RECORDING CONDITION ADJUSTING METHOD, OPTICAL DISC DEVICE, REPRODUCING METHOD, AND INFORMATIONAL RECORDING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an efficient and reliable method for evaluating a reproduced signal in order to solve the problem in a large-capacity optical disc system with constraint length equal to or greater than 5 wherein when Euclidean distance is calculated by judging the coincidence between a binary bit array and a predetermined evaluation bit array in the evaluation of the quality of reproduced signal, the circuit scale exponentially increases with an increase in the constraint length of the PRML system, and to provide an optical disc device using the method.

SOLUTION: Assumption is made that the continuous 2T count included in a predetermined evaluation bit array is denoted by i and that each evaluation bit array is composed of a main bit array having a bit length of (5+2i) and auxiliary bit arrays on both sides. Determination processing on whether binary bit arrays include the predetermined evaluation bit array is concentrated on the match determination of the main bit arrays. This prevents increase in the circuit scale. At the same time, the Euclidean distance between the reproduced signal and the target signal corresponding to the evaluation bit array is calculated with respect to each main bit array and the results of such calculations are separated and counted. This reduces the scale of an evaluation and counting circuit.

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