NTSC (National Television System Committee) is the analog television system used in most of the Americas, Japan, South Korea, Taiwan, Burma, and some Pacific island nations and territories (see map). NTSC is also the name of the U.S. standardization body that adopted the NTSC broadcast standard.National Television System Committee (1951-1953), and Reports of Panel No. 11, 11-A, 12-19, with Some supplementary references cited in the Reports, and the Petition for adoption of transmission standards for color television before the Federal Communications Commission, n.p., 1953, 17 v. illus., diagrs., tables. 28 cm. LC Control No.:54021386 Library of Congress Online Catalog The first black-and-white NTSC standard for broadcast was developed in 1941 and had no provision for color transmissions.

In 1953 a second modified version of the NTSC standard was adopted which allowed color broadcasting to be compatible with the existing stock of black-and-white receivers while maintaining the broadcast channel bandwidth already in use. NTSC was the first widely adopted broadcast color system. After over a half-century of use, the vast majority of over-the-air NTSC transmissions in the United States will be replaced with ATSC on June 12, 2009 and by August 31, 2011 in Canada.

History

The National Television System Committee was established in 1940 by the United States Federal Communications Commission (FCC) to resolve the conflicts that arose between companies over the introduction of a nationwide analog television system in the United States. In March 1941, the committee issued a technical standard for black-and-white television that built upon a 1936 recommendation made by the Radio Manufacturers Association (RMA). Technical advancements of the vestigial sideband technique allowed for the opportunity to increase the image resolution. The NTSC selected 525 scan lines as a compromise between RCA's 441–scan line standard (already being used by RCA's NBC TV network) and Philco's and DuMont's desire to increase the number of scan lines to between 605 and 800. The standard recommended a frame rate of 30 frames (images) per second, consisting of two interlaced fields per frame at 262.5 lines per field and 60 fields per second. Other standards in the final recommendation were an aspect ratio of 4:3, and frequency modulation (FM) for the sound signal (which was quite new at the time).

In January 1950, the Committee was reconstituted to standardize color television. In December 1953, it unanimously approved what is now called the NTSC color television standard (later defined as RS-170a). The "compatible color" standard retained full backward compatibility with existing black-and-white television sets. Color information was added to the black-and-white image by adding a color subcarrier of 4.5 × 455/572 MHz (approximately 3.58 MHz) to the video signal. To reduce interference between the chrominance signal and FM sound carrier required a slight reduction of the frame rate from 30 frames per second to 30/1.001 (very close to 29.97) frames per second, and changing the line frequency from 15,750 Hz to 15,734.26 Hz.