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A television transmitter is a transmitter that is used for terrestrial (over-the-air) television broadcasting.It is an electronic device that radiates radio waves that carry a video signal representing moving images, along with a synchronized audio channel, which is received by television receivers ('televisions' or 'TVs') belonging to a public audience, which display the image on a screen.
In TV receivers, the received radio frequency signal is converted to IF in tuner and then demodulated. The output of the demodulator consists of a VF and an aural signal which is in fact an FM subcarrier modulated by AF. (The subcarrier is 5.5 MHz in system B and 4.5 MHz in system M ) The aural signal and the VF are separated by a simple filter.
Plan showing VHF frequency ranges for ITU Systems. System A was the first formal broadcasting standard in the world. A European 41–68 MHz Band I television allocation was agreed at the 1947 ITU (International Telecommunication Union) conference in 1947, effectively "grandfathering in" the VHF allocation that has been used in Britain since 1936.
Analog TV systems global map, with System M in red. CCIR System M, [1] [2] [3] sometimes called 525–line, NTSC, NTSC-M, or CCIR-M, [4] [5] is the analog broadcast television system approved by the FCC (upon recommendation by the National Television System 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]
A few countries (Belgium, several of the Balkan states and Malta) use another variant of system B on UHF which is known as System H. System H is similar to system G but the lower (vestigial) side band is 500 kHz wider. This makes much better use of the 8.0 MHz channels of the UHF bands (though whether any system B/H televisions actually made ...
In March 2006, DVB decided to study options for an upgraded DVB-T standard. In June 2006, a formal study group named TM-T2 (Technical Module on Next Generation DVB-T) was established by the DVB Group to develop an advanced modulation scheme that could be adopted by a second generation digital terrestrial television standard, to be named DVB-T2.
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A broadcast transmitter is an electronic device which radiates radio waves modulated with information content intended to be received by the general public. Examples are a radio broadcasting transmitter which transmits audio (sound) to broadcast radio receivers (radios) owned by the public, or a television transmitter, which transmits moving images to television receivers (televisions).