PURPOSE: To send a reception signal with a fast response at leading of power supply by turning off a switch circuit just after application of power so as to supply the output of an amplitude limit amplifier/FM demodulation circuit to a base band signal amplifier circuit via a 1st coupling capacitor.

CONSTITUTION: A switch circuit 12 is turned off just after application of power, an FM demodulation output is inputted from an amplitude limit amplifier FM demodulation circuit 4 to a base band signal amplifier circuit 7 via the 1st coupling capacitor 6 and the base band signal amplifier circuit 7 supplies the output in a fast response with respect to the high speed inputted signal received while DC fluctuation is large. Then the switch circuit 12 is turned on in a prescribed time delayed after application of power, a demodulation signal outputted from the amplitude limit amplifier FM demodulation circuit 4 is inputted to the base band signal amplifier circuit 7 through 1st and 2nd coupling capacitors 6, 10 and even a low speed signal is received. Thus, the demodulation signal with a fast response is obtained to a demodulation signal with a large DC fluctuation just after application of power.