| 摘要 |
PURPOSE:To improve the potential voltage standing wave ratio of an input and an output by connecting an impedance matching resistance between a connecting point of an input selecting circuit and an output selecting circuit, and a ground terminal. CONSTITUTION:Impedance matching resistors 11-14 are connected across connecting points of selecting circuits (SW1, SW3, SW5 and SW7) and output selecting circuits (SW2, SW4 and SW6), and ground terminals. This circuit becomes a pi type resistance connecting circuit of by adding resistor 18 in parallel with both ends, and can convert the input/output impedance to 50 ohms. Accordingly, by setting the resistors 11, 14 to 238 ohms and setting the resistors 12, 13 to 119 ohms of a half value, a block matched to 50 ohms is constituted extending from a second switch SW2 to a seventh switch SW7, respectively. In such a way, the VSWR deterioration caused by a multistage connection of a switch is suppressed. |
