Information reproduction apparatus and information reproduction method
AssigneeHitachi, Ltd.
InventorsHiromi Kudo, Hiroyuki Minemura, Akemi Hirotsune, Harukazu Miyamoto
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Abstract
Disclosed here is an apparatus and method for realizing write/read of mass information by reducing cross-talk components that are apt to increase in narrow tracks when various disturbances and variations are recognized. In order to achieve the above object, the apparatus is provided with a plurality of equalizers for correcting frequency characteristics of signals reproduced from a plurality of spots, then outputs from those equalizers are subjected to a computing process to correct tap coefficients of the equalizers sequentially so as to minimize the influence of the subject cross-talk, thereby realizing stable reduction of the cross-talk components.
Claims20
An information reproduction apparatus, comprising:
- means for forming a first beam spot and a second beam spot in an information recording medium;
- a first detector for detecting a reflected beam from said first beam spot;
- a second detector for detecting a reflected beam from said second beam spot;
- a first equalizer for adjusting at least a frequency characteristic of an output signal from said first detector;
- a second equalizer for adjusting at least a frequency characteristic of an output signal from said second detector;
- an arithmetic circuit for computing an output from both of said first and second equalizers respectively;
- a decoding block for decoding information recorded on said information recording medium according to said output from said arithmetic circuit;
- a target signal generator for generating a target signal from said output from said decoding block;
- a compensation value generator by comparing an output level of said target signal generator with an output value of said arithmetic circuit to compute a compensation value of a tap coefficient of said first equalizer and/or second equalizer;
- and
- input means for inputting said compensation value to said first equalizer and/or second equalizer.
An information reproduction apparatus, comprising:
- means for forming a first beam spot and a second beam spot in an information recording medium;
- a first detector for detecting a reflected beam from said first beam spot;
- a second detector for detecting a reflected beam from said second beam spot;
- a first equalizer for adjusting at least a frequency characteristic of an output signal from said second detector;
- an arithmetic circuit for computing an output from both of said first detector and said first equalizer respectively;
- a second equalizer for adjusting at least a frequency characteristic of an output signal from said computing circuit;
- a decoding block for decoding information recorded on said information recording medium according to said output from said second equalizer;
- a target signal generator for generating a target signal from an output of said decoding block;
- a compensation value generator for comparing an output level of said target signal generator with an output value of said arithmetic circuit to compute a compensation value of a tap coefficient of said first equalizer and/or second equalizer;
- and
- input means for inputting said compensation value to said first equalizer and/or second equalizer.
An information reproduction method, comprising:
- a step of forming a main beam spot and one or more sub beam spots on an information recording medium;
- a step of detecting a reflected beam from said main beam spot in a first detector and a reflected beam from a sub beam spot in a second detector;
- a step of adjusting at least a frequency characteristic of an output signal from said second detector in a first equalizer;
- a step of computing an output from both of said first detector and said first equalizer respectively in a computing circuit;
- a step of adjusting at least a frequency characteristic of an output signal from said computing circuit in a second equalizer;
- a step of decoding information recorded on said information recording medium according to an output from said second equalizer in a decoding block;
- a step of generating a target signal from an output of said decoding block in a target signal generator;
- a step of comparing an output level of said target signal generator with an output value of said computing circuit to compute a compensation value of a tap coefficient of said first equalizer and/or second equalizer in a compensation value generator;
- and
- a step of inputting said compensation value to said first equalizer and/or second equalizer.
Dependencies are inferred from the claim text.