| 摘要 |
PURPOSE:To prevent an erroneous input data due to a noise, etc., by generating a scanning signal of a constant period to an input data, discriminating whether it is a normal data or not, and also detecting that a zero period of the input data does not exists in a gate scanning period of the scanning signal. CONSTITUTION:To an electronic computer or a microprocessor 1, a digital input device 2 is connected, an input data A is inputted to a holding circuit 6, and at fall of a gate scanning signal B by a program, the data A is set to the circuit 6. In a period in which an output D of this circuit 6 is set to ''1'', the signal A is continued, and also the signal B is set, an output E of an AND gate 7 is set to a state of ''1''. This state is decided by a data deciding logic 5 for inputting the signal B, and a data deciding result C is outputted. When scanning an input gate, if a ''0'' period of the signal A exists in a period in which the signal B is set even if the signal A is ''1'', the output E of the gate 7 beomes ''0'', a data is decided to be ''0'', and an input error due to a noise, etc. is prevented. |
