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. 27, 2008

Filed:

Sep. 24, 2001
Applicants:

Kenji Nagashima, Kanagawa, JP;

Eiji Kumagai, Kanagawa, JP;

Satoshi Kumai, Kanagawa, JP;

Toshio Morizumi, Kanagawa, JP;

Inventors:

Kenji Nagashima, Kanagawa, JP;

Eiji Kumagai, Kanagawa, JP;

Satoshi Kumai, Kanagawa, JP;

Toshio Morizumi, Kanagawa, JP;

Assignee:

Sony Corporation, Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 7/125 (2006.01);
U.S. Cl.
CPC ...
Abstract

After the initiation of writing, an output signal from an LPF is sampled in correspondence with a portion with a predetermined pulse width of recording data, so as to obtain a pit level. In the resultant signal, its varying portions which correspond to the multi-pulse trains of the write signal are smoothed. A controller modifies a level of a target level signal to be supplied to an APC circuit in such a manner that the pit level becomes an optimum pit level which has been obtained prior to the initiation of writing.


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