National Television System Committee

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 broadcast to consumer televisions. The NTSC compromised between RCA's desire to keep a 441–scan line standard (which was already being used by RCA's NBC TV network) and Philco's desire to increase the number of scan lines to between 605 and 800: A 525-line transmission standard was selected. Other technical standards in the final recommendation were a frame rate (image rate) of 30 frames per second consisting of two interlaced fields per frame (2:1 interlacing) at 262.5 lines per field or 60 fields per second, along with 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 simply the NTSC color television standard (later defined as RS-170a). The updated standard retained full backwards compatibility ("compatible color") with older 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. In order to minimize interference between the chrominance signal and FM sound carrier, the addition of the color subcarrier also 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.

The FCC had briefly approved a different color television standard, starting in October 1950, which was developed by CBS.[2] However, this standard was incompatible with black-and-white broadcasts. It used a rotating color wheel (a technique re-used in the first DLP projectors developed in the late 1980s), reduced the number of scan lines from 525 to 405, and increased the field rate from 60 to 144 (but had an effective frame rate of only 24 frames a second). Legal action by rival RCA kept commercial use of the system off the air until June 1951, and regular broadcasts only lasted a few months before manufacture of all color television sets was banned by the Office of Defense Mobilization (ODM) in October, ostensibly due to the Korean War.[3] CBS rescinded its system in March 1953,[4] and the FCC replaced it on December 17, 1953 with the NTSC color standard, which was cooperatively developed by several companies (including RCA and Philco).[5] The first publicly announced network TV broadcast of a program using the NTSC "compatible color" system was an episode of NBC's Kukla, Fran and Ollie on August 30, 1953, although it was viewable in color only at the network's headquarters.[6] The first nationwide view of NTSC color came on the following January 1 with the coast-to-coast broadcast of the Tournament of Roses Parade, viewable on prototype color receivers at special presentations across the country.

The first color NTSC television camera was the RCA TK-40, used for experimental broadcasts in 1953; an improved version, the TK-40A, introduced in March 1954, was the first commercially available color TV camera. It was replaced later that year by an improved version, the TK-41, which became the standard camera used throughout much of the 1960s.

The NTSC standard has been adopted by other countries, including most of the Americas and Japan. With the advent of digital television, analog broadcasts are being phased out. Most NTSC broadcasters are mandated by the FCC to shut down in the United States on February 17, 2009 (low power, class A and translators are not immediately affected. A cut-off date for those stations is to be determined).