| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic disk unit in which an increase of convergence time is suppressed and desired performance can be exhibited regardless of setting of an initial value. SOLUTION: A circuit to control the position of a magnetic head 5 is a frequency estimator which estimates the frequency of an error signal. The magnetic disk unit includes the frequency estimator which sets an initial value for the beginning, and controls the update value of the frequency to be estimated in such a manner that the convergence rate of the frequency to be estimated with respect to the signal frequency to be removed is constant regardless of the difference between the initial value and the frequency of the signal to be removed included in the error signal, and a disturbance remover which generates and outputs a signal in reverse phase to the signal of the frequency component included in the error signal and estimated by the frequency estimator. COPYRIGHT: (C)2008,JPO&INPIT
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