| 摘要 |
PURPOSE:To prevent the mis-operation of a remote operation device by a noise, by means of discriminating by using a NAND gate that a signal is added to at least two frequency discriminating circuit among a purality of frequency discriminating circuits, and of stopping the control circuit. CONSTITUTION:Each NAND gates 15,16,17 whose center frequencies are f1, f2,f3, are L,H,H in each input and are H in an output when a signal is not reached. When the signal is received by a microphone 1, it is amplified by an amplifier 2, and the output A of a frequency discriminating circuit 3 becomes to H, and the output of the NAND gate 15 is changed from H to L. When a noise is reached at the microphon 1, the outputs of frequency discriminating circuits 4,5 are changed from L to H. From the result of this, the inputs of the NAND gate 15 become to L,L,L, the inputs of the NAND gate 16 become to H,H,L, and the inputs of the NAND gate 17 become to H,L,H, and whichever output vecome to H and does not allowed control circuit 6,7,8 to be drived. |
