| 摘要 |
<p>PURPOSE:To facilitate control over the absorption of longitudinal vibration of a tape and to apply the best DC tension to the tape simultaneously with and independently of the said control, by detecting the tape tension. CONSTITUTION:The output signal 53 of a tape tension detector TD using, for example, an optical slit plate is amplified 32 and then supplied to a differentiating circuit 33 and a low-pass filter 36. The output of the differentiating circuit 33 is compared with a reference voltage 35 and amplified by a differential amplifier 34 and then drives a tape vibration damping device DA which uses, for example, a voice coil. Since the output of the differentiating circuit 33 shows a speed variation component due to the vibration of a tape T, the tape vibration damping device DA damps the vibration of the running tape T excellently. An output signal from a low-pass filter 36 is compared with a reference voltage 38 and amplified by a differential amplifier 37 and then supplied to a motor 39 which drives a feed reel to vary torque, controlling the tension of the tape T.</p> |
