| 摘要 |
PURPOSE:To detect the position theta of a high speed rotating object by forming a signal sin(theta-alpha)sinomegat based on a difference of modulation signals of biphase signals and changing the duty of a switch control signal so as to make a term sin(theta-alpha) zero. CONSTITUTION:Counters 61, 62 are preset so as to halve the content of the counter 62 with respect to a count capacity with the content of the counter 61 set zero. Further, an output S63 of a comparator 63 goes to an H level when S63<S5B and an output S64 of a comparator 64 goes to an H level when S64>=S5B. A selector 66 selects the outputs S63, S64 of the comparators 63, 64 to be matched with a prescribed timing. In constituting the control lop as above, it is possible to control alpha so that the term sin(theta-alpha) is always zero. Since one pulse of an output of a voltage controlled oscillator has a weight for one pulse of division number, the moving quantity is detected with high resolution by counting and accumulating the pulses by a counter provided separately.
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