| 摘要 |
PROBLEM TO BE SOLVED: To prevent an error in a reading operation to be caused by a speed variation in a writing operation. SOLUTION: A servo head 1 reads out a servo signal that is being written continuously or intermittently on a medium. A servo signal detection circuit 2 converts the servo signal into pulses and supplies them to a write clock phase comparison circuit 5. The write clock phase comparison circuit 5 compares a phase of the servo pulse signal with a phase of a write clock to be generated by a write VCO 6, and applies a difference between the two phases to the write VCO 6 as a control voltage CV. The write VCO 6 generates the write clock in accordance with the control voltage CV. A data synchronization circuit 7 allows write data to be synchronized with the write clock and supplies the data to a write driver 8. The write driver 8 applies a writing current based on the synchronized write data to a write head.
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