| 摘要 |
PURPOSE:To attain the simultaneous control of both the oscillation frequency and the output level through a single oscillating circuit in response to the set-up of a variable setting part, by providing an output control part, an oscillation part formed at the next stage of the output control part and the variable setting part connected to said output control part and oscillation part. CONSTITUTION:An emitter current IE1 of a transistor TR1 is shown by an equation I when a resistor R1 is selected with the circuit power supply voltage kept at V. While the emitter current IE2 of the TR1 is shown by an equation II when a resistor R2 is selected. Therefore R1<R2 is satisfied and the resistor R1 is selected in a transmission mode when the output level is kept at a high level. Then the resistor R2 is selected in a reception mode when the output level is kept at a low level. In other words, a switch S1 is switched in response to the reception and transmission modes. Therefore a high oscillation frequency and the output of a high level are delivered between termianl T1 and T2 when the resistor R1 is selected. While a low oscillation frequency and the output of a low level are delivered between terminals T1 and T2 when a resistor R2 is selected. |
