| 摘要 |
PROBLEM TO BE SOLVED: To prevent unnecessary radiation from an antenna and to prevent the deterioration of error-rate characteristics due to a DC offset. SOLUTION: A power divider 104 distributes an RF signal amplified by an RF amplifier 103 into four of a first RF signal to a fourth RF signal. Phase shifters 105 to 107 phase-shift the second RF signal to the fourth RF signal by 180 deg., 90 deg. and 270 deg. respectively. A first base band signal to a fourth base band signal are generated respectively by mixing the first RF signal and the phase-shifted second to the fourth RF signals and a local signal from a local oscillator 112. Adders 113 and 114 take the difference between the first base band signal and the second base band signal, and the difference between the third base band signal and the fourth base band signal, respectively.
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