Sync polarity

OMG - - old VGA term as I recall.
CRT displays (Cathode Ray Tube aka TV style) could sync on one of the R,G,B colors. Later developments centered up on syncing on the Green.

"Polarity" in this context is specifically WHICH color is used as the sync (btw, we're referring to the horizontal sync).

Thousand pardons if senility has obscured the facts :sigh:
 
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