiers (GCA) of the input portion are analog circuits, while the circuits after analog-digital (A/D) converters, that is, offset cancellation circuits, equalizers (EQ), first and second phase difference detectors, adder, low-pass filter (LPF), gain control amplifier (GCA), and servo DSP are all digital circuits.


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