NTSC – (National Television System Committee) - The NTSC is responsible for setting television and video standards  in the United States, Japan, Canada and Mexico. (In Europe and the rest of the world, the dominant television standards are PAL and SECAM.)
   The NTSC standard is incompatible with most computer video standards which often use RGB video signals. However, you can insert special video adapters into your computer that convert NTSC signals into computer video signals and vice versa.  When someone refers to a television signal as a "NTSC signal" they're generally talking about the dominant analog signal used throughout North and Central America.  https://en.wikipedia.org/wiki/NTSC
NTSC Video - NTSC Video is the National Television Standards Committee's method that's used in the U.S. for electronically creating a color television signal.  https://en.wikipedia.org/wiki/NTSC