| 摘要 |
PURPOSE:To realize a constant-speed travelling of a tape in both the forward and backward directions, by switching the driving voltage of two pairs of the reel driving DC motors in accordance with the selection mode and at the same time giving a control to the driving voltage via a servo system that is shared in both the forward and backward directions. CONSTITUTION:When the fast forwarding switch 50 is closed, the FF54 is set to make the transistor Q3 of the switch control circuit 61 conduct. Then the 1st and 3rd switches S1 and S3 are turned on with the 2nd and 4th switches S2 and S4 turned off respectively. Thus the driving voltage is switched, and the 1st and 2nd DC reel motors 3 and 4 are set at the supply side and the take-up side respectively to give a fast forwarding to the tape 7. At the same time, the driving voltage of the motors 3 and 4 receive a servo control via the tape tension detector 26 that is shared in both the forward and backward directions of tape travelling and the tape traveling speed detector 37. As a result, the tape 7 is forwarded quickly. The same procedure is effective also in other modes. In such way, a tape is forwarded in both the forward and backward directions and in a constant speed through a simple constitution. |
