375-line television system

In Italy 375-line television transmissions were undertaken by Arturo Castellani^[8][9][10] in 1937,^[11] with daily broadcasts from Rome, between 6pm and 9:30pm on 6.9 meters (43.45 MHz) with a power of 2 kW.

In the spring of 1940, CBS staff engineer Peter Goldmark devised a system for color television, hoping to gain advantage regarding NBC and its black-and-white RCA system.^[12][13] The new system proposed by CBS was based on field sequential color and incompatible with existing sets^[14] but "gave brilliant and stable colors", while NBC developed a black and white compatible color TV system that was "crude and unstable but compatible".^[15]

After some tests with different line counts, on September 2, 1941, CBS announces a 375-line, 60 color frames per second system, requiring a horizontal scanning rate of 22,500 lines per second, and a vertical scanning rate of 120 fields per second (interlaced, giving a combined color picture frequency of 20 frames per second).^[13][16][17] The system was tested from CBS station WCBW New York, on June 1, 1941.^[18]

In 1945 CBS demonstrates color broadcast using test equipment and a 10 MHz bandwidth UHF channel.^[13] Later developments use higher line counts (525-line with 144 fields/second using 10 MHz video bandwidth and 441-line with 144 fields/second using 4 MHz video bandwidth are proposed in 1946), but system operation (field sequential, using a high bandwidth UHF channel) remained similar the 375-line tests.^[13]

Eventually it was shown to the general public on January 12, 1950, as the 405-line Field-Sequential Color System (FSC).^[19] The vertical resolution was 77% of monochrome, and the horizontal resolution was 54% of monochrome.^[20] The Federal Communications Commission adopted it on October 11, 1950, as the standard for color television in the United States, but it was later withdrawn.^[21]

The concept was revived by NASA in 1969 for the Apollo color TV cameras.^[14]