METHOD FOR ADJUSTING RECORDING CONDITION, OPTICAL DISK DEVICE, AND METHOD FOR RECORDING INFORMATION

摘要

PROBLEM TO BE SOLVED: To provide a method for efficiently evaluating a playback signal with high reliability and an optical disk device using the method so as to solve the problem in which a circuit scale is exponentially increased in response to an increase in a constraint length of a PRML system in the case that coincidence between a binary bit string and a predetermined evaluation bit string is determined in order to evaluate the quality of a playback signal to calculate Euclidean distance in a large-capacity optical disk system whose constraint length is 5 or more.

SOLUTION: An evaluation bit string is assumed with a continuous number of 2T included in a predetermined evaluation bit string as i by dividing the evaluation bit string into a main bit string of the length of (5+2i) and a sub bit string of both sides. Determination processing as to whether the predetermined evaluation bit string is included in a binarized bit string is aggregated by coincidence determination of the main bit string. This prevents an increase in a circuit scale. The scale of an evaluation accumulation circuit can be reduced at the same time by separately calculating a Euclidean distance between a playback signal and a target signal corresponding to an evaluation bit string in each main bit string and accumulating the result.

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