Accurate on-site reference for automatic size and position adjustment

摘要

Determining a phase shift compensation for automatically centering an image by measuring a start time delay between a horizontal scan line signal and an active video signal, measuring an end time delay between the active video signal and the horizontal scan line signal, and computing a phase shift for a horizontal flyback signal using the start time delay and the end time delay. A system to center an image on a monitor includes a video processing circuit and a rasterizer. The video processing circuit receives a video signal and measures a start time delay and an end time delay between a horizontal scan line signal and an active video signal. The circuit generates a phase shift used to generate a horizontal flyback signal using the measured start time delay and the end time delay. The rasterizer receives the output of the video processing circuit to control a scanning element.