| 摘要 |
PURPOSE:To perform track seek at high speed, by adding a micro feed circuit on a stepping motor, and providing a second component sine wave digital filter in a feedback loop in a track following mode. CONSTITUTION:The micro feed circuit is constituted of read only memories ROM 13 and 13' which output exciting currents d1 and d1' to each phase corresponding to the balancing point position (u) of a two-phase linear stepping motor SM, and amplifiers 16 and 16' which impress a driving current on the SM. By using the said circuit, it is possible to set the balancing point position (u) of the SM arbitrarily in spite of a pitch decided by the mechanical structure of the SM< and to realize the following characteristic of a head with high accuracy by the combination of a digital controller. The second component sine wave digital filter 11 makes a magnetic head follow a targeted track stationarily with a position error of zero, and a stabilizing digital filter 12 stabilizes the feedback loop of the track following mode. In such a way, it is possible to accelerate the track seek.
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