| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic disk device in which noise is reduced and which is further excellent in control characteristics of an actuator by speed electromotive force. SOLUTION: A digital/analog converter supplies control voltage Vdac constituted of a first setting voltage value V1, a second setting voltage value V3 and a transition voltage value V2 of substantial cosine wave which connects the first setting voltage value and the second setting voltage value, to a VCM driver. Drive current is supplied from the VCM driver to a voice coil of an actuator assembly. Since current including no higher harmonic component flows to VCM current Ivcm which flows in the voice coil in a transition period P2, vibration force is easily controlled by shifting a resonance point on structure including the actuator assembly. In addition, since counter-electromotive force VL generated in inductance becomes zero in a period of half-wavelength of the cosine wave, the speed electromotive force is measured by quickly transiting from a setting period to a measurement period. COPYRIGHT: (C)2008,JPO&INPIT
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