Patent ID: 8239742

Claim:
An encoding apparatus for carrying out an encoding process by combining two different code words, an RLL (Run Length Limited) code word and an error correction code word, with an interleaving technique, said encoding apparatus comprising: error correction encoding means for encoding input data into said error correction code word; interleaving means for interleaving (k×m) said error correction code words each having a length of n symbols in the case of said RLL code word composed of an information word with a length of m symbols where a symbol is a unit composing said error correction code word, notation m denotes an integer equal to or greater than 2, that is, m≧2, and notation k denotes an integer equal to or greater than 1, that is, k≧1; and RLL encoding means for encoding an information word of an RLL code word, which is generated by said interleaving means, into said RLL code word, wherein, if an address i, where notation i is an integer satisfying relations 0≦i<k×m, is assigned to each symbol of said k×m error correction code words and x ij is taken as a notation denoting the number of symbols included in n symbols of a jth, where notation j is an integer satisfying relations 0≦j<m, code word of m error correction code words to serve as symbols corresponding to said address i of an information word of an RLL code, for any j, said interleaving means interleaves a series inside an information word of said RLL code word so that the following relations are satisfied: ∑ i ⁢ x ij = n ⁢ ⁢ and ⁢ ⁢ x ij > 0.