| 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 pulse of a clock oscillator 17 of high frequency is counted by counters 18, 24, an amplitude value corresponding to a position which divides equally one period of the signals A, B into 16 is read out as a digital value from ROMs 19, 25 in accordance with a count value, it is analogized by D/A converters 20, 26, 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 each counter follows the signals A, B. A selecting circuit 23 detects that which is near an amplitude center level of the signals A, B, out of the following signals A, B, and one of the following signals A, B is selected. A rotating direction of the motor 1 is detected by a direction detecting circuit 37, a counter 28 is subjected to addition and subtraction control, and a position signal is outputted from the counter 28. |
