Patent ID: 8531932

Claim:
An optical disc device having a function of recording data into an optical disc medium by using codes whose shortest run length is 2T and a function of reproducing the recorded data in accordance with an adaptive equalizing procedure and a Partial Response Maximum Likelihood (PRML) procedure, comprising a circuit configured to generate a first binary bit array by binarizing a signal reproduced from the optical disc medium in accordance with the PRML procedure; a circuit configured to generate a second binary bit array and a third binary bit array whose shortest run length is equal to or greater than 2T, and which are obtained by shifting an interested edge of the first binary bit array to the left and right, respectively; circuits configured to generate first, second and third target signals corresponding to the first, second and third binary bit arrays, respectively; a circuit configured to calculate a first evaluation value by normalizing a first Euclidean distance difference which is a difference between the Euclidean distance between the second target signal and the reproduced signal and the Euclidean distance between the first target signal and the reproduced signal, by the Euclidean distance between the first and the second target signals; a circuit configured to calculate a second evaluation value by normalizing a second Euclidean distance difference which is a difference between the Euclidean distance between the third target signal and the reproduced signal and the Euclidean distance between the first target signal and the reproduced signal, by the Euclidean distance between the first and the third target signals; and a circuit configured to adjust a condition for recording data into the optical disc medium by using at least a value of difference between the first and the second evaluation values; wherein the second and the third bit array are generated by applying an exclusive OR (XOR) mask bit array to the first binary bit array so that a first Hamming distance between the first binary bit array and the second bit array is equal to a second Hamming distance between the first binary bit array and the third bit array, the first and second Hamming distance being greater than or equal to 2.