| 摘要 |
PURPOSE:To prevent transmission power from straying into a receiving system at transmission, by connecting an inductance element and a switching element between a signal circuit and a common circuit (ground). CONSTITUTION:An input terminal ''in'' is connected to a switch for transmission/ reception changeover and an output terminal ''out'' is connected to the receiving system. A forward bias is given to a control terminal ''ct'' at receiving to turn on a transistor (TR) Q11, and a prescribed frequency is coupled to the receiving system by means of capacitors C11, C12 and an inductance L11. Since the TRQ11 is controlled to be truned off at transmission and the collector capacitance of the TRQ11 is inserted in series with the inductance L11, the passing frequency is changed remarkably and the input terminal ''in'' and the output terminal ''out'' are interrupted apparently. |
