| 摘要 |
PURPOSE:To realize a stable reception, by receiving the key code signal transmitted through a modulation of pulse frequency at a monostable multivibrator, an integral network, a waveform shaping circuit, etc. at the receiver side. CONSTITUTION:The signal, which is modulated so as to contain one or two pulses in correspondence to 0 and 1 of the key code signal, is received at an antenna 25 of a receiver. This received signal is detected by a wave detecting circuit 26 and corrected for its waveform through a waveform shaping circuit 17 to be supplied to the clock terminal of a flip-flop 30 as well as to a clearing circuit 31 which clears the flip-flop 30. Both the output Q of the flip-flop 30 and the received output sent from the circuit 27 are supplied to an AND circuit 30, and the key code signal produced at the transmitter side is restored at the output terminal of the circuit 30. This key code signal is compared with the key code of a key code setting means 37 of the receiver side through a comparator 36. Then a drive signal is transmitted if a coincidence is obtained through the comparison. |
