Code modulator and code modulation method
AssigneeInternational Business Machine Corporation
InventorTeruhiko Ushio
Life of this patent
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Abstract
A method and apparatus are provided for modulating code for use with written optical disks such as digital video disks (DVD). The invention falitates {fraction (8/16 )} modulation by eliminating duplicate code conversion and by reducing the number of times that conversion codes must be looked up from a conversion table. A conversion code corresponding to a received input code is specified from among a plurality of conversion codes. Duplication information corresponding to the input code is read from a pre-processing table and duplicate information indicated duplicate conversion codes in the plurality of conversion codes is stored. Conversion code corresponding to the input code is read from the conversion table and is selectively stored with duplicate conversion codes being ommited.
Claims17
A code modulator for converting an input code to one of a plurality of conversion codes, comprising:
- a conversion table for storing conversion codes corresponding to input codes with duplicate conversion codes being omitted from said plurality of conversion codes;
- a pre-processing table for storing duplication information indicating a correspondence relationship between the conversion codes omitted from said plurality of conversion codes and the same conversion codes in the conversion table as the omitted conversion codes;
- code specifying means for specifying a conversion code to be used from said plurality of conversion codes;
- and
- code conversion means for reading a conversion code corresponding to an input code from said conversion table on the basis of the specification done by said code specifying means and the duplication information stored in the pre-processing table.
A code modulation method for converting an input code to one of a plurality of conversion codes, comprising:
- a code specifying step of specifying a conversion code to be used from a plurality of conversion codes corresponding to an input code;
- a step of reading duplication information corresponding to the input code from a pre-procssing table in which the duplication information indicating duplicate conversion codes in the plurality of conversion codes is stored;
- and
- a code conversion step of reading a conversion code corresponding to the input code from the conversion table which stores conversion codes with duplicate codes being omitted on the basis of the specification of the code specifying step and the duplication information read from the pre-procesing table.
Dependencies are inferred from the claim text.