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VF Bandwidth
In broadcast television systems, VF bandwidth, video bandwidth or more formally video frequency bandwidth is the range of frequencies between 0 and the highest frequency used to transmit a live television image. The maximum frequency can be found by multiplying three figures; the number of frames (images) per second, number of lines per frame and maximum number of sine In mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is oppo ... periods per line. In the table below number of frames per second, number of lines per frame and the video band width in different systems are shown.''Reference Data for Radio Engineers'', Howard W.Sams Co., Inc, , sec. 30, p. 33 References {{Analogue TV transmitter topics Television technology Video formats History of television ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadcast Television Systems
Broadcast television systems (or terrestrial television systems outside the US and Canada) are the encoding or formatting systems for the transmission and reception of terrestrial television signals. Analog television systems were standardized by the International Telecommunication Union in 1961, with each system designated by a letter ( A- N) in combination with the color standard used (NTSC, PAL or SECAM) - for example PAL-B, NTSC-M, etc.). These analog systems for TV broadcasting dominated until the 2010s. With the introduction of digital terrestrial television (DTT), they were replaced by four main systems in use around the world: ATSC, DVB, ISDB and DTMB. Analog television systems Every analog television system bar one began as a black-and-white system. Each country, faced with local political, technical, and economic issues, adopted a color television standard which was grafted onto an existing monochrome system such as CCIR System M, using gaps in the video spectrum ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bandwidth (signal Processing)
Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. It is typically measured in hertz, and depending on context, may specifically refer to ''passband bandwidth'' or ''baseband bandwidth''. Passband bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a band-pass filter, a communication channel, or a signal spectrum. Baseband bandwidth applies to a low-pass filter or baseband signal; the bandwidth is equal to its upper cutoff frequency. Bandwidth in hertz is a central concept in many fields, including electronics, information theory, digital communications, radio communications, signal processing, and spectroscopy and is one of the determinants of the capacity of a given communication channel. A key characteristic of bandwidth is that any band of a given width can carry the same amount of information, regardless of where that band is located in the frequency spectrum. For example, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Live Television
Live television is a television production broadcast in real-time, as events happen, in the present. In a secondary meaning, it may refer to streaming television over the Internet when content or programming is played continuously (not on demand). For example, the Pluto TV app has two categories for viewing: "Live TV" & "On Demand." On its website, Xfinity states "Watch TV series and top rated movies live and on demand with Xfinity Stream." In most cases live programming is not being recorded as it is shown on TV, but rather was not rehearsed or edited and is being shown only as it was recorded prior to being aired. Shows broadcast live include newscasts, morning shows, awards shows, sports programs, reality programs and, occasionally, episodes of scripted television series. Live television was more common until the late 1950s, when videotape technology was invented. Because of the prohibitive cost, adoption was slow, and some television shows remained live until the 1970s, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frame (video)
In filmmaking, video production, animation, and related fields, a frame is one of the many ''still images'' which compose the complete ''moving picture''. The term is derived from the historical development of film stock, in which the sequentially recorded single images look like a framed picture when examined individually. The term may also be used more generally as a noun or verb to refer to the edges of the image as seen in a camera viewfinder or projected on a screen. Thus, the camera operator can be said to keep a car in frame by panning with it as it speeds past. Overview When the moving picture is displayed, each frame is flashed on a screen for a short time (nowadays, usually 1/24, 1/25 or 1/30 of a second) and then immediately replaced by the next one. Persistence of vision blends the frames together, producing the illusion of a moving image. The frame is also sometimes used as a unit of time, so that a momentary event might be said to last six frames, the actual dura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line (video)
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems which, in turn, were replaced by flat panel displays of several types. Video systems vary in display resolution, aspect ratio, refresh rate, color capabilities and other qualities. Analog and digital variants exist and can be carried on a variety of media, including radio broadcast, magnetic tape, optical discs, computer files, and network streaming. History Analog video Video technology was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) television systems, but several new technologies for video display devices have since been invented. Video was originally exclusively a live technology. Charles Ginsburg led an Ampex research team developing one of the first practical video ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sine
In mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is opposite that angle to the length of the longest side of the triangle (the hypotenuse), and the cosine is the ratio of the length of the adjacent leg to that of the hypotenuse. For an angle \theta, the sine and cosine functions are denoted simply as \sin \theta and \cos \theta. More generally, the definitions of sine and cosine can be extended to any real value in terms of the lengths of certain line segments in a unit circle. More modern definitions express the sine and cosine as infinite series, or as the solutions of certain differential equations, allowing their extension to arbitrary positive and negative values and even to complex numbers. The sine and cosine functions are commonly used to model periodic phenomena such as sound and lig ... [...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] |
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] |
Video Formats
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems which, in turn, were replaced by flat panel displays of several types. Video systems vary in display resolution, aspect ratio, refresh rate, color capabilities and other qualities. Analog and digital variants exist and can be carried on a variety of media, including radio broadcast, magnetic tape, optical discs, computer files, and network streaming. History Analog video Video technology was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) television systems, but several new technologies for video display devices have since been invented. Video was originally exclusively a live technology. Charles Ginsburg led an Ampex research team developing one of the first practica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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