A transmitter circuit has two mixers that modulate a carrier wave
according to an input signal, outputs a signal having information in a
phase and an amplitude, detects a DC offset in each of the mixers, and
adds a DC voltage that corrects the detected DC offset to the input
signal of the mixers. The mixer is a double balanced mixer having two
load resistors, and the transmitter circuit has a resistor that is
connected between a node of two load resistors and a power supply, a
limiter amplifier that amplifies a signal, and a control unit that
changes first and second potentials using a signal that is outputted by
the limiter amplifier. The first and second potentials become a potential
of the DC voltage that corrects the DC offset.