Claims
- 1. An optical disk apparatus, comprising:
- reproducing means for binary-coding analog information supplied from an optical disk with a predetermined slice level so as to reproduce the analog information:
- slice level changing means for providing a plurality of offset values to the predetermined slice level when a specific data pattern of the optical disk is reproduced so as to change the slice level;
- error number calculating means for calculating the number of errors in reproduced data occurring with respective slice levels;
- slice level correcting means for determining an offset value for obtaining an appropriate slice level which will lower the number of errors to below a predetermined value for the optical disk of a specific type; and
- margin reducing means for reducing the size of a margin between an upper limit and a lower limit of a slice level by changing the reproducing conditions if the margin is larger than a predetermined value so as to keep the number of errors within an allowable range.
- 2. An optical disk apparatus according to claim 1, wherein the appropriate slice level is a level which is intermediate between the upper limit and the lower limit of a slice level with which the number of errors is made to be smaller than an allowable value.
- 3. An optical disk apparatus according to claim 1, wherein the appropriate slice level is a slice level with which the number of errors is made to be smallest.
- 4. An optical disk apparatus, comprising:
- writing means for writing a specific data pattern on a predetermined region of an optical disk;
- binary-coding means for binary-coding a reproduced analog signal of the specific data pattern with a plurality of slice levels;
- calculating means for calculating the number of errors in reproduced data occuring with respective slice levels;
- determining means for determining an appropriate slice level for the optical disk in accordance with the calculated number of errors which will lower the number of errors to below a predetermined value; and
- margin reducing means for reducing the size of a margin between an upper limit and a lower limit of a slice level by changing the reproducing conditions if the margin is larger than a predetermined value so as to keep the number of errors within an allowable range.
- 5. An optical disk apparatus according to claim 4, further comprising
- means for setting the plural slice levels by providing a plurality of offset values for a predetermined slice level.
Parent Case Info
This is a divisional, of application Ser. No. 08/745,425, filed Nov. 12, 1996 now U.S. Pat. No. 5,777,964.
US Referenced Citations (9)
Foreign Referenced Citations (7)
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JPX |
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Divisions (1)
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Number |
Date |
Country |
Parent |
745425 |
Nov 1996 |
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