PURPOSE: To simply adjust a position where an index signal is generated and to make the adjustment accurate by retarding the generating timing of the index signal in response to the timing of a burst signal and setting the generating time difference within a prescribed range.
CONSTITUTION: An index signal generated by an index detector 4 becomes an index signal on the front side retarded by a preset time via a front side variable delay circuit 17a. On the other hand, the index signal becomes an index signal on the rear side retarded by a preset time via a rear side variable delay circuit 17b. As a result, it is possible to make the time difference between the leading of the retarded index signal on the front side and the generating timing of the burst signal on the front side and the time difference between the leading of the retarded index signal on the rear side and the generating timing of the burst signal on the rear side within a prescribed range respectively and a magnetic head is surely located in a preamble of a tack of a flexible disk at the leading of the retarded index signal.
SATO TADASHI
KITAZAWA HIRONORI
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