| 摘要 |
PURPOSE:To discriminate accurately the direction of rotation even if the revolving speed of a rotating body is changed over a wide range, by providing the direction detecting means detecting one direction of rotation of the rotating body and detecting the other direction of rotation of the rotating body based on an input of both output signals of the 1st and the 2nd delay circuit. CONSTITUTION:A photoelectric signal as a detecting signal A of a photoelectric element 7c is shaped into a rectangular wave at a waveform shaping circuit 10. Further, the detecting signal A is shaped into rectangular wave signals B, C at slice circuits 11, 12 comprising with a Schmitt trigger circuit. The 1st delay circuit 13 inputs the signal B and outputs a rectangular wave signal D delaying only the rise, in this case, the start timing of the rectangular pulse for a prescribed time. The 2nd delay circuit 14 inputs the signal C, and outputs a rectangular wave signal E delaying the start timing of the rectangular pulse, i.e. only the rise for a prescribed time. Further, the direction detecting means comprises with AND circuit 16, 17, an inverter 18 and an RS-FF19. |
