| 摘要 |
PROBLEM TO BE SOLVED: To obtain a highly accurate learning value regarding a synchronous vibration estimated value even when averaging for a position error signal is reduced. SOLUTION: Averaging is carried out by an averaging section 52 for a position error signal (PES) indicating a relative position between position information (RRO) prerecorded in a magnetic disk 12 and a magnetic head 20, an operation amount is obtained by a phase compensator 46 based on the PES, averaging is carried out for this operation amount by an averaging section 50, signals processed by the averaging sections 50, 52 are subjected to convolution integration by using transmission characteristics which are obtained by adding 1 to loop transmission characteristics decided by the model P0 of a magnetic head actuator and a servo control circuit in order to obtain a synchronous vibration estimated value, this synchronous vibration estimated value is subjected to high pass-filter processing having zero phase error characteristics by a filter processing section 58 to remove the vibration component of a low frequency band, and thus a highly accurate synchronous vibration learning value is obtained.
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