| 摘要 |
<p>PURPOSE: To perform the tracking of the head on the best picture quality point by controlling the rotational phase of the motor by varying the phase control elements of the phase control system so as to minimize the level of the high-frequency component of the extracted jitter. CONSTITUTION: The speed detection section 2 detects the digital speed value from the speed signal proportional to the rotational speed of the motor 1 generated by the frequency dynamo (not shown in the figure) attached to the capstan motor 1 and feeds the speed value to the subtraction section 3. The subtraction section 3 subtracts the target value fed from the speed target value generated section 4 from the present inputted speed value of the motor 1 to calculate the speed error of the motor 1 and to output to the subtraction section 5. The subtraction section 5 subtracts the speed error from the phase error inputted from the subtraction section 13 to generate a control error signal and output to the compensation filter 6. After compensating for the high-frequency level of the inputted signals, the compensation filter 6 lets them pass through the low-pass filter 8. The signals converted to analogue ones are outputted to the motor drive circuit 9, which rotates the motor 1 to the inputted analog control error signals to be inputted.</p> |
