Method of converting bits of optical disk, demodulating method and apparatus

摘要

A method and apparatus are described which demodulate channel bits modulated by an arbitrary one of two modulation schemes, by making use of a consolidated reference table with a small address space. The method of the invention comprises the steps of: generating first output bits for representing patterns that correspond to patterns represented by first channel bits other than those patterns being unable to exist under first RLL constraints, the first output bits having a lesser number of bits than the first channel bits; and generating second output bits for representing patterns that correspond to patterns represented by second channel bits other than those patterns being unable to exist under second RLL constraints, the patterns represented by the second output bits being located at discontinuous areas of the patterns represented by the first output bits, the second output bits having a lesser number of bits than the second channel bits. The first and second output bits are used for designating an address of a demodulating reference table.