| 摘要 |
PURPOSE:To obtain a position signal which is precise and having scarcely a ripple, by detecting a detecting level of two signals different in 1/4 period phase generated in accordance with movement of an object which moves or rotates in two directions, by subdividing it as to its position. CONSTITUTION:A motor 1 rotates and a rotary encoder 2 generates signals A, B of two phases different in 1/4 phase each other. A clock oscillator 17 generates a clock pulse of high frequency from the signals A, B, it is counted by counters 18, 24, and a digital value is outputted from ROMs 19, 25 in accordance with a count value. An amplitude value of a position which divides equally one period of the signals A, B into 16 is stored in the ROMs 19, 25, its read-out data is analogized by D/A converters 20, 26, respectively, is compared with the signals A, B by comparators 21, 27, and in accordance with its result, the counters 18, 24 are added and subtracted, and follow the signals A, B. A signal being near an amplitude center level is selected by a selecting circuit 23, a multiplexer is controlled, a direction is detected by a direction detecting circuit 49, and a position signal is outputted from a counter 45. |
