| 摘要 |
PURPOSE:To compensate amplitude and phase distortion by detecting a phase difference between input and output signals of the power amplifier, rotating the phase of an input base band signal in response to the phase difference, generating a modulation wave signal and implementing feedback with a signal of an orthogonal coordinate signal. CONSTITUTION:A phase difference detection means 1 detects a phase difference between input and output signals of a power amplifier 15. Then a phase rotation device 54 rotates a phase of an input base band signal in response to the phase difference and inputs the result to an orthogonal modulator 11, in which orthogonal modulation is implemented to generate a modulation signal. Furthermore, an amplitude difference detection means 2 detects an amplitude difference between an input envelope component and an output envelope component of the amplifier 15. Then an amplitude modulator 13 applies amplitude modulation to an output modulation signal of the orthogonal modulator 11 in response to the amplitude difference to generate an input signal to the amplifier 15. Thus, feedback is implemented by using a signal of an orthogonal coordinate system to compensate both the amplitude distortion and the phase distortion of the power amplifier. |
