| 摘要 |
PURPOSE:To make a device small in size, and to obstruct exactly a malfunction by using an IC for a signal filter circuit, operating it by a clock, and eliminating a noise inputted into a digital circuit. CONSTITUTION:Input and output sides of a noise filter circuit 10 are connected to a phototransistor (TR) 1 and an input buffer IC5, respectively, and an output of the TR1 is connected to a digital IC of a J1 input and a K1 input of an FF6 of the first stage, an AND gate 7, an OR gate, etc. Its output is connected to a J2 input and a K2 input of an FF9 through gates 7, 8, and connected to an input side of an output buffer 5 from an output Q2. When an input signal of ''H'' exists in a state of ''L'', if its pulse width is above a clock period of the FFs 6, 9, an output of the FF9 becomes ''H'', but if said width is below the clock period, the Q2 output remains ''L'' and it is not varied. Also, when an input signal of ''L'' exists in a state of ''H'', too, in case that said pulse width is above the clock period, the Q2 output becomes ''L'', and in case that it is below the clock period, the Q2 output becomes ''H'', in the same way. |
