| 摘要 |
PURPOSE:To remove noise in a detected output, and to prevent a trouble due to the loss of a detection pulse and the attenuation of level by providing a noise removing circuit that responds a specified state of an infrared-ray signal pulse from a detection circuit and a pulse generating circuit that responds the output of the noise removing circuit. CONSTITUTION:The noise removing circuit 16 generates output C only when the output pulse of the detection circuit continues at least more than two, and the pulse interval is within a specified time. That is, when the terminal voltage B of a condenser 20 caused by above-mentioned continuous pulse exceeds a reference comparison voltage Vr inversion is made by a charae discharge circuit 22 and a comparator circuit 24, and an output is not made by the single pulse of the nature of noise. The pulse generating circuit 18 receives above-mentioned output C as trigger input of an FF circuit 52 and obtains a pulse in fixed time width from non-inversion output Q of the FF circuit 52 by a time constant circuit 56 and a comparator 58. |
