| 摘要 |
PROBLEM TO BE SOLVED: To obtain a magnetic disk apparatus in which a head can be positioned with good accuracy in an arbitrary position in the radial direction on a disk by measuring the gain of a positioning control system with respect to the position of the head to find the relationship between the position of the head, and converting a position signal and an observed position signal into the precise position of the head. SOLUTION: A target position 37 is made to offset by every set value. A head is positioned in a measuring place inside a track pitch. In this position, an excitation signal 65 at a certain frequency is applied from a positioning-control-system open-real- gain measuring part 62, and the head is excited. Then, signals before and after the excitation signal is applied are measured. The amplitude ratio of the excitation frequency component of a measuring signal (1) 66 to the excitation frequency component of a measuring signal (2) 67 is calculated. After that, a prescribed parameter is decided in a position-signal nonlinear-amount-parameter decision part 63. By these processing operations, the relationship between the position of the head and a position signal is obtained, and the relationship can be converted into the precise position of the head.
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