| 摘要 |
<p>PURPOSE:To realize tracking control with high accuracy by using a drop out pulse outputted in the case of not tracing a video tape correctly by a video head. CONSTITUTION:When the video head A comes off a best tracking position, a pulse P is sent from a drop out pulse detector to a differentiation circuit 3. The pulse P is differentiated at the circuit 3, and is supplied to an envelope generation circuit 4. An envelope voltage is sent to a comparator 5, and is compared with a reference voltage V. The reference voltage is set at a level not to drive a driving motor 8. A differential voltage V0 is outputted from the comparator 5 to a voltage controlled oscillator 6, and a control voltage V1 to set the differential voltage V0 at 0 is generated, and is supplied to a tape driving motor controller 7. Here, a control signal S is generated, and it is supplied to the driving motor 8, and tape speed is controlled, thereby, the head A is introduced to a position traceable on a track correctly.</p> |
