Patent ID: 8130618
Filing Date: 2012-03-06
Classification: G11B

Abstract:
1. A method for operating log likelihood ratios output by a soft-decision most-likelihood decoder in a disk apparatus to which iterative decoding is applied, the method comprising: setting a first window and a second window for a sequence of the log likelihood ratios output by the soft-decision most-likelihood decoder based on the sequence of the log likelihood ratios or an amplitude of a read signal acquired by a head configured to read data from a data sector on a disk, wherein the first window corresponds to a defective portion on the data sector and the second window corresponds to a normal portion on the data sector; multiplying the log likelihood ratios in the first window by a first multiplier and multiplying the log likelihood ratios in the second window by a second multiplier if the defective portion on the data sector is detected, wherein the first multiplier is greater than 1 and the second multiplier is less than 1; and transmitting the sequence of the multiplied log likelihood ratios to a parity check decoder.