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NTSC - technical definition

The initial standard (1953) for broadcast television, NTSC was named for the committee that established it in the United States. NTSC is characterized as analog in nature, with 525 interlaced scan lines. There are 640 pixels per line, 485 of which are dedicated to the active picture.The frame rate is 30 fps, 60 fields interlaced, and the aspect ratio is 4:3. As an early analog standard that is viewed by some as overly complex and ineffective in a contemporary digital context, NTSC sometimes is referred to by its detractors in the pejorative as Never The Same Color. NTSC is defined in ITU-R Recommendation 1125 and served as the baseline for subsequent standards, Phase Alternate Line (PAL) and SECAM (S

See NTSC in Computer

(National TV Standards Committee) The committee that developed the television standards for the U.S, which are also used in Canada, Japan, South Korea and several Central and South American countries. Both the committee and the standard are called "NTSC."

Frames and Resolution
Administered by the FCC, NTSC broadcasts 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 uses 525 lines of resolution: the first 480 lines in each frame are the image, and the last 45 are the "vertical blanking interval" (VBI), which was designed to give the electron gun time to reposition itself from the bottom of the last frame to the top of the next. See interlace and raster scan.

Color and Audio
NTSC is 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 YUV, YIQ, 4fSC, vertical blanking interval, aspect ratio, DTV, PAL and SECAM.

Monochrome to Composite
In 1940 and 1941, the NTSC met to develop the monochrome TV standard, and commercial broadcasting began in the U.S. for black and white TVs on July 1, 1941. The Committee met again from 1950 to 1953 and added a subcarrier frequency to the black and white signal in order to transmit color in a composite signal (see composite video). Color TV began in the U.S. on January 1, 1954.

Before totally electronic TV cameras and receivers were built, electromechanical "scanning disc" systems produced the first TV images. See video/TV history for an overview.

An NTSC TV Set

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

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