| 摘要 |
PURPOSE:To improve reliability, by providing a logic circuit, which detects errors in pulses due to noizes, a comparing circuit, which prevents the occurrence of distur bance in pulses due to pulsation, and a means, which latches and outputs the rotating direction when both detecting circuits agree with each other. CONSTITUTION:When an error is present in phase difference in a phase A (A) and a phase B (B) in input pulses including noizes, which are superimposed on the pulses, the error is detected with a logic circuit, which comprises three-stage D-FF 3a-3c, two-input NAND gate circuits 4, which verify the agreement of the FFs, and a three- input NAND gate circuit 5. The result is outputted to a NOR gate 8. Meanwhile, with respect to the pulsation of the pulses due to the mechanical resonance of a pulse encoder, the output of a comparator 7 becomes the stable output signal at the voltage before the pulsation occurs by decreasing a voltage E0, which is set in the comparator 7 at a value lower than a voltage when the resonance occurs. The signal is outputted to the gate 8. The agreement signal of the two detected signals, which are inputted into the gate 8, is stably latched in a latch circuit 9 and outputted. In this way, reliabil ity can be improved.
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