Television ( TV ) is a telecommunication medium used to transmit motion pictures in monochrome (black and white), or color, and in two or three dimensions and sounds. The term may refer to a television set, television program ("TV show"), or television transmission medium. Television is a mass media for advertising, entertainment, and news.
Television became available in rough experimental form in the late 1920s, but it will still be several years before new technology will be marketed to consumers. After World War II, black and white TV broadcasting became popular in the United States and Britain, and television became commonplace in homes, businesses and institutions. During the 1950s, television was the primary medium for influencing public opinion. In the mid-1960s, color broadcasting was introduced in the US and most other developed countries. The availability of various types of archive storage media such as Betamax, VHS tapes, local disks, DVDs, flash drives, high definition Blu-ray Discs, and digital cloud recorders have enabled viewers to watch pre-recorded material - like movies-- at home with schedules their own time. Due to various reasons, especially the convenience of remote retrieval, television storage and video programming are now happening in the cloud. At the end of the first decade of the 2000s, digital television transmissions greatly increased in popularity. Other developments are the displacement of standard definition television (SDTV) (576i, with 576 interlaced and 480i resolution lines) to high definition television (HDTV), which gives a much higher resolution. HDTV can be transmitted in various formats: 1080p, 1080i and 720p. Since 2010, with the invention of smart television, Internet television has increased the availability of television programs and movies over the internet through streaming video services such as Netflix, Amazon Video, iPlayer, Hulu, Roku and Chromecast.
In 2013, 79% of households in the world have televisions. The replacement of the initial high voltage cathode ray tube display (CRT) displays with a compact, energy-efficient, flat panel alternative technology such as LCDs (both neon-backlit and LED), OLED displays, and plasma screens are hardware. a revolution that began with a computer monitor in the late 1990s. Most TV sets sold in the 2000s are flat panels, especially LEDs. Large manufacturers announced the discontinuation of CRTs, DLPs, plasma, and even neon-backlit LCDs in the mid-2010s. In the near future, LEDs are expected to be gradually replaced by OLEDs. Also, major manufacturers have announced that they will further produce smart TV in the mid-2010s. Smart TV with integrated Internet and Web 2.0 functions became the dominant form of television in the late 2010s.
Television signals are initially distributed only as terrestrial television using high-frequency radio transmitters to broadcast signals to individual television receivers. Or television signals are distributed by coaxial or fiber optic cables, satellite systems and, since 2000 via the Internet. Until the early 2000s, this was transmitted as an analog signal, but the transition to digital television was expected to be completed worldwide in the late 2010s. A standard television set consists of several internal electronic circuits, including a tuner for receiving and decoding broadcast signals. A visual display device that does not have a tuner properly is called a video monitor rather than a television.
Video Television
Etymology
The word television comes from Ancient Greece ???? (ÃÆ'¨le) , which means 'remote', and Latin visio , meaning 'scenery'. The first documented use of this term dates from 1900, when Russian scientist Constantin Perskyi used it in a paper he presented in French at the First International Electrical Congress, which took place from 18 to 25 August 1900 during the International World Fair in Paris. The Anglicised version of this term was first proved in 1907, while still "... a theoretical system for transmitting moving images over telegraph or telephone cord". It "... was formed in English or borrowed from a vision tÃÆ'Ã… © lÃÆ'Ã… © lÃÆ'Â ©. France." In the 19th and early 20th centuries, "... another proposal for the name of hypothetical technology for sending remote images was telephote (1880) and televista (1904)." The abbreviation "TV" originated from 1948. The use of this term means "television date" originated from 1941. The use of this term means "television as a medium" originated from 1927. The term "television" slang is more common in England. The term "tube" or "tube boob" tube refers to the large cathode ray tube used on most TVs until the appearance of a flat-screen TV. The other slang term for TV is "idiot box".
Maps Television
History
Mechanical
Facsimile transmission systems for photographs still pioneered mechanical image scanning methods in the early 19th century. Alexander Bain introduced the facsimile machine between 1843 and 1846. Frederick Bakewell demonstrated a laboratory version of work in 1851. Willoughby Smith discovered the photoconductivity of the selenium element in 1873. As a 23-year-old German student, Paul Julius Gottlieb Nipkow proposed and patented the Nipkow disk in 1884 This is a rotating disk with a spiral pattern of holes in it, so that each hole scans the image line. Although he never built a working model of the system, the variations of Nipkow's "image rasterizer" became very common. Constantin Perskyi has created the word television in a paper read out for the International Electric Congress at the International World Fair in Paris on August 24, 1900. The Perskyi paper reviews the existing electromechanical technology, mentioning the work of Nipkow and others.. However, it was not until 1907 that the development of amplification tube technology by Lee de Forest and Arthur Korn, among others, made the design practical.
The first demonstration of the direct transmission of images was by Georges Rignoux and A. Fournier in Paris in 1909. A 64 selenium cell matrix, individually transferred to a mechanical commutator, functions as an electronic retina. Inside the receiver, a Kerr cell modulates light and a series of various slanted mirrors attached to the edges of the rotating disk that scan the modulated file to the display screen. Separate circuit set up synchronization. The 8x8 pixel resolution in this proof-of-concept demonstration is just enough to clearly transmit the letters of the individual alphabet. The updated image is sent "several times" every second. In 1921 Edouard Belin sent the first image through radio waves with his belinography.
In 1911, Boris Rosing and his student Vladimir Zworykin created a system that uses a mechanical mirror-drum scanner to transmit, in Zworykin's words, a "very rough image" on the cable to a "Braun tube" (cathode ray tube or "CRT ") in the recipient. Moving images is not possible because, in the scanner: "insufficient sensitivity and selenium cells are very laggy".
In the 1920s, when amplification made television practical, Scottish inventor John Logie Baird used the Nipkow disc in his prototype video system. On March 25, 1925, Baird gave the first public demonstration of the silhouette image being broadcast, at Selfridge's Department Store in London. Since the human face has inadequate contrast to appear in its primitive system, it broadcasts a ventriloquist puppet named "Stooky Bill", whose face is painted to have a higher contrast, speaks and moves. On January 26, 1926, he demonstrated the transmission of a radio-driven face image. This is widely regarded as the first television demonstration. His subject is Baird's business partner, Oliver Hutchinson. The Baird system uses Nipkow's disk to scan images and display them. The bright light that shines through the rotating Nipkow disk with the lens projects the bright spot of light that sweeps the subject. The photoelectric tube selenium detects the reflected light from the subject and converts it into a proportional electrical signal. These are transmitted by AM radio waves to the receiver, where the video signal is applied to the fluorescent light behind the second Nipkow disk that is synchronized with the first. The brightness of the fluorescent lamp varies in proportion to the brightness of each point on the image. As each hole in the disk passes, a line of image scanning is reproduced. Baird's disk has 30 holes, producing images with only 30 scanning lines, enough to recognize human faces. In 1927, Baird sent signals over 438 miles (705 km) from the phone line between London and Glasgow.
In 1928, the company Baird (Baird Television Development Company/Cinema Television) broadcasted the first transatlantic television signal, between London and New York, and the first transmission to the ship. In 1929, he became involved in the first experimental mechanical television service in Germany. In November of the same year, Baird and Bernard Natan of PathÃÆ'Â © founded the first television company in France, TÃÆ'Ã… © lÃÆ'Â Â © vision-Baird-Natan. In 1931, he made the first outdoor long-distance broadcast, from The Derby. In 1932, he demonstrated ultra-short wave television. Baird's mechanical system reached a peak of 240-line resolution on BBC television broadcasts in 1936, although the mechanical system did not scan the television scene directly. Instead the 17.5mm film was shot, quickly developed and then scanned when the film was still wet.
The American inventor, Charles Francis Jenkins, also pioneered television. He published an article on "Motion Pictures by Wireless" in 1913, but it was not until December 1923 that he sent a moving silhouette image to witnesses; and on June 13, 1925, he publicly demonstrated the synchronized silhouette transmission. In 1925 Jenkins used the Nipkow disc and sent a silhouette image of a moving toy windmill, over a distance of five miles, from a naval radio station in Maryland to his laboratory in Washington, DC, using a lens disc scanner with 48- line resolution. He was granted US Pat. 1.544.156 (Sending Image via Wireless) on June 30, 1925 (filed March 13, 1922).
Herbert E. Ives and Frank Gray of Bell Telephone Laboratories gave a dramatic demonstration of the mechanical television on April 7, 1927. Their reflective television system included a small and large viewing screen. The small receiver has a width of 2 inches with a 2.5 inch high screen. The large receiver has a 24 inch screen with a height of 30 inches. Both sets are capable of reproducing fairly accurate, monochromatic, and moving images. Along with the picture, the set receives a synced sound. The system transmits images through two lines: first, a copper wire link from Washington to New York City, then a radio link from Whippany, New Jersey. Comparing the two transmission methods, viewers noted there was no difference in quality. Subjects of the broadcast include Trade Minister Herbert Hoover. A point-flying scanning light illuminates these subjects. The scanner that generated the file has a 50-aperture disk. The disk rotates at a rate of 18 frames per second, capturing one frame approximately every 56 milliseconds. (Today's systems typically deliver 30 or 60 frames per second, or one frame every 33.3 or 16.7 milliseconds each.) Television historian Albert Abramson underlines the significance of Bell Labs demonstration: "It was actually the best demonstration of a mechanical television system that never existed made for now.It will be a few years before any other system can even start comparing it with image quality. "
In 1928, WRGB, then W2XB, started as the world's first television station. This is broadcast from the General Electric facility in Schenectady, NY. It's popularly known as "WGY Television". Meanwhile, in the Soviet Union, LÃÆ' Â © on Theremin has developed a drum-based television, beginning with 16 lines of resolution in 1925, then 32 lines and finally 64 using interlacing in 1926. As part of his thesis, on May 7, 1926, he transmitted electrically, and then projected, the image moves almost simultaneously on a five-foot square screen. In 1927 he achieved a drawing of 100 lines, a resolution not exceeded by May 1932 by RCA, with 120 lines. On December 25, 1926, Kenjiro Takayanagi demonstrated a 40-line television system using a Nipkow scanner disk and CRT screen at Hamamatsu Industrial High School in Japan. The prototype is still on display at Takayanagi Memorial Museum at Shizuoka University, Hamamatsu Campus. His research in creating a production model was stopped by the United States after Japan lost World War II.
Since only a number of holes can be made in the disk, and disks outside a certain diameter become impractical, the image resolution on the television broadcast is relatively low, ranging from about 30 lines to 120 or more. Nevertheless, the image quality of the 30-line transmission continued to increase with technical progress, and in 1933 the British broadcasting system using Baird was very clear. Some systems start into the 200-line area also airs. Two of them are the Compagnie des Compteurs (CDC) 180-line system installed in Paris in 1935, and the 180-line Peck Television Corp system began in 1935 at the VE9AK station in Montreal. The advancement of all electronic television (including the exposure of images and other camera tubes and cathode ray tubes for reproduction) marks the beginning of the end for a mechanical system as the dominant form of television. Mechanical television, despite its low image quality and generally smaller images, will remain the premier television technology until the 1930s. The last mechanical television broadcast ended in 1939 at stations run by a handful of public universities in the United States.
Electronics
In 1897, the British physicist J. J. Thomson was able, in his three famous experiments, to deflect cathode rays, the fundamental function of modern cathode ray tubes (CRTs). The earliest version of the CRT was invented by the German physicist Ferdinand Braun in 1897 and is also known as the "Braun" tube. It is a cold cathode diode, modified Crookes tube, with a phosphor coated screen. In 1906, German Max Dieckmann and Gustav Glage produced raster images for the first time in CRT. In 1907, Russian scientist Boris Rosing used a CRT on the receiving end of an experimental video signal to form an image. He managed to display a simple geometric shape to the screen.
In 1908 Alan Archibald Campbell-Swinton, a fellow of the Royal Society (UK), published a letter in the scientific journal Nature where he describes how "distant electrical vision" can be achieved using cathode ray tubes, or Braun tube, both as a transmitting and receiving device, He expanded his vision in a speech given in London in 1911 and reported in The Times and Journal of the RÃ © ntgen Society. In a letter to Nature published in October 1926, Campbell-Swinton also announced the results of some of the "less successful experiments" he did with G. M. Minchin and J. C. M. Stanton. They have attempted to generate electrical signals by projecting an image onto a metal-coated selenium plate that is simultaneously scanned by cathode rays. This experiment was conducted before March 1914, when Minchin died, but was subsequently repeated by two different teams in 1937, by H. Miller and J. W. Strange of EMI, and by H. Iams and A. Rose of RCA. Both teams managed to transmit a "very dim" image with the original Campbell-Swinton-coated selenium plate. Although others have experimented with using cathode ray tubes as receivers, the concept of using one as a transmitter is novel. The first cathode ray tube using a hot cathode was developed by John B. Johnson (who gave his name to Johnson's voice term) and Harry Weiner Weinhart of Western Electric, and became a commercial product in 1922.
In 1926, Hungarian engineers KÃÆ'¡lmÃÆ'¡n Tihanyi designed a television system that uses full electronic scanning and displays the elements and uses the principle of "charge storage" in a scanning tube (or "camera"). The low sensitivity to light issue resulted in a low electrical output of the transmission or "camera" of the tube to be completed with the introduction of cost storage technology by KÃÆ'¡lmÃÆ'¡n Tihanyi started in 1924. The solution was an accumulated camera tube and storing electrical charge ("electron photograph ") inside the tube throughout each scan cycle. This device was first described in a patent application filed in Hungary in March 1926 for a television system dubbed "Radioskop". After further improvements included in the patent application of 1928, Tihanyi's patent was void in England in 1930, so he applied for a patent in the United States. Although his breakthrough will be incorporated into the "RCA iconic" design of RCA in 1931, the US patent for the Tihanyi transmitter tube will not be delivered until May 1939. A patent for the receiver tube was granted in October. Both patents have been purchased by RCA before their approval. Cost storage remains a basic principle in the design of imaging devices for television to this day. On December 25, 1926, at Hamamatsu Industrial College in Japan, Japanese inventor Kenjiro Takayanagi demonstrated a 40-line TV system that uses CRT screens. This is the first working example of a fully electronic television receiver. Takayanagi did not file a patent application.
On September 7, 1927, the inventor of the picture shooter tube camera Philo Farnsworth sent his first, simple straight line, in his laboratory at 202 Green Street in San Francisco. On September 3, 1928, Farnsworth had developed enough systems to hold demonstrations for the press. This is widely regarded as the first electronic television demonstration. In 1929, the system was further enhanced by the removal of motor generators, so its television system now lacks mechanical components. That year, Farnsworth sent the first live human image to his system, including a three and a half inch image of his wife Elma ("Pem") with his eyes closed (probably because bright lighting is needed).
Meanwhile, Vladimir Zworykin also experimented with cathode ray tubes to create and display images. While working for Westinghouse Electric in 1923, he began to develop electronic camera tubes. But in the 1925 demonstration, the image was dim, had low contrast, and the definition was bad, and stationary. Zworykin's imaging tube never goes beyond the lab stage. But RCA, which acquired Westinghouse patent, asserted that the patent for Farnsworth 1927 image aberration was written so widely that it excludes other electronic imaging devices. So RCA, on the basis of Zworykin's patent application of 1923, filed a patent interference lawsuit against Farnsworth. The US Patent Office tester disagrees in the 1935 decision, finding priority discovery for Farnsworth against Zworykin. Farnsworth claims that Zworykin's 1923 system will not be able to produce electrical images of its type to challenge its patents. Zworykin received a patent in 1928 for a color transmission version of his patent application in 1923; he also shared the original application in 1931. Zworykin was unable or unwilling to introduce evidence of its tube-working model based on its patent application in 1923. In September 1939, after losing an appeal in court, and determined to move forward with manufacturing of commercial television equipment, RCA agrees to pay Farnsworth US $ 1 million over a period of ten years, in addition to license payments, to use the patent.
In 1933, RCA introduced a better camera tube that relies on the principle of Tihanyi charge storage. Dubbed "Iconoscope" by Zworykin, the new tube has a light sensitivity of about 75,000 lux, and thus is claimed to be much more sensitive than Farnsworth's image aberration. However, Farnsworth has overcome its power problem with its Image Dissector through the discovery of a truly unique "multipactor" device that began work in 1930, and was demonstrated in 1931. This small tube can amplify the reported signal to the 60th power or better. and show great promise in all areas of electronics. Unfortunately, the problem with multipactor is that it breaks at an unsatisfactory rate.
At the Berlin Radio Show in August 1931, Manfred von Ardenne gave a public demonstration of the television system using CRTs for transmission and reception. However, Ardenne did not develop camera tubes, using CRTs as a point-fly scanner to scan slides and movies. Philo Farnsworth gave the world's first public demonstration of an all-round electronic television system, using live cameras, at the Franklin Institute of Philadelphia on August 25, 1934, and for the next ten days. Mexican inventor Guillermo GonzÃÆ'¡lez Camarena also played an important role in early TV. His experiments with TV (known as telectroescopÃÆ'a initially) began in 1931 and led to a patent for the color television "trichromatic field sequential system" in 1940. In England, the EMI engineering team led by Isaac Shoenberg was applied in 1932 for a patent for a new device which they named "Emitron", which formed the heart of the camera they designed for the BBC. On November 2, 1936, a 405-line broadcast service that used Emitron began in studio studios at Alexandra Palace, and was transmitted from a specially built pole above one of the Victorian-style towers. It alternated for a short time with Baird's mechanical system in an adjacent studio, but was more reliable and superior. This is the world's first regular "high-definition" television service.
Native American Iconoscope is noisy, has a high signal-distortion ratio, and ultimately gives disappointing results, especially when compared to high-definition mechanical scanning systems that are then available. The EMI team, under the supervision of Isaac Shoenberg, analyzed how the iconoscope (or Emitron) produced an electronic signal and concluded that the actual efficiency was only about 5% of the theoretical maximum. They solved this problem by developing, and patenting in 1934, two new camera tubes dubbed the Emitron super and Emitron CPS. Super-Emitron is between ten and fifteen times more sensitive than the Emitron tube and original icons and, in some cases, this ratio is much larger. It was used for outside broadcasting by the BBC, for the first time, on the 1937 Armistice Day, when the general public was able to watch on television when the King laid a wreath in the Cenotaph. This is the first time anyone has broadcast a live street scene from a camera mounted on the roof of a neighboring building, as neither Farnsworth nor RCA will do the same until the 1939 New York World Expo.
On the other hand, in 1934, Zworykin shared several patents with the German licensing company, Telefunken. The "Iconoscope image" ("Supericononoscope" in Germany) is produced as a result of collaboration. This tube is essentially identical to the super-Emitron. The production and commercialization of the super-Emitron photo icons and images in Europe were unaffected by the patent war between Zworykin and Farnsworth, as Dieckmann and Hell had priorities in Germany for the discovery of dissecting images, after applying for a patent for them. i> Lichtelektrische BildzerlegerrÃÆ'¶hre fÃÆ'¼r Fernseher (Photoelectric Image Dissector Tube for Television ) in Germany in 1925, two years before Farnsworth did the same in the United States. Iconoscope images (Superoconoscopes) became the industry standard for public broadcasting in Europe from 1936 to 1960, when replaced by vidicon tubes and plumbicon. Indeed, it is representative of European traditions in electronic tubes that compete with American traditions represented by orthicons images. The German company Heimann produced the Supericonoscope for the 1936 Berlin Olympics, then Heimann also produced and marketed it from 1940 to 1955; finally the Dutch company Philips produced and commercialized the image and multiconographic iconography from 1952 to 1958.
American television broadcasting, at the time, consisted of various markets of varying sizes, each competing for programming and dominance with separate technology, until a deal was made and the standard was agreed upon in 1941. RCA, for example, uses only Iconoscopes in the New York area, but Farnsworth Image Dissectors in Philadelphia and San Francisco. In September 1939, RCA agreed to pay Farnsworth Television and Radio Corporation royalties over the next ten years to gain access to Farnsworth patents. With this historic agreement, RCA integrates many of the best things about Farnsworth Technology into their systems. In 1941, the United States implements 525-line television. Electrical engineer Benjamin Adler played an important role in the development of television.
The world's first 625-line television standard was designed in the Soviet Union in 1944 and became the national standard in 1946. The first broadcast in the 625-line standard took place in Moscow in 1948. The concept of 625 rows per frame was subsequently implemented in the European CCIR Standards. In 1936, KÃÆ'¡lmÃÆ'¡n Tihanyi described the principle of plasma screens, the first flat panel display system.
Color
The basic idea of ​​using three monochrome images to produce color images was tried immediately after the first black-and-white television was built. Although he did not provide practical details, among the earliest published proposals for television was one by Maurice Le Blanc, in 1880, for the color system, including the first mentioned in the television literature of line scanning and frames. Polish inventor Jan Szczepanik patented a color television system in 1897, using photoelectric selenium cells in transmitters and electromagnets that control oscillating mirrors and moving prisms in the receiver. But the system does not contain the means to analyze the color spectrum at the end of the transmission, and can not function as it describes it. Another inventor, Hovannes Adamian, also experimented with color television as early as 1907. The first color television project was claimed by him, and patented in Germany on March 31, 1908, patent No. 197183, then in England, on April 1, 1908, patent No 7219, in France (patent No. 390326) and in Russia in 1910 (patent No. 17912).
Scottish inventor John Logie Baird demonstrated the world's first color transmission on July 3, 1928, using a scan disc for transmission and receiving the tip with three spiral holes, each spiral with a different primary color filter; and three light sources at the receiving end, with the commutator to change their illumination. Baird also made the world's first color broadcast on February 4, 1938, sending a mechanically scanned 120-line image from Crystal Palace Baird's studio to a projection screen at the Dominion Theater in London. The mechanically scanned colored television was also demonstrated by Bell Laboratories in June 1929 using three complete photoelectric cell systems, amplifiers, light tubes, and color filters, with a series of mirrors to place on top of red, green, and blue images into one full-color image.
The first practical hybrid system was once again pioneered by John Logie Baird. In 1940 he openly demonstrated a color television that incorporated a traditional black-and-white screen with rotating colored discs. The device is very "deep", but is then upgraded with a light-colored folding mirror to a device that is entirely practical to resemble a large conventional console. However, Baird is unhappy with the design, and, since 1944, has commented to the British government committee that electronic devices will be completely better.
In 1939, Hungarian engineer Peter Carl Goldmark introduced a temporary electro-mechanical system on CBS, which contained the Iconoscope sensor. The CBS field sequence color system is partly mechanical, with discs made of red, blue, and green filters that rotate inside a television camera at 1,200 rpm, and the same dish rotates in sync in front of the cathode ray tube inside the receiving device.. This system was first shown to the Federal Communications Commission (FCC) on August 29, 1940, and shown to the press on September 4.
CBS started field color trials using the film as early as August 28, 1940, and a live camera on November 12th. NBC (owned by RCA) made the first color television field trials on February 20, 1941. CBS started a daily color-field test on June 1, 1941. This color system is not compatible with the existing black-and-white television set, and, since there is no set Color television is publicly available at the moment, viewing color field tests is limited to RCA and CBS engineers and invited press. The War Production Board suspended the manufacture of television and radio equipment for civilian use from April 22, 1942 to August 20, 1945, limiting any opportunity to introduce color television to the general public.
In early 1940, Baird began work on a complete electronic system which he called Telechrome. Early Telechrome devices used two electron guns aimed at both sides of the phosphor plate. The phosphor is patterned so that the electrons from the weapon just fall on one side of the pattern or the other. By using cyan and magenta phosphors, reasonable reasonable color images can be obtained. He also demonstrated the same system using monochrome signals to produce 3D images (called "stereoscopic" at the time). Demonstration on August 16, 1944 is the first example of a practical color television system. Working in Telechrome continues and plans are made to introduce a three-weapon version for full color. However, Baird's sudden death in 1946 ended the development of the Telechrome system. Similar concepts were also common in the 1940s and 1950s, differing mainly in the way they recombined the colors produced by the three weapons. The Geer Tube is similar to the Baird concept, but uses small pyramids with phosphorus deposited on its outer face, rather than the Baird 3D pattern on a flat surface. The Penetron uses three phosphor layers on top of each other and increases the beam's strength to reach the top layer when drawing those colors. Chromatron uses a set of focus cables to select colored phosphors arranged in vertical lines on the tube.
One of the major technical challenges in introducing color television broadcasting is the desire to save bandwidth, potentially three times that of existing black-and-white standards, and not to use excessive radio spectrum. In the United States, after conducting research, the National Television Systems Committee approved an electronic compatible color system developed by RCA, which encodes color information separately from brightness information and greatly reduces color information resolution to save bandwidth.. The brightness image remains compatible with the existing black-and-white television at a slightly reduced resolution, while color television can decode additional information in the signal and produce a limited-resolution color display. Higher black-and-white color image resolutions combine in the brain to produce high-resolution color images. The NTSC standard represents a major technical achievement.
Although all electronic colors were introduced in the US in 1953, high prices, and the scarcity of color programming, severely slowed its acceptance in the market. The first national broadcast (1954 Tournament of Roses Parade) occurred on January 1, 1954, but for the next ten years most of the network broadcasts, and almost all local programs, continued to be black and white. It was not until the mid-1960s that color sets began to sell in bulk, in part because of the 1965 color transition in which it was announced that more than half of all prime-time programming networks would be broadcast in fall colors. The first prime season of all colors came just one year later. In 1972, the latest dispute between the daytime network program was changed to color, generating the first full-colored networking season entirely.
The initial color set is a console model that stands on the floor or a table version almost as large and heavy; so in practice they keep anchored in one place. The introduction of the compact and lightweight GE Porta-Color in the spring of 1966 made viewing color television a more flexible and comfortable proposition. In 1972, sales of color sets eventually surpassed the sale of black and white sets. Color broadcasting in Europe was not standardized in the PAL format until the 1960s, and the broadcast did not begin until 1967. At this point many technical problems in the initial set had been done, and the spread of color sets in Europe was fast enough. In the mid-1970s, the only black-and-white broadcast stations were some high-profile UHF stations in small markets, and some low power repeater stations in smaller markets such as vacation spots. In 1979, even the latter had turned into color and, in the early 1980s, B & W has been driven into specialized markets, especially the use of low-power, small portable devices, or for use as a video monitor screen below. cost of consumer equipment. In the late 1980s even these areas switched to color sets.
Digital
Digital television (DTV) is an audio and video transmission with digitally processed and digitized signals, in contrast to fully analog signals and channels separated by analog television. Because digital TV data compression can support more than one program in the same channel bandwidth. This is an innovative service that represents the first significant evolution in television technology since color television in the 1950s. The roots of digital TV have been tied very closely to the availability of expensive and high-performing computers. It was not until the 1990s that digital TV became feasible.
In the mid-1980s, when Japanese consumer electronics companies advanced with the development of HDTV technology, the MUSE analog format proposed by NHK, a Japanese company, was seen as a pacesetter that threatened to overwhelm US electronics technology companies. By June 1990, the Japanese MUSE standard, based on analog systems, was at the forefront of more than 23 different technical concepts under consideration. Then, the American company, General Instrument, shows the feasibility of a digital television signal. This breakthrough is so important that the FCC is convinced to delay its decision on ATV standards until a digital-based standard can be developed.
In March 1990, when it became clear that digital standards were feasible, the FCC made a number of important decisions. First, the Commission states that the new ATV standard must be more than an enhanced analog signal, but capable of delivering the original HDTV signal with at least twice the resolution of an existing television image. (7) Then, to ensure that viewers who do not want to buy a new digital television can continue to receive conventional television broadcasts, it dictates that the new ATV standard should be capable of being "simulcast" on different channels. (8) The new ATV standard also enables new DTV signals to be based on completely new design principles. Although not in accordance with existing NTSC standards, the new DTV standard will be able to incorporate many improvements.
Final standards adopted by the FCC do not require a single standard to scan formats, aspect ratios, or resolution lines. This compromise resulted from a dispute between the consumer electronics industry (followed by several broadcasters) and the computer industry (followed by the film industry and some common interest groups) of which two scanning processes - interlaced or progressive - would be best suited for HDTV compatible display devices newer digital. Interlaced scanning, which has been specifically designed for older analog CRT display technology, scans even numbered lines first, then odd numbered. In fact, interlaced scanning can be seen as the first video compression model since it was partly designed in the 1940s to double the image resolution to surpass the limitations of broadcast television bandwidth. Another reason for its adoption is to limit wrinkles on initial CRT screens that phosphor-coated screens can only retain the image of an electron scanner scanner for a relatively short duration. However, interlaced scanning does not work as efficiently on newer display devices as Liquid-crystal (LCD), for example, which is more suitable for more frequent progressive refresh rates.
Progressive scanning, a format long adopted by the computer industry for computer screen monitors, scans each line in sequence, from top to bottom. Progressive scanning on the effect doubles the amount of data generated for each full screen displayed compared to the interlaced scan by painting the screen once in 1/60-second instead of two passes in 1/30-second. The computer industry argues that progressive scanning is superior because it does not "flicker" on the new standard of display devices by means of interlaced scanning. He also believes that progressive scanning enables easier connections with the Internet, and is cheaper to convert to interlaced formats than vice versa. The film industry also supports progressive scanning as it offers a more efficient way to convert programs that are filmed into digital format. For their part, the consumer electronics industry and broadcasters argue that interlaced scanning is the only technology that can deliver images of the highest quality then (and currently) feasible, that is, 1,080 lines per image and 1,920 pixels per line. Broadcasters also love interlaced scanning because large archives of interlaced programming do not match the progressive format. William F. Schreiber, who was director of the Advanced Television Research Program at the Massachusetts Institute of Technology from 1983 to retirement in 1990, thinks that the continuous advocacy of interlaced equipment comes from consumer electronics companies that are trying to regain their huge investments making interlaced technology.
The transition of digital television began in the late 2000s. All governments around the world set a deadline for analog cessation in the 2010s. Initially the adoption rate was low, because the first digital TV tuner was expensive. But soon, when the price of digital TV is decreasing, more and more households are turning to digital television. The transition is expected to be completed worldwide in mid to late 2010s.
Smart TV
The advent of digital television enabled innovations such as smart TV. A smart television, sometimes referred to as a connected TV or hybrid TV, is a television or set-top box with integrated Internet and Web 2.0 features, and is an example of convergence technology between computers, television sets and set-top boxes. In addition to the traditional functions of television sets and set-top boxes provided through traditional broadcast media, this device can also provide Internet TV, online interactive media, over-the-top content, and streaming media on demand, and home network access. This TV is equipped with an operating system.
Smart TV should not be equated with Internet TV, Internet Protocol television (IPTV) or with Web TV. Internet television refers to the reception of television content over the Internet rather than by traditional systems - terrestrial, cable and satellite (although the internet itself is accepted by this method). IPTV is one of the Internet television technology standards that appear to be used by television broadcasters. Web television (WebTV) is a term used for programs created by various companies and individuals to broadcast on Internet TV. The first patent was filed in 1994 (and extended the following year) for "smart" television systems, linked to data processing systems, via digital or analogue networks. In addition to connecting to a data network, a key point is its ability to automatically download the required software routines, according to user requests, and process their needs. The major TV producers have announced the production of smart TV only, for medium and high grade TV by 2015. Smart TV is expected to become the dominant form of television in the late 2010s.
3D
3D television conveys deep perceptions to viewers using techniques such as stereoscopic display, multi-display display, 2D-plus depth, or other forms of 3D viewing. Most modern 3D televisions use either an active 3D shutter system or a polarized 3D system, and some autostereoscopic without the need for glasses. 3D stereoscopic television was shown for the first time on August 10, 1928, by John Logie Baird at his firm place at 133 Long Acre, London. Baird pioneered various 3D television systems using electromechanical tube and cathode ray techniques. The first 3D TV was produced in 1935. The emergence of digital television in the 2000s greatly enhanced the 3D TV. Although 3D TV sets are popular enough to watch 3D home media such as on Blu-ray discs, 3D programming has largely failed to make a breakthrough with the public. Many 3D television channels beginning in early 2010 were closed in mid-2010. According to DisplaySearch 3D TV shipments reached 41.45 million units in 2012, compared to 24.14 in 2011 and 2.26 in 2010. By the end of 2013 , the number of 3D TV viewers is starting to decline.
Broadcast system
Terrestrial Television
Programming is broadcast by television stations, sometimes called "channels", because stations are licensed by their governments to broadcast only through channels assigned to television bands. At first, terrestrial broadcasting is the only way television can be widely distributed, and because of limited bandwidth, that is, there are only a small number of channels available, government regulation is the norm. In the US, the Federal Communications Commission (FCC) allows stations to broadcast advertisements starting July 1941, but requires a commitment to public service programming as a requirement for licensing. In contrast, the United Kingdom opted for a different route, charging television licensing fees to owners of television reception equipment to fund the British Broadcasting Corporation (BBC), which has a public service as part of its Royal Charter.
WRGB claims to be the world's oldest television station, tracing its roots to an experimental station set up on January 13, 1928, broadcasting from the General Electric plant in Schenectady, NY, under the summons of W2XB . It was popularly known as "WGY Television" after his brother's radio station. Then in 1928, General Electric started a second facility, this one in New York City, which has a W2XBS call letter and which is today known as WNBC. Both stations are experimental and have no regular programming, because the recipient is operated by engineers within the company. The rotating figure of the Felix the Cat puppet on the turntable is broadcast for 2 hours every day for several years as new technology is being tested by engineers. On November 2, 1936, the BBC began transmitting the world's first public regular high definition service from Victorian Alexandra Palace in north London. Because it claims to be the birthplace of TV broadcasting as we know it today.
With widespread adoption of wires throughout the United States in the 1970s and 80s, terrestrial television broadcasts declined; in 2013 it is estimated that about 7% of US households use antennas. A slight increase in usage begins around 2010 due to a shift to digital terrestrial television broadcasting, which offers pure image quality across a vast area, and offers an alternative to cable television (CATV) for cable cutters. All other countries around the world are also in the process of turning off analog terrestrial television or switching to digital terrestrial television.
Cable television
Cable television is a television program broadcasting system to pay customers through radio frequency (RF) signals transmitted via coaxial cable or light pulses through fiber optic cables. This contrasts with traditional terrestrial television, where television signals are transmitted over the air by radio waves and are received by television antennas attached to the television. In the 2000s, FM radio programs, high speed Internet, telephone service, and similar non-television services could also be provided through these cables. CATV abbreviation is often used for cable television. It originally stood for the Television Television Community or Television Antenna Community, from the origin of cable TV in 1948: in areas where airborne reception is limited by distance from transmitters or mountain areas, large "community antennas" are built, and cables run from them to their respective homes -something. The origins of cable broadcasting are even older as radio programming is distributed by cable in some European cities as far back as 1924. Cable television was formerly analog, but since the 2000s, all cable operators have switched to, or are in the process of switching. to, digital cable television.
Satellite Television
Satellite television is a system of providing television programs using broadcast signals broadcast from communications satellites. The signal is received through a remarkable parabolic reflector antenna usually referred to as a parabola and a low-noise block downconverter (LNB). The satellite receiver then translates the desired television program to be viewed on television. The receiver can be either an external set-top box, or a built-in television tuner. Satellite television provides a variety of channels and services, especially for geographic areas without terrestrial television or cable television.
The most common method of reception is live satellite television broadcast (DBSTV), also known as "direct to home" (DTH). In the DBSTV system, the signal is broadcast from a live broadcast satellite at the wavelength of K u and fully digital. Previous satellite TV systems use a system known as television to receive only. This system receives analog signals transmitted in the C-band spectrum of FSS type satellites, and requires the use of large disks. As a result, the system is dubbed a "big plate" system, and is more expensive and less popular.
Satellite television signals that are broadcast live are analog signals before and then digital signals, both of which require a compatible receiver. Digital signals may include high definition television (HDTV). Some transmission and free-to-air or free-to-view channels, while many other channels pay for television that requires subscriptions. In 1945, the English science fiction writer Arthur C. Clarke proposed a worldwide communication system that would function in the way of three satellites equally placed separately in Earth's orbit. It was published in the October 1945 issue of Wireless World magazine and won it the Stuart Ballantine Medal at the Franklin Institute in 1963.
The first satellite television signal from Europe to North America was transmitted via Telstar satellite across the Atlantic on July 23, 1962. Signals were received and broadcast in North American and European countries and watched over 100 million. Launched in 1962, the Relay 1 satellite was the first satellite to transmit television signals from the US to Japan. The first geosynchronous communications satellite, Syncom 2, was launched on July 26, 1963.
The world's first commercial communications satellite, called Intelsat I and dubbed "Early Bird", was launched into geosynchronous orbit on April 6, 1965. The first satellite satellite network, called Orbita, was made by the Soviet Union in October 1967, and based on the principle of using the Molniya satellite highly elliptical for re-broadcasting and transmitting television signals to ground downlink stations. The first North American commercial satellite carrying a television transmission was the Canadian geostationer Anik 1, launched on November 9, 1972. ATS-6, the world's first experimental and Direct Broadcast Satellite (DBS), was launched on May 30, 1974. at 860 MHz using modulation FM wideband and has two voice channels. Transmission is focused on the Indian subcontinent but researchers are able to receive signals in Western Europe using exciting home-made equipment on already used UHF television design techniques.
The first in a series of Soviet geostationary satellites to bring Direct-To-Home television, Ekran 1, was launched on October 26, 1976. It uses a 714 MHz UHF downlink frequency so transmission can be received with existing UHF television technology rather than microwave technology.
Internet television
Internet television (or online television) is the digital distribution of television content over the Internet compared to traditional systems such as terrestrial, cable and satellite, even though the Internet itself is accepted by terrestrial, cable or satellite methods. Internet television is a generic term that includes the delivery of television shows, and other video content, over the Internet by streaming video technology, usually by large traditional television broadcasters. Internet television should not be equated with Smart TV, IPTV or with Web TV. Smart television refers to a TV set that has a built-in operating system. Internet Protocol television (IPTV) is one of the Internet television technology standards that appear to be used by television broadcasters. Web television is a term used for programs created by various companies and individuals to broadcast on Internet TV.
Set
A television set, also called a television receiver, television, TV, TV or "television", is a device that combines tuners, screens, amplifiers, and speakers for the purpose of watching television and listening to audio components. Introduced in the late 1920s in mechanical form, television became a popular consumer product after World War II in electronic form, using cathode ray tubes. The addition of color to television broadcasts after 1953 further increased the popularity of television and outdoor antennas became a common feature of suburban homes. The ubiquitous television sets became a display device for media recorded in the 1970s, such as Betamax and VHS, allowing viewers to record TV shows and watch previously recorded movies. In the next few decades, TV is used to watch DVD and Blu-ray Discs movies and other content. The major TV manufacturers announced the termination of CRT, DLP, plasma and neon-backlit LCDs in the mid-2010s. Television since 2010s mostly use LEDs. LEDs are expected to be gradually replaced by OLEDs in the near future.
Display technology
Disk
The earliest systems used rotating disks to create and reproduce images. These usually have low resolution and screen size and never become popular in the community.
CRT
The cathode ray tube (CRT) is a vacuum tube containing one or more electron guns (the source of electrons or electron transmitters) and the fluorescent screen used to view the image. It has the means to accelerate and deflect the electron beam onto the screen to create an image. The images can represent the form of electric waves (oscilloscopes), images (television, computer monitor), radar or other targets. CRTs use large evacuated glass envelopes, inside (ie from the front of the front screen to the back), quite heavy, and relatively fragile. As a security issue, faces are usually made of heavy lead glass so they are very resistant to breaking and block most X-ray emissions, especially if CRTs are used in consumer products.
On television sets and computer monitors, the entire front of the tube is scanned repeatedly and systematically in a fixed pattern called a raster. An image is generated by controlling the intensity of each of the three electron beams, one for each additional primary color (red, green, and blue) with the video signal as a reference. In all modern CRT monitors and televisions, the beam is bent by the magnetic deflection, the different magnetic fields generated by the windings and driven by electronic circuits around the neck of the tube, although electrostatic deflection is usually used in an oscilloscope. , a kind of diagnostic tool.
DLP
Digital Light Processing (DLP) is a type of video projector technology that uses digital micromirror devices. Some DLP have a TV tuner, which makes it a kind of TV screen. It was originally developed in 1987 by Dr. Larry Hornbeck from Texas Instruments. While the DLP imaging device was created by Texas Instruments, the first DLP-based projector was introduced by Digital Projection Ltd. in 1997. Digital Projection and Texas Instruments were both awarded the Emmy Awards in 1998 for the invention of DLP projector technology. DLP is used in a variety of display applications from traditional static displays to interactive displays as well as non-traditional embedded applications including medical, security, and industrial use. DLP technology is used in DLP front projectors (standalone projection units for classrooms and businesses primarily), but also in private homes; in this case, the image is projected onto the projection screen. DLP is also used in DLP rear projection television sets and digital markings. It is also used in about 85% of digital cinema projections.
Plasma
The plasma display panel (PDP) is a common type of flat panel display for large 30 inch (76 cm) or larger TV screens. They are called "plasma" displays because the technology uses tiny cells containing electrically charged ionized gases, or what is essentially a better known space as a fluorescent lamp.
LCD
Liquid-crystal-display television (LCD TV) is a television set that uses LCD screen technology to produce images. LCD televisions are much thinner and brighter than cathode ray tubes (CRTs) of the same screen size, and are available in much larger sizes (eg, 90-inch diagonals). When production costs go down, this combination of features makes the LCD practical for a television receiver. LCDs come in two types: those that use cold cathode fluorescent lamps, called LCDs and which use LEDs as backlights are referred to as LEDs.
In 2007, LCD televisions topped CRT-based television sales worldwide for the first time, and their sales figures were relative to other accelerated technologies. LCD TVs are quickly replacing the only major competitors in the big screen market, plasma display panels and rear projection televisions. In the mid-2010s LEDs especially LEDs became, by far, the most widely produced and sold television screen types. LCD also has flaws. Other technologies overcome these weaknesses, including OLED, FED and SED, but by 2014 no one has entered production widely.
OLED
An OLED (organic light-emitting diode) is a light-emitting diode (LED) in which the emitting electroluminescent layer is a film of organic compounds that emit light in response to an electric current. This organic semiconductor layer is located between two electrodes. Generally, at least one of these electrodes is transparent. OLED is used to create digital displays on devices such as television screens. It is also used for computer monitors, portable systems such as mobile phones, handheld game consoles and PDAs.
There are two main families of OLEDs: they are based on small molecules and those that use polymers. Adding a cell ion to OLED creates a light-emitting electrochemical cell or LEC, which has slightly different operating modes. OLED view can use passive-matrix (PMOLED) or active-matrix (AMOLED) schemas. Active-matrix OLEDs require thin film transistor backplanes to enable or disable individual individual pixels, but allow for higher resolution and larger screen sizes.
OLED screen works without backlighting. Thus, it can display solid black levels and can be thinner and lighter than the liquid crystal display (LCD). In low ambient light conditions such as darkroom OLED screens can achieve higher contrast ratios than LCDs, whether LCDs use cold cathode fluorescent lamps or LED backlights. OLED is expected to replace other forms of display in the near future.
Screen resolution
LD
Low definition television or LDTV refers to television systems that have lower screen resolutions than standard definition television systems such as 240p (320 * 240). It is used in handheld televisions. The most common source of LDTV programming is the Internet, where the mass distribution of high resolution video files can overwhelm the server computer and take too long to download. Many mobile phones and portable devices such as Apple's iPod Nano, or Sony's PlayStation Portable use LDTV video, because higher resolution files will be overkill for their small screen needs (320 × 240 and 480ÃÆ'â € "272 pixels respectively). The current generation of iPod Nanos has an LDTV display, as do the first three generations of iPod Touch and iPhone (480ÃÆ'â € "320). For the first few years of its existence, YouTube only offers one low-definition resolution of 320x240p at 30fps or less. VHS consumer-level video recording can be considered as SDTV because of its resolution (about 360 ÃÆ'â € "480i/576i).
SD
Standard definition television or SDTV refers to two different resolutions: 576i, with 576 lines of interconnected resolution, derived from European developed PAL and SECAM systems; and 480i based on the NTSC Committee of the National Television System of America. SDTV is a television system that uses a resolution that is not considered a high definition television (720p, 1080i, 1080p, 1440p, 4K UHDTV and 8K UHD) or high definition television (EDTV 480p). In North America, digital SDTV is broadcast in a 4: 3 aspect ratio similar to the NTSC signal with the widescreen content being cut. However, in other parts of the world using PAL or SECAM color systems, standard definition television is now typically displayed with a 16: 9 aspect ratio, with transitions occurring between the mid-1990s and mid-2000s. Older programs with a 4: 3 aspect ratio are shown in the US as 4: 3 with non-ATSC countries that prefer to reduce the horizontal resolution by anamorphically scaling the parsed images.
HD
High definition television (HDTV) provides a much higher resolution than standard definition television.
HDTV can be transmitted in various formats:
- 1080p: 1920ÃÆ' â € "1080p: 2,073,600 pixels (~ 2.07 megapixels) per frame
- 1080i: 1920ÃÆ' â € "1080i: 1,036,800 pixels (~ 1.04 MP) per field or 2,073,600 pixels (~ 2.07 MP) per frame
- Non-standard CEA resolutions exist in some countries such as 1440ÃÆ'â € "1080i: 777,600 pixels (~ 0.78 MP) per field or 1,555,200 pixels (~ 1.56 MP) per frame
- 720p: 1280ÃÆ' â € "720p: 921,600 pixels (~ 0.92 MP) per frame
UHD
The ultra-high-definition television (also known as Super Hi-Vision, Ultra HD television, UltraHD, UHDTV, or UHD) includes 4K UHD (2160p) and 8K UHD (4320p), which are the two digital video formats proposed by NHK Science & amp. ; Technology Research Laboratory and established and approved by the International Telecommunication Union (ITU). The Consumer Electronics Association announced on October 17, 2012 that "Ultra High Definition" or "Ultra HD" will be used for displays that have at least 16: 9 aspect ratios and at least one digital input capable of bringing and delivering original video with a minimum resolution of 3840ÃÆ' â € "2160 pixels.
North American consumers buy new televisions on average every seven years, and the average household has 2.8 televisions. In 2011, 48 million are sold annually at an average price of $ 460 and size 38 in (97 cm).
Content
Programming
Getting TV programs publicly displayed can take many different ways. After production, the next step is to market and ship products to any open market to use them. This usually happens on two levels: Original run or First run: the producer creates a program of one or more episodes and displays them on stations or networks that have paid for the production itself or whose permission has been granted by the television producer to do the same.
Source of the article : Wikipedia
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