INFORMATION RECORDING AND REPRODUCING DEVICE AND METHOD AS WELL AS SIGNAL DECODING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To improve decoding performance by efficiently incorporating the characteristics of a noise model formed by exactly modeling the noise characteristic of magnetic recording and reproducing channels into a decoding process. SOLUTION: The correlation of the noises to the past and future states dependent upon the input signal patterns in the past N bit and future Q bit and the dispersion thereof are calculated and stored in a noise correlation computing section 84 by training in maximum a posteriori probability (MAP) decoding. In reproducing the whitening noise values for the past and future states obtained by whitening the chromatic noises by using the correlation of the noises and the dispersion thereof stored by a whitening noise computing section 91 and the input signal (channel information)ΛC (yk|s k ) of the maximum a posteriori probability decoding is calculated from the whitened noise values for the past and future states by an image signal computing section 92 and the likelihood in the maximum a posteriori probability decoding (MAP decoding) is determined from this input signal.