| 摘要 |
<p>PURPOSE:To set the tape speed at a fixed level in a fast forward mode by detecting the revolving cycles of both the take-up and supply reels of a magnetic tape and then controlling the drive torque of a motor which drives the take-up reel based on the detected revolving cycle. CONSTITUTION:The right and left reel revolving cycles are referred to as Tt and Ts respectively, and the values of Tt, Ts and Tt<2>+Ts<2> are shown in a graph. As a result, the value of Tt<2>+Ts<2> is constant at any position of a tape as long as the tape speed is constant. On the contrary, the tape speed can be controlled to an optional fixed level when the value of Tt<2>+Ts<2> is set at an optional fixed level. Here the tape speed is controlled so that the value of Tt<2> is equal to 1/900 compared with that of a reproduction mode. Then the tape speed can be controlled at a fixed level equal to 30 times as high as that of a reproduction mode when the tape is fast forwarded. Then it is discriminated whether the tape speed is higher or lower than the level equal to 30 times as high as that of the reproduction mode. When the tape speed is lower than said level, the revolving cycle of a reel drive disk is increased. Therefore the value of Tt<2>+ Ts<2> is larger than the comparison data C. Thus the driving torque of a reel motor is increased to increase the tape speed.</p> |
