This "ripple" is called "tearing". It's just the price of emulation.
Set MAME to use triple buffering, and your problems will be done away with.
If you can't, use SmoothMame, which forces all roms to be run at the same rate, not their odd weird funky one (like most capcom fighters.)
EDIT: I have no idea why this would happen on an arcade monitor and REAL board.
(unless he had some funky setup)