| 摘要 |
<p>A tape running time indicator comprises means for generating a predetermined number of pulse signals every turn of the reel; means for determining the rotational period of said reel from said pulse signals during the constant-speed operation; means for calculating the number of reel pulses that corresponds to the length of the tape wound on the reel, the calculation based upon the rotational period, the diameter of the reel hub, the tape speed and the tape thickness; means for counting up or counting down, depending upon the rotational direction of the reel, the number of pulses produced accompanying the rotation of the reel, means for calculating the tape running time by converting the number of tape pulses into a constant-speed running time when a signal for indicating the tape running time is input; and means for indicating the thus calculated tape running time.</p> |
