Apparatus for processing video signals and employing phase-locked loop

摘要

Apparatus for processing video signals and which can be connected with a personal computer for further processing. An analog to digital converter samples and converts input NTSC composite video signal into digital signal for subsequent processing. A phase-locked loop provides sampling clock signal to the ADC, and also ensures accurate sample phase. Based on a theory that human eye is more sensitive to the luminance component of video signals, a double sampling circuit is included which double samples the luminance component of a video signal to improve the overall resolution of an image.