| 摘要 |
PURPOSE:To obtain a cheap and high-reliability circuit which can endure the use even under bad conditions of environment, by providing capacitors, resistances, diodes, and a gate circuit, which controls conduction of diodes, in the secondary- side terminal of an output transformer for transmission. CONSTITUTION:In the transmission and receiving circuit of a fish detector, an underwater sound detector and so on at a transmission time, the transmission signal from terminal 1 is amplified by vacuum tube 2 and is sent to transmitter and receiver 5 through output transformer 3. At this time, a negative voltage is applied to transmission and receiving switching control input terminal 20, and transistor 21 is turned off, and diodes 14 and 15 are not conductive, and the transmission signal is not transmitted to receiving-side output terminal 7. At a receiving time, a positive voltage is applied to terminal 20, and transistor 21 is turned on, and a current is flowed through resistances 16 and 17, diodes 14 and 15, and resistances 12 and 13, and diodes become conductive. Thus, the receiving signal from transmitter and receiver 5 is transmitted to terminal 7 through capacitors 10, 11, 18 and 19. |
