| 摘要 |
PURPOSE:To improve the performance of a servo system by producing a position error signal after a servo pattern is detected by a preceding erasion gap. CONSTITUTION:A physical distance L exists in a gap between an erasion head 12 and a recording/reproducing head 13. Therefore, the track position error signal detected by the head 12 also indicates a track shift produced to the head 13 after a time T equivalent to the distance L. In other words, a servo pattern is detected by the head 13 for acquisition of the track position error signal. Based on this error signal, the calculation needed for the voltage which drives an actuator in advance. As a result, the stability of a servo system is improved, therefore the checking result is obtained with extremely good tracking characteristics.
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