| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission amplifier which facilitates the adjusting operation of frequency characteristics and the switching of operation frequency bands. SOLUTION: An oscillator 15 switches the output destination of a pilot signal from a main amplifier 4 to a preamplifier 16 in a frequency characteristic correction mode. In the preamplifier 16, the grounding capacity between a signal line and the ground can be easily adjusted, and when the pilot signal is inputted from the oscillator 15, the preamplifier 16 superimposes the pilot signal on an input signal. A detection circuit 12 detects a pilot signal outputted from a directional coupler 11. A control circuit 14 finds the frequency characteristics of the transmission amplifier on the basis of the level of the pilot signal and controls the grounding capacity of the preamplifier 16 so as to make the frequency characteristics flat. |
