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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 (unit), 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 (American system), although NTSC-J in Japan, also utilizing System M, uses 0 IRE for both black and blanking much like Systems B & G. So, while there is no difference between the black and the blanking levels in most systems, they differ by 50 mV in system M. (When defined in terms of voltage difference, 7.5 IRE units is almost eq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Composite Video Signal
Composite video, also known as CVBS (composite video baseband signal or color, video, blanking and sync), is an analog video format that combines image information—such as brightness (luminance), color (chrominance), and synchronization, into a single signal transmitted over one channel. It is most commonly used for standard-definition television, and is sometimes referred to as ''SD video''. The signal is typically carried on a yellow RCA connector, with separate connectors used for left and right audio channels. In professional equipment, a BNC connector is often used instead. Other connector types may appear in compact consumer devices like digital cameras. Composite video supports several line resolutions, including 405-line, 525-line, and 625-line interlaced formats. It exists in three major regional variants based on analog color encoding standards: NTSC, PAL, and SECAM. The same format can also be used to transmit monochrome (black-and-white) video. Signal component ... [...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 ... [...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 adopted by more than one hundred countries, either with PAL or SECAM colour. It is usually associated with CCIR System G for UHF broadcasts. System B was the first internationally accepted 625-line broadcasting standard in the world. A first 625-line system with a 8 MHz channel bandwidth was proposed at the CCIR Conference in Stockholm in July 1948 (based on 1946-48 studies in the Soviet Union by Mark KrivosheevOn the beginning of broadcast in 625-lines 60 year s ago, ''625'' magazine (in Russian). ). At a CCIR Geneva meeting in July 1950 Dr. Gerber (a Swiss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CCIR System G
CCIR System G, also known as the "Gerber Standard", is an analog broadcast television system used in sixty countries around the world for UHF channels. System G is generally associated with System B for VHF. At a CCIR Geneva meeting in July 1950, Dr. Gerber (a Swiss engineer), proposed a modified 625-lines system with a 7 MHz channel bandwidth (based on work by Telefunken and Walter Bruch). Known as the "Gerber Standard", it was initially approved for VHF broadcasts, and eventually adapted for UHF. Usually paired with PAL colour, it was also used with SECAM in Egypt, Iran and Saudi Arabia. Specifications Some of the important specs are listed below: * Frame rate: 25 Hz * Interlace: 2/1 * Field rate: 50 Hz * Lines/frame: 625 * Line rate: 15.625 kHzNot an independent value: 25 Hz×625=15.625 kHz * Visual bandwidth: 5 MHz * Vision modulation: AC3 negative * Preemphasis: 50 μs * Sound modulation: F3 * Sound offset: 5.5 MHz * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CCIR System M
CCIR System M, sometimes called 525–line, NTSC, NTSC-M, or CCIR-M, is the analog broadcast television system approved by the FCC (upon recommendation by the National Television System Committee - NTSC) for use in the United States since July 1, 1941, replacing the 441-line TV system introduced in 1938. It is also known as EIA standard 170. 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. 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 color encoding was normally used, with some exceptions: NTSC-J in Japan, PAL-M in Brazil and SECAM-M in Cambodia, Laos and Vietnam (see '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NTSC-J
NTSC-J or "System J" is the informal designation for the analogue television standard used in Japan. The system is based on the US NTSC ( NTSC-M) standard with minor differences. While NTSC-M is an official CCIR and FCCNational Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplementary references cited in the Reports, and the Petition for adoption of transmission standards for color television before the Federal Communications Commission, n.p., 1953], 17 v. illus., diagrs., tables. 28 cm. LC Control No.:5402138Library of Congress Online Catalog/ref> standard, NTSC-J or "System J" are a colloquial indicators. The system was introduced by NHK and NTV, with regular color broadcasts starting on September 10, 1960. NTSC-J was replaced by digital broadcasts in 44 of the country's 47 prefectures on 24 July 2011. Analogue broadcasting ended on 31 March 2012 in the three prefectures devastated by the 2011 Tōhoku earthquake ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television Technology
The technology of television has evolved since its early days using a mechanical system invented by Paul Gottlieb Nipkow in 1884. Every television system works on the scanning principle first implemented in the rotating disk scanner of Nipkow. This turns a two-dimensional image into a time series of signals that represent the brightness and color of each resolvable element of the picture. By repeating a two-dimensional image quickly enough, the impression of motion can be transmitted as well. For the receiving apparatus to reconstruct the image, synchronization information is included in the signal to allow proper placement of each line within the image and to identify when a complete image has been transmitted and a new image is to follow. While mechanically scanned systems were experimentally used, television as a mass medium was made practical by the development of electronic camera tubes and displays. By the turn of the 21st century, it was technically feasible to replace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
