EER MODULATION AMPLIFIER DEVICE

摘要

PPROBLEM TO BE SOLVED: To suppress modulation distortion when performing amplitude modulation by power source control of a high-frequency amplifier. PSOLUTION: An inputted high-frequency signal is separated into an amplitude signal and a phase modulation signal by a polar modulation unit 102, and the amplitude signal is amplified by an amplitude amplifier unit 104 and inputted into the power source terminal of a final stage high-frequency amplifier 107. The phase modulation signal is subjected to amplification and amplitude modulation by a high-frequency preamplifier 105 and the amplifier 107, and a modulation amplified signal is outputted. In this case, the amplifier 107 uses a feedforward circuit 113 consisting of a directional coupler 106, a delay line 108, an amplitude adjustor 109, a phase shifter 110, and a directional coupler 111 to perform feedforward control and to improve deterioration in characteristics of a modulation amplified signal generated due to amplitude modulation. That means, one part of a phase modulation signal to be inputted into the amplifier 107 and a leakage signal to be outputted from the amplifier 107 are added at the same amplitude and a reverse phase, thereby eliminating a modulation distortion component. PCOPYRIGHT: (C)2006,JPO&NCIPI