| 摘要 |
PURPOSE:To reduce a noise due to an inhomogeneous medium of a disk and to obtain a high quality position signal by storing a variation amount of each cylinder in an analog signal and canceling a partial amplitude fluctuation. CONSTITUTION:A bit of servo information read out by a head 10 is detected via an amplifier 11 by a demodulator 12 into a position signal 13, which is then inputted into an adder 14. On the other hand, when an output of an address register 15 selects an address of a memory 9, a bit of information read out of the memory 9 is analogized by a D/A converter 16, where a position signal of a servo information write device corresponding to each cylinder is regenerated into an analog signal 17. When a reversed polarity position signal 18 as the result of reversing the analog signal 17 in its polarity is inputted into one side of the adder 14 to be added to the position signal 13, a corrected position signal 19 is then outputted by canceling a noise part on the disk surface. By this method, a high quality position signal can thus be obtained.
|
