| 摘要 |
PURPOSE:To prevent malfunction by comparing the zero cross cycle of a frequency deviation carrier relay with those of the 1st and 2nd frequency signals of a preset frequency and by deciding as the 1st or the 2nd frequency signal if their zero cross cycles are the same. CONSTITUTION:A carrier relay signal A inputted into an input terminal 1 is converted into a rectangular wave B with a Schmidt trigger circuit 2 and inputted into monomulti-vibration circuits 3 and 4 and an inverter circuit 5 at the same time. The outputs C and D of the monomulti-vibration circuits 3 and 4 are inputted into an AND circuit 6 and an AND logic output E is made to serve as a reference cycle signal for comparison. This reference cycle signal and a carrier relay signal F reversed by the inverter circuit 5 are compared with a flip-flop circuit 7 and if it is within the reference cycle, 1 is outputted, while if it is beyond the reference cycle, 0 is outputted. By performing noise detection simultaneously with the remodulation of signals, the occurrence of an error can thereby be prevented. |
