PURPOSE: To improve the reliability of remote control by deciding an information signal carried in a carrier frequency at a deciding circuit having two threshold values, charging a differentiating circuit when the signal is not contained between the threshold values, discharging the circuit when the signal exists between the values, and decoding and reproducing the information signal with fidelity.
CONSTITUTION: An AC input is converted into a DC power supply VB and a stabilized power supply 12V or the like by a power supply circuit 3 of a transmitter-receiver 1. Further, a choke coil 9 of a signal detecting circuit 6 connected to transmission lines 5a, 5b blocks the transmitted information signal and a tuning transformer 10 detects the signal. A demodulation circuit 13 and a modulation circuit 14 are connected to the transformer 10 to provide the transmission and reception function to the transceiver 1. The circuit 13 is provided with a differentiation circuit 25 and a deciding circuit 22 comprising comparators 20, 21 having respectively the 1st and 2nd threshold values VREF1 and VREF2. Then the circuit 22 decides the information signal and when the circuit 25 is charged when no signal exists between both the VREF1 and VREF2, the circuit 25 is discharged when the signal exists, and the information signal is decoded and reproduced with fidelity.
UEKI KOUICHI
SHIRASAWA TADANORI
