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CCIR System M, [1] [2] [3] sometimes called 525–line, monochrome NTSC, NTSC-M, or CCIR-M, [4] [5] is the analog broadcast television system approved by the FCC (upon recommendation by the National Television Systems Committee - NTSC) [6] for use in the United States since July 1, 1941, [7] [8] replacing the 441-line TV system introduced in 1938. [8] System M comprises a total of 525 interlaced lines of video, of which 486 contain the image information, at 30 frames per second. Video is amplitude modulated and audio is frequency modulated, with a total bandwidth of 6 MHz for each channel, including a guard band. [9]
It was also adopted in the Americas and Caribbean; Myanmar, Philippines, South Korea, Taiwan and Japan (here with minor differences, informally referred to as System J). System M doesn't specify a color system, but NTSC (NTSC-M) was normally used, with some exceptions: NTSC-J in Japan, PAL-M in Brazil and SECAM-M in Cambodia, Laos and Vietnam (see Color standards section below).
The letter M designation was attributed by the ITU at the 1961 Stockholm meeting (see ITU identification scheme). [10]
In 1965, Thailand decided to replace System M with 625-line CCIR System B which started in 1967 and adopted PAL in the same year. [11]
Since 2015, System M is being replaced by digital broadcasting, in countries such as the Americas, Japan, South Korea, Taiwan and the Philippines.
Some of the important specifications for System M are listed below: [12]
Strictly speaking, System M does not designate how color is transmitted. However, in nearly every System M country NTSC is used for color television. This combination is called NTSC-M, but usually simply referred to as "NTSC", because of the relative lack of importance of black-and-white television. In NTSC-M and Japan's NTSC-J, the frame rate is offset slightly, becoming 30⁄1.001 frames per second, usually labeled as the rounded number 29.97.
The main exception to System M's being paired with NTSC color is Brazil, where PAL color is used instead, resulting in the PAL-M combination unique to that country. It is monochrome-compatible with other System M countries, but not compatible with other PAL countries, which use 625-line based systems.
Between 1970 and 1991 a variation of the SECAM color system, known as SECAM-M, was used in Cambodia, [13] Laos, and Vietnam (Hanoi and other northern cities).
This article needs additional citations for
verification. (July 2022) |
CCIR System M, [1] [2] [3] sometimes called 525–line, monochrome NTSC, NTSC-M, or CCIR-M, [4] [5] is the analog broadcast television system approved by the FCC (upon recommendation by the National Television Systems Committee - NTSC) [6] for use in the United States since July 1, 1941, [7] [8] replacing the 441-line TV system introduced in 1938. [8] System M comprises a total of 525 interlaced lines of video, of which 486 contain the image information, at 30 frames per second. Video is amplitude modulated and audio is frequency modulated, with a total bandwidth of 6 MHz for each channel, including a guard band. [9]
It was also adopted in the Americas and Caribbean; Myanmar, Philippines, South Korea, Taiwan and Japan (here with minor differences, informally referred to as System J). System M doesn't specify a color system, but NTSC (NTSC-M) was normally used, with some exceptions: NTSC-J in Japan, PAL-M in Brazil and SECAM-M in Cambodia, Laos and Vietnam (see Color standards section below).
The letter M designation was attributed by the ITU at the 1961 Stockholm meeting (see ITU identification scheme). [10]
In 1965, Thailand decided to replace System M with 625-line CCIR System B which started in 1967 and adopted PAL in the same year. [11]
Since 2015, System M is being replaced by digital broadcasting, in countries such as the Americas, Japan, South Korea, Taiwan and the Philippines.
Some of the important specifications for System M are listed below: [12]
Strictly speaking, System M does not designate how color is transmitted. However, in nearly every System M country NTSC is used for color television. This combination is called NTSC-M, but usually simply referred to as "NTSC", because of the relative lack of importance of black-and-white television. In NTSC-M and Japan's NTSC-J, the frame rate is offset slightly, becoming 30⁄1.001 frames per second, usually labeled as the rounded number 29.97.
The main exception to System M's being paired with NTSC color is Brazil, where PAL color is used instead, resulting in the PAL-M combination unique to that country. It is monochrome-compatible with other System M countries, but not compatible with other PAL countries, which use 625-line based systems.
Between 1970 and 1991 a variation of the SECAM color system, known as SECAM-M, was used in Cambodia, [13] Laos, and Vietnam (Hanoi and other northern cities).