A high frequency signal selected via a pre-filter is inputted to first and
second frequency conversion circuits together with a local oscillation
signal. The first and second frequency conversion circuits each output a
difference frequency component between both input signals. An output
signal of the first frequency conversion circuit is inputted to an
intermediate frequency filter while an output of the intermediate
frequency filter is inputted to an amplifier. An output signal of the
first frequency conversion circuit is inputted to an amplifier. The
amplifier selects and amplifies any one of an intermediate frequency
signal outputted from the intermediate frequency signal and an output
signal of the second frequency conversion circuit, and thereafter, output
it.