| 摘要 |
<p>PURPOSE:To perform high-precision tracking control by adding a synchronizing and a discrimination signal to form into one block and controlling the tracking phase of a reproducing head on the basis of the compared output between the discrimination signal detected in a playback signal and a reference discrimination signal. CONSTITUTION:Track discrimination signals TRID11-TRID42 separated from the playback signal and a state decision signal STSi are supplied to a tracking control circuit 2. The signal STSi is 1 when a block synchronizing signal is extracted or 1 when not. The control circuit 2 detects a tracking state and generates a control voltage. A monostable multivibrator MM4 is supplied with a servo reference signal from a terminal 5. A reproduced control pulse of a fixed head is supplied to a terminal 10. A sample holding circuit 9 constitutes a phase comparing circuit and outputs a voltage corresponding to the phase difference between the servo reference signal and control pulse to control a VOC (voltage- controlled oscillation circuit) 12. Pulses from a speed control pulse generating circuit 13 are supplied to a capstan motor 14 while its period is controlled by the frequency of the output of the VCO12.</p> |
