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Blanking Level
In video technology, blanking level is the level of the composite video signal during the front and back porches of the video signal. The composite video signal is actually the video information superimposed on blanking. The total level of the composite video signal (blanking + video) is 1000 mV. This level can also be given in IRE units such that the level difference reserved for video information is 100 IRE units. So white corresponds to 100 IRE units and blanking level corresponds to 0 IRE units. The level of black is 0 IRE units in the case of CCIR System B and CCIR System G (European systems) and 7.5 IRE units in the case of CCIR System M CCIR System M, sometimes called 525–line, monochrome NTSC or NTSC-M, is the analog broadcast television system approved by the FCC (upon recommendation by the National Television Systems Committee - NTSC) for use in the United States since ... (American system). So, while there is no difference between the black and the blanking lev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Composite Video Signal
Composite video is an analog video signal format that carries standard-definition video (typically at 525 lines or 625 lines) as a single channel. Video information is encoded on one channel, unlike the higher-quality S-Video (two channels) and the even higher-quality component video (three or more channels). In all of these video formats, audio is carried on a separate connection. Composite video is also known by the initials CVBS for composite video baseband signal or color, video, blanking and sync, or is simply referred to as ''SD video'' for the standard-definition television signal it conveys. There are three dominant variants of composite video signals, corresponding to the analog color system used: NTSC, PAL, and SECAM. Usually composite video is carried by a yellow RCA connector, but other connections are used in professional settings. Signal components A composite video signal combines, on one wire, the video information required to recreate a color ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IRE (unit)
The IRE unit is used in the measurement of composite video signals. Its name is derived from the initials of the Institute of Radio Engineers. A value of 100 IRE is defined to be +714 mV in an analog NTSC video signal. A value of 0 IRE corresponds to the voltage value of 0 mV, the signal value during the blanking period. The sync pulse is normally 40 IRE below this 0 IRE value, so the total range covered from peak to trough of an all white signal would be 140 IRE. Video signals use the "IRE" unit instead of DC voltages to describe levels and amplitudes. Based on a standard 1 Vpp NTSC composite-video signal that swings from -286 mV (sync tip) to +714 mV (peak video), a 140 IRE peak-to-peak convention is established. Thus, one NTSC IRE unit is 7.143 mV ( V or mV), where -40 IRE is equivalent to -285.7 mV, and +100 IRE is equivalent to +714.3 mV. 0 IRE is equivalent to 0 V. The black level is equivalent to 53.57 mV (7.5 IRE). The PAL video signal is slightly different in that it s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CCIR System B
CCIR System B (originally known as the "Gerber Standard") was the 625-line VHF analog broadcast television system which at its peak was the system used in most countries. It's usually associated with CCIR System G for UHF broadcasts. It is mostly replaced across Western Europe, part of Asia and Africa by digital broadcasting. Specifications The system was developed for VHF (also known as VHF-3) band (part of RF band lower than 300 MHz.) Some of the most important specs are listed below. A frame is the total picture. The frame rate is the number of pictures displayed in one second. But each frame is actually scanned twice interleaving odd and even lines. Each scan is known as a field (odd and even fields.) So field rate is twice the frame rate. In each frame there are 625 lines (or 312.5 lines in a field.) So line rate (line frequency) is 625 times the frame frequency or 625•25=15625 Hz. The video bandwidth is 5.0 MHz. The video signal modulates the carrier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CCIR System G
CCIR System G is an analog broadcast television system used in many countries. There are several systems in use and letter G is assigned for the European UHF system which is also used in the majority of Asian and African countries. (However some countries in Europe use different systems.) Specifications Some of the important specs are listed below.Reference Data for Radio Engineers, ITT Howard W.Sams Co., New York, 1977, section 30 A frame is the total picture. The frame rate is the number of pictures displayed in one second. But each frame is actually scanned twice interleaving odd and even lines. Each scan is known as a field (odd and even fields.) So field rate is twice the frame rate. In each frame there are 625 lines (or 312.5 lines in a field.) So line rate (line frequency) is 625 times the frame frequency or 625•25=15625 Hz. The RF parameters of the transmitted signal are exactly the same as those for System B which is used on the 7.0 MHz wide channels of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CCIR System M
CCIR System M, sometimes called 525–line, monochrome NTSC or NTSC-M, is the analog broadcast television system approved by the FCC (upon recommendation by the National Television Systems Committee - NTSC) for use in the United States since July 1, 1941, replacing the 441-line TV system introduced in 1938. System M displays a total of 525 lines of video (with 480 carrying visible image information) at 30 frames per second using 6 MHz spacing between channel numbers, and is used for both VHF and UHF channels. It was also adopted in most of the Americas and Caribbean, 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 on Cambodia and Vietnam (see ''Color standards'' section below). The letter M designation was attributed by the ITU on the 1961 Stockholm meeting (see ITU identif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television Technology
Large-screen television technology (colloquially big-screen TV) developed rapidly in the late 1990s and 2000s. Prior to the development of thin-screen technologies, rear-projection television was standard for larger displays, and jumbotron, a non-projection video display technology, was used at stadiums and concerts. Various thin-screen technologies are being developed, but only liquid crystal display (LCD), plasma display (PDP) and Digital Light Processing (DLP) have been publicly released. Recent technologies like organic light-emitting diode (OLED) as well as not-yet-released technologies like surface-conduction electron-emitter display (SED) or field emission display (FED) are in development to replace earlier flat-screen technologies in picture quality. Large-screen technologies have almost completely displaced cathode-ray tubes (CRT) in television sales due to the necessary bulkiness of cathode-ray tubes. The diagonal screen size of a CRT television is limited to abou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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