Patent ID: 8466755
Filing Date: 2013-06-18
Classification: H03F

Abstract:
1. A polar modulation apparatus comprising: a data generator for generating, from a baseband signal, an amplitude component signal and a phase component signal; a phase modulator for generating a phase modulated signal obtained by phase modulating the phase component signal; an adder for adding an amplitude offset voltage to the amplitude component signal; a power amplifier, which includes a first hetero-junction bipolar transistor, for amplifying the phase modulated signal by using the amplitude component signal; a monitor unit for monitoring the power amplifier and outputting a monitor voltage; and a control unit for calculating the amplitude offset voltage according to the monitor voltage and outputting the calculated amplitude offset voltage to the adder, wherein the monitor unit includes a second hetero-junction bipolar transistor and outputs, as the monitor voltage, a collector-emitter voltage which is obtained when a base current and a collector current of the second hetero-junction bipolar transistor are fixed to respective predetermined values.