Definition: NTSC

(National TV Standards Committee) The first television standard for the U.S., which was also adopted by Canada, Japan, South Korea and several Central and South American countries. In the U.S., the analog NTSC standard was superseded by the digital TV standard in 2009 (see digital TV transition and DTV).

From Monochrome to Color
NTSC commercial broadcasting began in the U.S. for black and white TVs in the summer of 1941. A subcarrier frequency was later developed to transmit color alongside the monochrome signal, and color TV debuted on January 1, 1954 (see composite video). Before electronic TV became a standard, prototype electromechanical systems produced the first, crude video images (see video/TV history).

NTSC Specifications
Administered by the FCC, NTSC broadcast 60 half frames per second, which is known as 60 "fields" per second in TV jargon (59.94 fields per second to be exact). NTSC used 525 lines of interlaced resolution (two 262.5-line half frames). The last 21 lines in each half frame were the "vertical blanking interval" (VBI), which gave the electron gun in the CRT time to reposition itself from the bottom of the last frame to the top of the next. See interlace and raster scan.

The digital video (DV) camcorder format that is equivalent to NTSC is 720x480 pixels (see DV). The digital TV equivalent is 704x480 pixels (see DTV).

NTSC was encoded in the YUV color space, which provides a mathematical equivalent of red, green and blue. It also includes an audio FM frequency and an MTS signal for stereo. See NTSC DVD, YUV, YIQ, 4fSC, vertical blanking interval, aspect ratio, DTV, PAL and SECAM.

An NTSC TV Set

This TV set picked up the first NTSC TV signal, which was broadcast in the U.S. in 1941. The signal was monochrome. In 1954, the new NTSC standard added color using a composite video signal. (Image courtesy of TVhistory.TV)

Inside a TV?

Hard to imagine, but this rotating disc was the heart of the first TV camera and receiver, which predated the all-electronic systems such as NTSC. For an overview, see video/TV history. (Image courtesy of TVhistory.TV)