| 摘要 |
PURPOSE:To enable the measurement of a phase difference without hunting by inputting two input pulse trains with an inhibiting circuit to a phase comparator, and annihilating one pulse when the phase difference exceeds a prescribed value. CONSTITUTION:Respective signal waves are inputted with zero cross comparators 5, 6 and inhibition circuits 12, 13 to a phase comparator 14. When an S input signal is first triggered, an output appears only at the SO output terminals, and when an R input terminal is first triggered, the opposite state takes place. The output of the comparator 14 closes switches 15, 16 respectively which input a DC voltage B to the phase noninverted terminal and phase inverted terminal of an operational amplifier 17. The output of the amplifier 17 is inputted with a low-pass filter 18 to a meter 21. On the other hand, when the phase difference exceeds +190 deg. or -190 deg., theta comparators 19, 20 output inhibition signals 19a, 20a to anhibilate one pulse and to make the output display -170 deg. or +170 deg.. The stable display is obtd. even if there is a <=180 deg.+ or -10 deg. fluctuation in the phase difference. |
