Signal quality evaluation method, information recording/reproducing system, and recording compensation method

• US 7,522,504 B2
• Filed: 05/05/2006
• Issued: 04/21/2009
• Est. Priority Date: 11/09/2001
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nagai, Yuji, Ogawa, Akihito, Kashihara, Yutaka
• Primary Examiner(s): HUBER, PAUL W
• Application Number:
  US11/418,245
• Publication Number:
  US 20060203679A1
• Time in Patent Office: 1,082 Days
• Field of Search: 714/795, 375/341, 369/53.31
• US Class Current: 369/53.31
• CPC Class Codes: G11B 20/10009 Improvement or modification of read or write signals
• CPC Class Codes: G11B 20/10055 using partial response filtering when writing the signal to the medium or reading it therefrom
• CPC Class Codes: G11B 20/10481 optimisation methods
• CPC Class Codes: G11B 7/0062 Overwriting strategies, e.g. recording pulse sequences with erasing level used for phase-change media
• CPC Class Codes: G11B 7/00736 Auxiliary data, e.g. lead-in, lead-out, Power Calibration Area [PCA], Burst Cutting Area [BCA], control information sector headers or adresses in prepits G11B7/00745; address data in track wobble G11B7/24082

Abstract

Signal quality evaluation is performed using a predetermined reproduction signal, a first pattern corresponding to a signal waveform pattern of the reproduction signal, and a given pattern corresponding to the signal waveform pattern of the reproduction signal and being different from the first pattern.

Claims

1. An information recording/reproducing system using a method of discriminating a signal content from an amplitude value of a signal sample, the system comprising:

means for providing a first pattern including a code bit train “

10”

or “

01”

, a second pattern including “

11”

corresponding to the code bit train “

10”

or “

01”

, and a third pattern including “

00”

corresponding to the code bit train “

10”

or “

01”

;

means for recording/reproducing the first pattern using a predetermined information recording medium;

means for calculating a recording compensation parameter Ec for the information recording medium, based on a first probability that a reproduction signal of the first pattern reproduced is recognized as corresponding to the second pattern, and a second probability that a reproduction signal of the first pattern reproduced is recognized as corresponding to the third pattern;

means for calculating a compensation amount WC based on the recording compensation parameter Ec, and

means for compensating a signal recording waveform for the information recording medium based on the compensation amount WC.

2. The system according to claim 1, wherein the recording compensation parameter Ec calculated is determined such that the first probability that the reproduction signal reproduced from the information recording medium when the first pattern is recorded on the information recording medium is erroneously recognized as corresponding to the second pattern becomes equal to the second probability that the reproduction signal reproduced from the information recording medium when the first pattern is recorded on the information recording medium is erroneously recognized as corresponding to the third pattern.

3. A recording compensation method for performing information recording on an information recording medium or for performing information reproduction from the information recording medium using a predetermined reproduction signal, a first pattern corresponding to a signal waveform pattern of the reproduction signal, a second pattern corresponding to the signal waveform pattern of the reproduction signal that is different from the first pattern, and a third pattern corresponding to the signal waveform pattern of the reproduction signal that is different from the first pattern and the second pattern, the method comprising:

determining a first distance E1 between the reproduction signal and the first pattern, a second distance E2 between the reproduction signal and the second pattern, and a third distance E3 between the reproduction signal and the third pattern;

determining a first distance difference D2=E2−

E1 between the first distance E1 and the second distance E2, and a second distance difference D3=E3−

E1 between the first distance E1 and the third distance E3;

determining a distribution of the first distance difference D2 and a distribution of the second distance difference D3 with respect to a plurality of samples of the reproduction signal;

determining a mean value M2 of the first distance difference D2 and a mean value M3 of the second distance difference D3;

determining a recording compensation parameter Ec from a relationship of (M2−

M3)/2;

determining a compensation amount WC based on the recording compensation parameter Ec; and

compensating a signal recording waveform for the information recording medium based on the compensation amount WC,

wherein said first pattern includes a code bit train “

10”

or“

01”

,

said second pattern is a pattern having the same number of bits as the first pattern, the second pattern including “

11”

corresponding to the code bit train “

10”

or “

01”

of the first pattern, and

said third pattern is a pattern having the same number of bits as the first pattern, the third pattern including “

00”

corresponding to the code bit train “

10”

or “

01”

of the first pattern.

4. A recording compensation method for performing information recording on an information recording medium or for performing information reproduction from the information recording medium using a predetermined reproduction signal, a first pattern corresponding to a signal waveform pattern of the reproduction signal, a second pattern corresponding to the signal waveform pattern of the reproduction signal that is different from the first pattern, and a third pattern corresponding to the signal waveform pattern of the reproduction signal that is different from the first pattern and the second pattern, the method comprising:

determining a first distance E1 between the reproduction signal and the first pattern, a second distance E2 between the reproduction signal and the second pattern, and a third distance E3 between the reproduction signal and the third pattern;

determining a first distance difference D2=E2−

E1 between the first distance E1 and the second distance E2, and a second distance difference D3=E3−

E1 between the first distance E1 and the third distance E3;

determining a distribution of the first distance difference D2 and a distribution of the second distance difference D3 with respect to a plurality of samples of the reproduction signal;

determining a mean value M2 of the first distance difference D2 and a mean value M3 of the second distance difference D3;

determining a recording compensation parameter Ec from a relationship of (M2−

M3)/2;

converting the recording compensation parameter Ec to a recording compensation parameter Ec′

based on frequency-of-occurrence information on various patterns determined based on properties of modulation codes;

determining a compensation amount WC based on the recording compensation parameter Ec′

; and

compensating a signal recording waveform for the information recording medium based on the compensation amount WC,

wherein said first pattern includes a code bit train “

10”

or “

01”

,

said second pattern is a pattern having the same number of bits as the first pattern, the second pattern including “

11”

corresponding to the code bit train “

10”

or “

01”

of the first pattern, and

said third pattern is a pattern having the same number of bits as the first pattern, the third pattern including “

00”

corresponding to the code bit train “

10”

or “

01”

of the first pattern.

5. A recording/reproducing system for performing information recording on an information recording medium or for performing information reproduction from the information recording medium using a predetermined reproduction signal, a first pattern corresponding to a signal waveform pattern of the reproduction signal, a second pattern that is different from the first pattern and corresponds to the signal waveform pattern of the reproduction signal, and a third pattern that is different from the first and second patterns and corresponds to the signal waveform pattern of the reproduction signal, the method comprising:

a first arithmetic section configured to determine a first distance E1 between the reproduction signal and the first pattern, a second distance E2 between the reproduction signal and the second pattern, and a third distance E3 between the reproduction signal and the third pattern;

a second arithmetic section configured to determine a first distance difference D2=E2−

E1 between the first distance E1 and the second distance E2, and a second distance difference D3=E3−

E1 between the first distance E1 and the third distance E3;

a third arithmetic section configured to determine a distribution of the first distance difference D2 and a distribution of the second distance difference D3 with respect to a plurality of samples of the reproduction signal;

a fourth arithmetic section configured to determine a mean value M2 of the first distance difference D2 and a mean value M3 of the second distance difference D3;

a fifth arithmetic section configured to determine a recording compensation parameter Ec from a relationship of (M2−

M3)/2; and

a conversion section configured to convert the recording compensation parameter Ec to a recording compensation parameter Ec′

on the basis of frequency-of-occurrence information on various patterns determined based on properties of modulation codes;

finding a compensation amount WC based on the recording compensation parameter Ec′

; and

a compensation section configured to compensate a signal recording waveform for the information recording medium based on the compensation amount WC,

wherein said first pattern includes a code bit train “

10”

or “

01”

,

said second pattern is a pattern having the same number of bits as the first pattern, the second pattern including “

11”

corresponding to the code bit train “

10”

or “

01”

of the first pattern, and

said third pattern is a pattern having the same number of bits as the first pattern, the third pattern including “

00”

corresponding to the code bit train “

10”

or “

01”

of the first pattern.