IP Library Granted Patent US 7,646,686
Granted Patent B2
US 7,646,686 · App. 10/981,869 · Granted Jan 12, 2010

Recording/reproduction apparatus which adjusts recording power based on a partial response maximum likelihood (PRML) technique

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Quick Facts
Patent No.
US 7,646,686
App. No.
10/981,869
Granted
Jan 12, 2010
Kind
B2
Abstract

A recording/reproduction apparatus, comprising a first recording section for recording test information onto a medium using at least one recording power, a reproduction section for reproducing at least one test signal indicating the test information from the medium, and a second recording section for recording information onto the medium using one of the at least one recording power. The reproduction section comprises a decoding section for performing maximum likelihood decoding of the at least one test signal and generating at least one binary signal indicating a result of the maximum likelihood decoding, a calculation section for calculating a reliability of the result of the maximum likelihood decoding based on the at least one test signal and the at least one binary signal, and an adjustment section for adjusting a recording power for recording the information onto the medium to the one recording power based on the reliability.

Claims (18)

1. A recording/reproduction apparatus, comprising:

a first recording section for recording at least one piece of test information onto a medium using at least one recording power;

a reproduction section for reproducing at least one test signal indicating the at least one piece of test information from the medium; and

a second recording section for recording information onto the medium using one of the at least one recording power,

wherein the reproduction section comprises:

a decoding section for performing maximum likelihood decoding of the at least one test signal and generating at least one binary signal indicating a result of the maximum likelihood decoding;

a calculation section comprising:

a differential metric detection section for calculating a reliability of the result of the maximum likelihood decoding based on a state transition sequence identified by the at least one binary signal and a result of calculation of a Euclid distance between the at least one test signal and at least one target value used in the maximum likelihood decoding;

a determination section for determining whether or not a recorded state is normal based on the reliability calculated by the differential metric detection section; and

an adjustment section for adjusting a recording power for recording the information onto the medium to the one recording power based on the reliability calculated by the differential metric detection section.

2. A recording/reproduction method, comprising:

recording at least one piece of test information onto a medium using at least one recording power;

reproducing at least one test signal inddicating the at least one piece of test information from the medium; and

recording information onto the medium using one of the at least one recording power,

wherein the reproducing step comprises;

performing maximum likelihood decoding of the at least one test signal and generating at least one binary signal indicating a result of the maximum likelihood decoding;

calculating a reliability of the result of the maximum likelihood decoding based on a state transition sequence identified by the at least one binary signal and a result of calculation of a Euclid distance between the at least one test signal and at least one target value used in the maximum likelihood decoding; and

adjusting a recording power for recording the information onto the medium to the one recording power based on the reliability.

Assignments (2)
CHANGE OF NAME Recorded Nov 24, 2008
From: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
To: PANASONIC CORPORATION
Reel/Frame 021897/0653 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 14, 2005
From: MIYASHITA, HARUMITSU; NAKAJIMA, TAKESHI; SHOJI, MAMORU; HINO, YASUMORI
To: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Reel/Frame 015709/0316 →