Video signal analog-to-digital converter for an image display apparatus

摘要

A video signal analog-to-digital converter for an image display device comprises a reference signal generator, which can detect variations of the average level of a video signal and generate a variable upper and a variable lower reference potential in accordance with the variations detected. An analog-to-digital converting circuit A/D converts the video signal between present variable upper and lower reference potentials to produce a digital code signal. Brightness control of an LC display panel is done according to the digital code signal.