Analog broadcast television system
Analog TV systems global map, with System M in red.
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, adopting PAL at the same time.[ 11]
Since 2015, System M is being replaced by digital broadcasting , in countries such as the Americas, Japan, South Korea, Taiwan and the Philippines.
^ Korea Electronics Association (1991). Journal of Korean Electronics (PDF) .
^ Alonso, Rodney Martínez; Pupo, Ernesto Fontes; Pan, Changyong (June 10, 2015). "Co-channel and adjacent channel interference in DTMB with 6MHz channel bandwidth". 2015 IEEE International Symposium on Broadband Multimedia Systems and Broadcasting . pp. 1–5. doi :10.1109/BMSB.2015.7177274 . ISBN 978-1-4799-5865-8 . S2CID 11038252 – via IEEE Xplore.
^ "C.C.I.R - Documents of the Xlth Plenary Assembly Oslo, 1966" (PDF) .
^ Pupo, Ernesto Fontes; Alvarez, Rufino Cabrera; García, Alejandro González; Hernández, Reinier Díaz (October 10, 2020). "Protection ratios and overload thresholds between 700 MHz FDD-LTE and analog/digital terrestrial television" . 2020 IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB) . pp. 1–5. doi :10.1109/BMSB49480.2020.9379925 . ISBN 978-1-7281-5784-9 . S2CID 232373635 – via IEEE Xplore.
^ Odiaga, Martínez; Joussef, Hansel; Medina, Yarlequé; Augusto, Manuel (November 10, 2016). "Interference between UHF analog/digital television and LTE APT 700 MHz band: A field evaluation" . 2016 8th IEEE Latin-American Conference on Communications (LATINCOM) . pp. 1–5. doi :10.1109/LATINCOM.2016.7811615 . ISBN 978-1-5090-5137-3 . S2CID 11567258 – via IEEE Xplore.
^ Pursell, Carroll (April 30, 2008). A Companion to American Technology . John Wiley & Sons. ISBN 9780470695333 – via Google Books.
^ Herbert, Stephen (June 21, 2004). A History of Early Television . Taylor & Francis. ISBN 9780415326681 – via Google Books.
^ a b Meadow, Charles T. (February 11, 2002). Making Connections: Communication through the Ages . Scarecrow Press. ISBN 9781461706915 – via Google Books.
^ Rova, Andy (February 22, 2005). NTSC: Nice Technology, Super Color .
^ Final acts of the European Broadcasting Conference in the VHF and UHF bands. Stockholm, 1961.
^ "The Project of Nationwide Television Broadcasting Network in Thailand" (PDF) . Overseas Technical Cooperation Agency, Government of Japan. January 1967. p. 234. Retrieved 4 March 2024 .