| 摘要 |
PURPOSE:To read address information without any influence of a dropout by synchronizing the rotational frequency and phase of a disk with a reference signal and by using clock pulses generated from the reference signal. CONSTITUTION:The rotational frequency of a disk 1 is detected by a rotary encoder 6 fitted on the rotary shaft of a motor to synchronize a horizontal and a vertical synchronizing signal with the rotation state of the motor. When the starting part and ending part of each vertical blanking period are as shown by 51 and 52, the blanking periods are hatched parts. Since the synchronizing signals are synchronized completely with the rotation state of the motor, the starting point and ending point of the vertical blanking period of each information track are completely coincident in a disk radius direction. In addition to the vertical synchronizing signal, the horizontal synchronizing signal is also coincident in the disk radius direction. |
