| 摘要 |
PURPOSE:To expand a range where a magnetic head is led onto the target track, by forming plural position signals from two-phase servo-information from the servo- head, and selecting a position signal in accordance with a command signal of the target track. CONSTITUTION:The servo-information detection part 60 generates signals A-D which are periodically varied in accodance with the position of the servo-head 20, generates position signals E-H which are out of phase by 90 deg. each in accordance with said signals A-D, and sends them out to the selective part 70. In case when a signal EVEN becomes high and the target track is an odd track, the selective part 70 selects and outputs one of the signals F, H in accordance with the polarity of the signal E or G, and also in case when the signal EVEN becomes low and the target track is an even track, the selective part 70 selects and outputs one of the signals E, G in accordance with the polarity of the signal F or H. The range where leading-in can be made is expanded by using this output position signal M. |
