TRANSMISSION CIRCUIT AND COMMUNICATION APPARATUS EMPLOYING THE SAME

摘要

A small-size transmission circuit is provided which outputs a transmission signal having high linearity independently of a magnitude of an output power, and operates with high efficiency. A signal generating section (11) generates quadrature data based on input data. A computation section (12) compares a predetermined amplitude component of the quadrature data with an amplitude threshold value, and outputs an amplitude signal, a first phase signal, and a second phase signal. A regulator (17) outputs a voltage controlled depending on the amplitude signal. An angle modulation section (13) and an angle modulation section (14) angle-modulate the phase signal to output first and second angle-modulated signals. An amplitude modulation section (15) and an amplitude modulation section (16) amplitude-modulate the first and second angle-modulated signals using a voltage controlled depending on the amplitude signal to output the angle-modulated and amplitude-modulated signals as a first modulated signal and a second modulated signal. A combining section (18) combines the first and second modulated signals to output a transmission signal.