In order to improve various characteristics of a receiving circuit for digital
radio services, circuits are provided for forming two local oscillation signals,
whose frequencies are both the center frequency between a first ensemble and a
second ensemble, and whose phases differ by 90 from each other. Furthermore,
there are provided mixer circuits for frequency-converting the received signal
into intermediate frequency signals in accordance with the local oscillation signals,
phase-shift circuits to which the intermediate frequency signals are supplied,
and an addition/subtraction circuit for performing one of addition and subtraction
of the outputs of the phase-shift circuits. In addition, there are provided intermediate
frequency filters to which the output signal of the addition/subtraction circuit
is supplied and demodulation circuits to which the output signals of the intermediate
frequency filters are supplied. By switching the process in the addition/subtraction
circuit to addition or subtraction, the signals of the first ensemble and the second
ensemble are selectively extracted from the demodulation circuits.
