| 摘要 |
<p>PURPOSE:To readily changeover tape speed at reproducing by adding the output of the level corresponding to the frequency of the reproduction control signal having been detected to a circuit having hysteresis characteristics and changing over swithes in accordance with the output of the circuit. CONSTITUTION:Since a recording start switch 13 is OFF at the reproducing, the signal of the level corresponding to the frequency of the control signal reproduced with a head 2 is inputted to a Schmitt trigger circuit 10 having hysteresis input- output characteristics by the monostable multi 8 of a frequency detecting means 7 which is not reset through an inverter 12 as well as an LPF 9. On the other hand, a NAND gate 16 is opened by the high output level of a NAND gate 11 by opening of the switch 13 irrespective of opening and closing of a recording speed changeover swtich 14. Hence, the output of the means 7 is set at the loop set region and outside the region of the circuit 10 by the high and low speed of the tape at the recording. The output becomes low and high levels through the gate 16 of the circuit 10, by which the contact 5a or 5b of the switch is selected, thus the tape speed is readily changed over at the same speed as that at the recording without making manual changing-over.</p> |
