| 摘要 |
PROBLEM TO BE SOLVED: To provide a power amplification circuit capable of suppressing gain decreases of a power amplifier due to increase in input signal power in a state near the saturation operation, capable of reducing its side, and low in distortion and high in efficiency and to provide a communication unit using the circuit. SOLUTION: The power amplification circuit is provided with the power amplifier 12 and a negative feedback circuit 13 connected between a signal input terminal and a signal output terminal of the power amplifier 12. The impedance of the negative feedback circuit 13 dependents on a signal voltage occurring across the negative feed back circuit 13. By adjusting the characteristic that the negative feedback quantity of the negative feedback circuit 13 to the power amplifier 12 is variable depending on input signal power, gain fluctuations of the power amplifier 12 due to increase or decreases of input signal power or output signal power around specified output signal power are suppressed.
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