Patent ID: 8472556

Claim:
An amplifier device, comprising a predistorter, a predistortion controller, a digital to analog (D/A) converter and an amplifier unit, the predistorter predistorts a digital signal to be amplified, the D/A converter converts the predistorted digital signal to an analog signal, the amplifier unit amplifies the analog signal, and the predistortion controller controls the predistorter in accordance with a signal fed back from the amplifier unit, wherein, the predistortion controller determines, respectively, power of a left side lobe and power of a right side lobe of two side lobes of a frequency spectrum of the signal fed back from the amplifier unit, determines a cost function in accordance with the power of the two side lobes, and controls the predistorter in accordance with the cost function, the predistorter is one of the following two types of structures: structure 1: the predistorter comprises a filter unit and a phase amplitude predistortion data generation unit, the phase amplitude predistortion data generation unit generates data after an amplitude predistortion and a phase predistortion, the filter unit filters at least one of data inputted to and outputted from the phase amplitude predistortion data generation unit; structure 2: the predistorter comprises n phase amplitude predistortion data generation units, (n−1) delay units and an adder, the (n−1) delay units delay input data, respectively, to generate (n−1) delayed input data, the n phase amplitude predistortion data generation units predistort undelayed input data and the (n−1) delayed input data, respectively, to generate n data after an amplitude predistortion and a phase predistortion, the adder adds the data after the amplitude predistortion and the phase predistortion from the n phase amplitude predistortion data generation units, wherein n is an integer greater than or equal to 2.