| 摘要 |
PROBLEM TO BE SOLVED: To enhance detection accuracy of magnitude of a carrier leakage by controlling the phase and the amplitude of a 2nd carrier output, so as to maximize the output of a difference between detection levels of output levels of an orthogonal modulation means detected respectively by 1st and 2nd detection means. SOLUTION: An adder 7 combines a carrier cancel signal received from a level adjustment device 4 and an output of an orthogonal modulator 1 and transmits a combined output. A level detector 5 detects the output level of the orthogonal modulator 1, and a level detector 5 detects a level of the synthesized output. A subtractor 8 calculates the difference between the detected outputs by the level detectors 5, 6. The subtractor 8 gives an output including a modulation signal component that is zero and the difference between carrier leakage signals required for control to a gain setting section 9 and a phase setting section 10. The gain setting section 9 and the phase setting section 10 adjust a 180-degree phase shifter 3 and the level adjustment device 4 so as to maximize the output level of the subtractor 8. Thus, the adder 7 can transmit the modulation signal where the carrier leakage components are cancelled. |
