Method and system for converting VGA signals to television signals including horizontally averaging and thinning scanning lines before vertically averaging the scanning lines

摘要

A video system conversion method and apparatus for converting RGB signals of a VGA system to signals for a television system such as the NTSC or PAL system and requiring reduced memory capacity. RGB signals are converted to intensity and first and second chrominance signals in scanning lines that are averaged horizontal and vertical directions. The horizontal components of the input RGB video signals are reduced in number and multiplexed, reducing the maximum capacity of a field memory. The respective intensity signal and the chrominance signals are averaged in the horizontal direction. The respective signals are thinned, i.e., reducing in number, and then averaged in the vertical direction. The circuit may include a multiplexer for multiplexing the chrominance signals after they are thinned. The circuit may include a multiplexer for multiplexing the intensity signal, and the first and second chrominance signals after the respective signals are thinned.