| 摘要 |
<p>PROBLEM TO BE SOLVED: To compensate an additional signal in a data signal by detecting the time when a compensated data signal exceeds a predetermined threshold, and varying a setting level of a direct-current offset according to it. SOLUTION: In an ordinary mode, a compensator 113 detects the existence of TA signal (exceeds a predetermined threshold) in a TA influence signal 114, and starts thermal asperity mode. The compensator 113 evaluates the amplitude of TA signal component in the TA influence signal, and it gives an initial direct-current voltage level offset as a compensation signal 115. During the term in TA mode, the compensator 113 gradually decreases the compensation signal 115 to zero value as the TA signal (and TA influence signal 114) decreases. Therefore, a compensated signal 118 is maintained in an operation range of ADC 108. During the term in TA mode, the compensator 113 also holds a gain timing control loop 107 by using the gain timing control signal 116.</p> |
