| 摘要 |
<p>PURPOSE:To make the tape tension constant at all times by detecting a difference of drive currents of each driving motor of a double capstan and giving a detected output to a speed servo circuit of the drive motor at the tape supply side so as to keep the peripheral speed difference of both capstans constant. CONSTITUTION:A frequency generator is fitted to a rotary shaft of the capstan motors 4, 5, a capstan rotating speed is detected by an output EG, and the generator is provided to each motor of speed servo loops 6, 7 controlling a motor drive voltage in response to an error with the reference value. Further, the capstan motor control circuit is provided with a phase servo loop 18. Moreover, the motor control circuit is provided with a detecting circuit 22 detecting the difference of drive currents of both capstan motors 4, 5. An output of the detecting circuit of the difference of drive currents is fed back negative to an S side motor 5 similarly as the speed servo loop 7 and then, the control making the tape tension constant is attained.</p> |
