| 摘要 |
PURPOSE:To decrease greatly the data error rate of a magnetic disk device by providing a response switching means which switches response characteristics of a low-pass filter according to a specified cylinder group to which a track whose read signal is read belongs. CONSTITUTION:When an input signal is supplied to a phase detection part 1 through a connection line 11, the phase difference between said input signal and a signal supplied from a voltage-controlled oscillator 3 through a connection line 18 is detected by a phase detection part 1 and a voltage corresponding to the difference is supplied to the low-pass filter 2 through a connection line 16. Whether a track where data to be read is recorded is inside or outside of a predetermined track is detected; and the band of the low-pass filter 2 is narrowed down when the track is inside or widened when outside to allow a phase synchronizing circuit to have response characteristics suitable for a read of respective data, reducing the error rate of the data read. |
