POLAR MODULATION TRANSMITTER CIRCUIT AND COMMUNICATIONS DEVICE

摘要

Provided is a transmitter circuit capable of operating with low distortion and high efficiency even in a modulation method using wide modulation bandwidth. In the transmitter circuit, a signal generation section (11) generates an amplitude signal and an angle-modulated signal. Based on a predetermined characteristic, a compensating filter (12) wave-shaping-processes the amplitude signal. A regulator (14) outputs a signal in accordance with a magnitude of the signal which has been wave-shaping-processed by the compensating filter (12). An amplitude modulator section (15) amplitude-modulates the angle-modulated signal by using the signal outputted from the regulator (14). A characteristic of the compensating filter (12) is an inverse of a transfer characteristic between an input at the regulator (14) and an output at the amplitude modulator section (15).