| 摘要 |
PROBLEM TO BE SOLVED: To provide an offset-adjusting circuit, in which the influence of asymmetry is reduced and in which the error rate of reproduced data can be reduced by a method where the offset of a reproduced signal is removed, when the signal of an optical disk is reproduced and an offset which is generated due to the asymmetry is corrected and to provide a reader which uses the offset- adjusting circuit. SOLUTION: In this reader, the DC component of a reproduced signal Sin from an optical pickup is removed by a capacitor 20, and a signal SA which contains only an AC component is obtained. By a peak hold circuit 30 and a bottom hold circuit 40, a peak value P and a bottom value B of the signal SA are found respectively. Based on these values, an offset-adjusting value (P+B)×k is calculated. A signal SL as an offset-adjusting signal, in which a high-frequency component contained in the value is attenuated, is added to the signal SA. Thereby, the offset of the reproduced signal Sin is adjusted, and the influence due to asymmetry can be suppressed.
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