| 摘要 |
<p>PURPOSE: To highly accurately control tracking in a short time by changing a target tracking value continuously at high speeds and obtaining the target value in a step wherein a reproduced output of a rotary head is changed from an increase to a decrease and from a decrease to an increase. CONSTITUTION: A tracking value generator 5 increments and generates a tracking value per one rotation of a head drum 1 by a pulse of a drum servo circuit 8 which is synchronized with the rotation of the head drum, and supplies the value as a target value to a servo circuit 7 thereby to control a capstan motor 12. At this time, a neural network 4 detects maximum and minimum points of an output of a video head 9 from an envelope detector 2, reversing a changing direction of the tracking value generator 5 at the maximum point. Then, the neural network 4 changes at the minimum point the output by a count of steps so that an operated output becomes maximum, thereby making the output agree with the target value. Accordingly, the maximum point can be detected quickly and a correct correction is executed to a change with time.</p> |
