Patent ID: 7196999
Filing Date: 2007-03-27
Classification: G11B,H03M

Abstract:
1. A data reproducing apparatus for reproducing data recorded by a recording equipment for recording data on a recording medium, the recording equipment including modulation encoding means for applying predetermined modulation encoding to input data, the input data having a bit sequence, wherein said modulation encoding means encodes the input data in accordance with a constraint condition by block modulation, and first interleaving means for interleaving data supplied from said modulation encoding means for re-arraying a data sequence corresponding to said data supplied from said modulation encoding means, said data reproduction apparatus comprising: deinterleaving means for deinterleaving reproduced data in a sequence such as to restore the data sequence to the bit sequence; modulation decoding means for modulation decoding data supplied from said deinterleaving means in conformance with said constraint condition, wherein said modulation decoding means includes likelihood calculating means for calculating a likelihood value corresponding to output codewords output by said modulation encoding means, wherein posterior probability information as a soft decision value for an input bit to said modulation encoding means and an output bit from said modulation encoding means is calculated using said likelihood value as calculated by said likelihood calculating means; and second interleaving means for interleaving difference data corresponding to a difference between data output by said modulation decoding means and data output by said deinterleaving means, based on the same interleaving position information as that of said first interleaving means, for re-arraying the sequence of the difference data.