| 摘要 |
PROBLEM TO BE SOLVED: To improve a reproducing capacity by allowing a control means to select a detecting system of an offset detecting means capable of detecting an offset error by plural detecting systems to make a reproducing operation executable, so that the detecting system is changed according to the situation and an adequate offset error can be detected to perform proper processing. SOLUTION: A data signal recorded by an OP(optical pickup) 7 on a disk 6 by irradiating it with a laser beam is read by a magnetic head 5, and is outputted by being A/D-converted by an A/D converter 12. A Viterbi decoder 13 subjects this output data to Viterbi and necessary decoding processing to obtain a decoded data, and detects an offset error by plural detecting systems. A controller 2 feeds back this offset error to OP 7 via an LPC 4 and an APC 10, to cancel the offset. Thus, it is possible to eliminate an harmful effect of decoding error and perform excellent reproduction by selecting a detecting method of the Viterbi decoder 13.
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