| 摘要 |
<p>PURPOSE:To make a speed of revolutions constant (maximum) for a reel having a small quantity of tape winding, by discriminating the tape winding quantity in a tape fast forwarding mode for a tape fast forwarding control system of a magnetic tape device of a reel-to-reel system. CONSTITUTION:The difference is discriminated by a discriminating circuit 20 between the winding quantities R1 and R2 of reels 1 and 2. In the case of R1< R2, the circuit 20 gives an upward inclination to a switch 13. At the same time, a counter 13 counts the revolution information N of a driving motor 11A by the output signal of a tachometer 12A. A comparison arithmetic circuit 15 controls inertia calculating circuits 16A and 16B on the basis of the value (N-NO)/NO and then calculates a current value I1 so as to give the maximum speed of revolution of the motor 11A. Then the circuit 15 calculates the inertia current value I2 with which the revolution of a driving motor 11B can follow that of the motor 11A. The current values DELTAI1 and DELTAI2 corresponding to the tension and friction force of a tape are added to the current values I1 and I2 corresponding to the inertia to obtain the driving current values of the motors 11A and 11B.</p> |
