| 摘要 |
PURPOSE:To make the total gain of a power amplifier constant equivalently and to make an input level of a satellite repeater constant as a result by controlling an input signal level inputted to the power amplifier in response to number of transmission channels. CONSTITUTION:A ROM 7 receiving a transmission control signal is a ROM table generating a level signal for gain control in response to number of operat ing channels, a D/A converter 8 and a filter 9 convert the bit information outputted from the ROM 7 into an analog signal and give the signal to a gain control amplifier 3 as a gain control signal. Gain control information is written in the ROM 7 so that the gain of the gain control amplifier 3 of the pre-stage is g-DELTAG1 when the gain of a power amplifier 4 to which an input signal corre sponding to the unity of the transmission channel number is inputted is G-g+DELTAGT1. It is possible to make the total gain of the power amplifier to be G based on the similar concept as to other transmission channel number and the power amplifier with a constant gain is constituted independently of the transmission channel number. |
