Patent ID: 7006018

Claim:
A coding program for converting an m-bit information word continuously into an n-bit code word, the program comprising the steps of: generating a first information sequence by inserting a first DC control bit into an input information sequence at predetermined intervals and generating a second information sequence by inserting a second DC control bit different from the first DC control bit into the input information sequence at the predetermined intervals; generating a first provisional code sequence by making a code conversion of the first information sequence generated in the information sequence generating step at a conversion ratio of an information word length m to an code word length n; generating a second provisional code sequence by making a code conversion of the second information sequence generated in the information sequence generating step at the conversion ratio of the information word length m to the code word length n; and delaying the first provisional code sequence and producing a delayed first provisional code seguence; delaying the second provisional code sequence and producing a delayed second provisional code sequence; and selecting either the delayed first provisional code sequence generated in the first code generating step or the delayed second provisional code sequence generated in the second code generating step, wherein the first and second code converting steps uses a coding rule by which, in case the coding rule is represented by a finite-state code conversion table, code words are assigned to information words so that a two's complement of a sum of coding bits included in the first provisional code sequence is always different from a two's complement of a sum of coding bits included in the second provisional code sequence when a first code state of the first provisional code sequence encoded starting with a predetermined original state, is identical to a second code state of the second provisional code sequence encoded starting with the predetermined original state.