A receiving circuit of a direct conversion system is provided which
includes a differential amplifier circuit which amplifies a received
signal, a mixer which combines the amplified received signal and an
oscillation signal having a predetermined frequency to thereby perform
frequency conversion, and a high gain amplifier circuit in which a
plurality of programmable gain amplifiers and a plurality of filters
which eliminate noise of the received signal and an unnecessary wave, are
connected in a multistage and which is configured such that an
amplification factor is varied according to the level of the received
signal. In the receiving circuit, the low noise amplifier is brought to a
non-operating state to thereby allow execution of a DC offset cancel
operation of the corresponding programmable gain amplifier on the
pre-stage side of the high gain amplifier circuit. Thereafter, the low
noise amplifier is brought to an operating state to thereby allow
execution of a DC offset cancel operation of the final-stage programmable
gain amplifier.