| 摘要 |
PROBLEM TO BE SOLVED: To obtain an accurate demodulated moving velocity by correcting the overflow of the demodulated moving speed of a head caused by fast seek of the head. SOLUTION: A magnetic disk device 300 includes a position and speed demodulating circuit 100. The position and speed demodulating circuit includes a difference calculating unit 105 which demodulates the moving speed of the magnetic head based on a phase difference in servo reproduction signals Even1 and Even 2 as servo data in the same sector; and an overflow detecting unit 108 which detects an overflow of the demodulated moving speed detected by the difference calculating unit 105 and calculates a correction value for the overflow. The overflow detected by the overflow detection unit 108 is corrected based on the correction value to output an accurate demodulated speed, so that the accurate demodulated moving speed is obtained even in the fast seek of the head. COPYRIGHT: (C)2008,JPO&INPIT
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