| 摘要 |
<p>PURPOSE:To ensure the control of a tape at a constant speed with a driving motor, by reading the pulse signal of a certain frequency and recorded on the tape in the form of a speed signal of tape shift and then controlling the number of revolutions of the driving motor. CONSTITUTION:The pulse of a certain frequency is recorded at a side of a tape. This tape is taken up by a driving motor 3, and the recorded pulse is read by a pulse reading head 2. This read signal is amplified, and the number of pulses is detected in the form of the frequency by a pulse number discriminating circuit 5 to be compared with a pulse frequency 7 of a constant speed by a differentiating device 6. Then this increase or decrease is detected in the form of the voltage. This detected voltage is supplied to a driving motor controller 9 as the control source of a driving power source 8 of the motor 3. Thus the number of revolutions of the motor 3 is controlled to always obtain a certain value for the take-up speed of tape. As a result, a constant-speed driving motor can be eliminated, and accordingly the motor 3 is controlled to always ensure a certain take-up speed of tape regardless of the variation of the tape take-up diameter.</p> |
