| 摘要 |
PURPOSE:To allow signals to pass through not an amlifier, but an output terminal by simple constitution by inserting a varactor diode applied with a reverse bias into the matching circuit of an amplifier and by making the impedance of the input- output terminal different from that of the line when the power supply is cut off. CONSTITUTION:Signals are allowed to pass through with a little loss after being amplified when the power is being applied and without being amplified when the power is cut off. To the input side of network 23 in matching circuit 26 connected to input terminal 47, the series circuit composed of varactor diode 22 and capacitor 24 is connected and the connection point between capacitor 24 and diode 22 is connected to power terminal 20 via power-supply switch 21. In addition, amplifying transistor 25 is provided between circuit 26 and matching circuit 33, and the series circuit of variable capacitor 32 and varactor diode 31 is provided to the output side of network 30 of this circuit 33; and then, this connection point is connected to power-supply switch 21, and output terminals 34 and 34' of the circuit is connected to the point where the output terminal of network 30 and capacitors 24 and 32 are connected to input terminal 27'. |
