| 摘要 |
<p>In a radio transmission amplifier unit which has between input and output terminals a gain-controlled amplifier 11, a pre-amplifier 12 connected to the output thereof and a main amplifier 13 supplied with the output therefrom, the range of the transmitting power level is divided into small, medium and large regions. In the small transmitting power level region, the power supply to the pre- and main amplifiers is cut off by power-supply switches 28 and 29 and the output of the gain-controlled amplifier 11 is connected to a terminal 14 via switches 15, 18 and 19; in the medium transmitting power level region, the power-supply switch 28 is turned ON and the switch 29 OFF to connect the switch 15 to the pre-amplifier and the output of the pre-amplifier is connected to the terminal 14 via switches 21 and 19; and in the large transmitting power level region, the power-supply switches 28 and 29 are turned ON to connect the switch 15 to the pre-amplifier, a switch 16 is connected to the main amplifier, and the output of the main amplifier is connected to the terminal 14 via the switch 19. <IMAGE></p> |
