Patent ID: 8655292

Claim:
An amplifier circuit comprising: a signal separating unit that separates an input signal into a first branch signal and a second branch signal in such a manner that, as an amplitude of the input signal decreases, an amplitude of the first branch signal and the second branch signal decreases and the difference between a phase of the first branch signal and a phase of the second branch signal increases and, as the amplitude of the input signal increases, the amplitude of the first branch signal and the second branch signal increases and the difference between the phase of the first branch signal and the phase of the second branch signal decreases; a first amplifier that amplifies the first branch signal; a second amplifier that amplifies the second branch signal; and a combining unit that combines signals that are output from the first amplifier and the second amplifier together, thereby generating an output signal, wherein the signal separating unit includes a parameter acquiring unit that acquires an amplitude and a phase value of the input signal, an amplitude calculating unit that calculates an amplitude of a branch signal by using the amplitude of the input signal, a phase calculating unit that calculates a phase amount of the first branch signal by using both the amplitude of the input signal and the amplitude of the branch signal that is calculated by the amplitude calculating unit, a phase inverting unit that inverts the sign of the phase amount of the first branch signal, thereby calculating a phase amount of the second branch signal, a multiplier that multiplies a unit vector and the amplitude of the branch signal together, wherein the unit vector has an amplitude 1 and a phase 0, a first phase shifter that shifts the amplitude of the branch signal that is output from the multiplier by the phase amount of the first branch signal that is calculated by the phase calculating unit, a second phase shifter that shifts the amplitude of the branch signal that is output from the multiplier by the phase amount of the second branch signal that is calculated by the phase calculating unit, a third phase shifter that shifts a signal that is output from the first phase shifter by the phase value of the input signal, and a fourth phase shifter that shifts a signal that is output from the second phase shifter by the phase value of the input signal.