A/D CONVERTER

摘要

PURPOSE:To realize the A/D converter unnecessitating a troublesome job such as manual adjustment by the user or the like through visual observation of an output screen with respect to a phase shift between a clock signal and a video signal changing when an input device is changed when the video signal of a computer or the like is subjected to A/D conversion with a dot clock signal. CONSTITUTION:A video signal 1 is sampled by using a clock signal resulting from a dot clock signal 4 passing through a variable delay device 6 and fixed DELTAT delay devices 13, 14 or the like, and a phase detection section 18 detects a phase shift between the video signal and the sampling clock signal by using obtained sampling values Y(n.T) 16, Y(n.T-DELTAT) 17 and Y(n.T+DELTAT) 15. Then a delay quantity control section 19 controls the variable delay deice 6 in response to the detected phase shift to sample the video signal in a proper timing.