| 摘要 |
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.
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