| 摘要 |
PROBLEM TO BE SOLVED: To provide a power amplifier that is free from lowering power efficiency regarding the power amplifier. SOLUTION: The power amplifier has a branch circuit 1 for inputting an RF signal and branching the RF signal in at least two directions, a matching circuit 2 for receiving an output from the branch circuit 1, a plurality of amplifiers 3 for directly receiving the output from the matching circuit 2 or the output from the branch circuit 1 and having different saturation powers and the matching circuit 4 for receiving the outputs from the amplifiers 3. The power amplifier further has a synthesizing circuit 5 receiving the output from the matching circuit 4, a modulated-wave envelope conversion section 6 receiving a modulated-wave envelope signal and converting the amplitude and a drain-voltage supply section 7 receiving the output from the modulated-wave envelope conversion section 6, converting the output into a drain voltage and supplying the resulting voltage to a drain terminal of the amplifier 3. The output from the synthesizing circuit 5 is used as the output from the power amplifier. COPYRIGHT: (C)2009,JPO&INPIT
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