Patent ID: 7317766
Filing Date: 2008-01-08
Classification: G11B,H03M

Abstract:
1. A signal demodulation apparatus which demodulates a code that is modulated from an N-bit data word into an M-bit codeword, comprising: a reliability detection unit which receives data indicating probability values of the code, and after forming the probability values into a unit having a predetermined length L, compares an absolute value of each probability value forming the one unit with a predetermined reference value, and outputs location information and sign information of the probability data values forming the one unit that have an absolute value greater than the predetermined reference value; a sign comparison unit which compares the location and sign information with corresponding location and sign information of respective ones of a plurality of codewords stored in advance and outputs the codewords in which the location and sign information of the respective codeword are the same as the location and sign information output by the reliability detection unit; and a data word probability value calculation unit which calculates a value indicating the probability of a bit for each bit forming the data word based on the codewords output by the sign comparison unit and the data indicating the probability values of the code.