| 摘要 |
PURPOSE:To change a threshold value of a comparator, by providing a circuit which changes the duty ratio of an input signal at the prestage of a phase comparator. CONSTITUTION:A reference signal is given to a terminal 13, delayed at a phase shift circuit 17 and applied to a trigger terminal of a D-FF22. An input signal of an input terminal 12 is given to a D terminal of the D-FF22 via a duty ratio conversion circuit 23. The changing point of an output of a D-FF23, that is, the threshold value of a phase comparison device, can be changed by changing the duty ratio at a conversion circuit 23. |
