Patent ID: 6989775

Claim:
A recording medium having recorded therein a coding program to cause a computer to convert 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 same predetermined intervals as in the first information sequence; 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; delaying the first provisional code sequence and producing a delayed first provisional code sequence; delaying the second provisional code sequence and producing a delayed second provisional code sequence; and selecting either the first provisional code sequence generated in the first code generating step or the second provisional code sequence generated in the second code generating step, wherein the first and second code converting steps use a coding rule represented by a finite-state code conversion table in which 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.