| 摘要 |
PURPOSE:To exclude the switch required for the transmitter/receiver plus the con trol circuit for the switch, by connecting the ciruit to which the diode and the resistance are connected in parallel between an amplifier and the transmission line and then making use of the impedance characteristics of the diode. CONSTITUTION:The impedance control circuit to which two units of diodes 31 and 32 plus a resistance are connected in parallel is connected between the amplifier 26 and the line 32A of one side and connected to the transmission line 11. At the same time, the other line 23B connected to the line 11 is connected to the amplifier 26 as well as to the earth side of the receiving circuit 24. The transmission side of the circuit 24 is connected directly to the line 23A. Accordingly, the circuit is always connected to the line 11, and the amplifier 26 of the transmission side is also connected to the line 11 at all times via the impedance control circuit. |
