(A) ;ENCLOSED TRANSMISSION DEVICE

摘要

PURPOSE:To control the tape stop position with high accuracy by obtaining the angular speed and the revolving angle of a capstant motor by a microprocessor from the intervals of the output signals and the number of this signals of a revolution detector and performing a track calculation to stop a tape after a shift of a prescribed amount. CONSTITUTION:When a capstan motor 11 starts its revolution, a detection pulse FG is produced from a revolution detector 12. A control circuit measures the revolving angle and the angular speed of the motor 11 from the counted number of pulses FG and the interval of the pulse FG respectively. Based on the results of these measurements, a microprocessor of the circuit 15 applies the brakes. Thus a magnetic tape is sent accurately by a distance L1 equivalent to a frame. Then the circuit 15 produces a control pulse DP having such pulse width tauX that stops the drive of the tape after a shift of the distance L1. This reduces the torque ripple of the motor 11 or the effect of a secular change. Thus the tape shift amount can be controlled with high accuracy.