PURPOSE: To obtain high S/N of the output and to facilitate temperature compensation and compensation of dispersion in amplification elements by controlling a 2nd amplifier with a high efficiency by a power supply current of a 1st amplifier with excellent linearity.
CONSTITUTION: An input signal inputted to a terminal 10 is divided into two and fed to a 1st amplifier 11 and a 2nd amplifier 12. The amplifier 11 is an amplifier with excellent linearity and the amplifier 12 has a high efficiency but its linearity is the class F. Then a power supply voltage control circuit 13 detects a signal in response to a power supply current from the amplifier 11 and the power supply voltage of the amplifier 12 is controlled based thereon to linearize the amplifier 12. The power supply current of the amplifier 11 is proportional to the input signal amplified depending on the characteristic of the amplifier element in use when the amplifier 11 has an excellent linearity. The circuit 13 controls the power supply voltage of the amplifier 12 according to the power supply current of the amplifier 11, a signal of low distortion is obtained at a terminal 14. Then deterioration in the S/N is eliminated and temperature compensation and compensation of dispersion in the amplifier element are facilitated.
IINO KOJI
OBAYASHI SHUICHI
SEKINE SHUICHI
