| 摘要 |
PURPOSE:To correctly detect the condition of a phase by inputting first and second period signals in which a phase is mutually changed and discriminating the phase condition of the first and second period signals from the relation of the logical difference in the logic of either of signals before and after the condition is changed. CONSTITUTION:In a phase comparing circuit F, for example, first and second period signals A and B, in which the phase is mutually changed, such as the output pulse of the rotary encoder of two elements are inputted, the logical difference between the exclusive OR before the condition change of the signals A and B and the exclusive-OR after the condition change is obtained and the logical difference before the condition change and after the condition change of either of these signals is obtained. It is judged that when these two logical differences are for example positive, the phase is advanced and when either of them is negative, the phase is delayed or equal. Thus, with the simple constitution, the advance, delay and simultaneous of the phase can be correctly detected. |
