| 摘要 |
PROBLEM TO BE SOLVED: To simplify a circuit scale and adjustment by feeding-back the output of a power amplifier when an orthogonally modulated modulating signal is level adjusted and amplified to an orthogonal modulator and adjusting the level of a return side attenuator. SOLUTION: The orthogonal modulator 1 orthogonally modulates a local signal and the power amplifier 3 amplifies the modulating signal which is level- adjusted by a forward-side attenuator(ATT) 2 so as to output it. A forward-side detecting means 4 detects the gain of the power amplifier 3 and a forward-side adjusting means 6 adjusts the forward-side ATT 2 so as to permit difference between the signal detected by the forward-side detecting means 4 and a set value to be zero. Moreover, the return-side ATT 7 permits the input signal of an orthogonal demodulator 10 to be variable. A return-side adjusting means 9 adjusts the return-side ATT 7 so as to permit difference between the gain of the orthogonal demodulator 10 detected by the return-side detecting means 8 and the set value to be zero and the signal demodulated by the orthogonal demodulator 10 is fed-back to the orthogonal modulator 1. |
