| 摘要 |
PURPOSE:To improve the bit density and to simplify the control of a write frequency increasing the frequency of a write clock signal as the number of cylinders to which a head in placed becomes fewer (as the head is closer to the outermost circumference of a disk). CONSTITUTION:A register 1 records cylinder information representing the cylinder location via a system bus 20, and a filter/oscillator control circuit 2 outputs a control signal based on the cylinder information from the register 1. A filter circuit 6 changes stepwise the frequency characteristic of the filter based on a control signal from the circuit 2 and a control oscillator 9 outputs a write clock signal changed stepwise. That is, when the head is arranged to a location close to the outermost circumference of the disk 4, since the number of cylinders with a head placed becomes fewer, the frequency of the write clock signal is increased. Thus, the bit-density at all cylinder positions is made to a prescribed value and the storage capacity is increased.
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