| 摘要 |
PURPOSE:To accomplish high track density using a simple constitution by calculating the positional and directional deviations based on a detection signal for a positional information pattern on a disk plate and by detecting the positional deviation of track according to a closed control method. CONSTITUTION:A positional information pattern on a disk plate 1 is read out by a read/write head 3, the high frequency component of a signal (a) which was amplified by a read amplifier 4 is removed by a detection rectification circuit 5, the signal (b) which is half-wave rectified is delayed by 5-10 microseconds in a delay circuit 6, and amplified at an amplification ratio of 0.95 by an amplifier 7, thus producing a signal (c). Signals (b) and (c) are compared by a comparator a and a signal (d) raising at the neighborhood of a peak point is generated. A pulse conversion circuit 9 produces the signal (e) which is set at level H at the first rise of the signal (d) and at level L at the second rise of signal (d). A control circuit 10 measures the pulse width of signal (e) and compared with on-track pulse width T0, an the positional and directional deviations of the read/write head are calculated. |
