| 摘要 |
PURPOSE:To fetch only an FM multiplex portion at an IF stage, and to simplify an FM demodulator by providing a circuit for separating an FM modulating signal of a digital data from an IF signal, and a circuit for demodulating a signal from this separation circuit. CONSTITUTION:An output of an antenna 1 reaches an IF stage of B through a frequency converter 2 of a tuner part, and a signal of B is inputted to an FM demodulator 4 and an FM multiple signal separating circuit 6. A signal from the demodulator 4 becomes signals ER 8, EL 9 of the right ear and the left ear by a stereoscopic demodulator 7 through an LPF 5, and in the circuit 6, an input signal is separated into a stereoscopic modulating signal and a digital signal, applied to a decoder 10 of a digital data, and a data signal 11 is outputted. In this case, in a state of an IF signal form modulated by the FM by applying the IF stage of B to the circuit 6, an FM modulating signal of the digital data is separated, and output of the circuit 6 is provided on the FM demodulator for the digital data, and a data signal is fetched. In such a way, only an FM multiple portion can be fetched by the IF stage, and the FM modulator can be simplified.
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