A VGA to analog video converter is useful e.g. for displaying video and/or graphics
data from a computer onto a large screen television or television monitor. The
RGB video signals output from the personal computer are first converted to digital
form. The analog-to-digital converter which does this is clocked by a clock signal
generated by a phase-locked loop using the horizontal synchronizing signal from
the personal computer. The digital RGB signals are then converted to a YCbCR format.
A flicker filter eliminates the flickering appearing on the TV monitor by operating
on the luminance (Y) component. The YCbCr signals are encoded into NTSC or PAL
Standard, and output in composite analog video or S-VHS format. A color subcarrier
synthesizer generates the color subcarrier signal to generate an accurate subcarrier
frequency for the video output signals. An analog-to-digital clock phase adjustment
is used to ensure that the input RGB signals are sampled at the proper instant
by the analog-to-digital converters.