Presentation on the topic of television development. Presentation on the topic "television". The beginning of television in the USSR

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: “If the TV and the refrigerator were not in different rooms, then some of us would have died from lack of physical activity. »Stephen Patrick Morrissey

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The invention of radio and cinema
Alexander Stepanovich Popov May 7, 1895 - radiotelegraph 1919 - transmission of the first sounding word

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Cinematograph - Auguste and Louis Lumiere
1895 - the first movie camera

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Nipkow disk 1884 (1923) first mechanical image scanning device
A rotating opaque disc, up to 50 cm in diameter, with holes inscribed in an Archimedes spiral - ("electric telescope"). The image was scanned with a light beam based on one (!) Photocell with the subsequent transmission of the signal to a special converter. The number of holes was from 30 to 200. There was a neon lamp behind the disk.

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Mechanical TV
The screen glowed with a pink light, until the 40s. - green The picture was blurred, in the form of shadows and contours, "mute" 1930. A television laboratory was created at the All-Union Electrotechnical Institute, two radio receivers were required to receive a television broadcast

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Start of production of mechanical televisions
April 15, 1932 Pravda newspaper: "The Leningrad plant" Comintern "began to develop the first 20 Soviet TV sets" B-2 "with a screen size of 3x4 cm" The TV was connected to a radio receiver instead of a loudspeaker.

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First television broadcast
April 30, 1931 Pravda newspaper: “Tomorrow for the first time in the USSR there will be an experimental broadcast of television (far-sightedness) by radio. From the short-wave transmitter RVEI-1 of the All-Union Electrotechnical Institute at a wavelength of 56.6 meters, an image of a live face and photographs will be transmitted. ”More than 30 homemade TVs were operating in the capital
The construction of the Moscow Television Center had not yet been completed, and there was no roof over the pavilion, when the trial broadcasts of films began. The first took place on March 25, 1938 - the film "The Great Citizen" was shown. On September 5 of the same year, test studio broadcasts began. The Act on the completion of the construction of the Moscow Television Center was signed on December 31, 1938, and regular broadcasting began on March 10, 1939. The receiving network consisted of 100 televisions installed within a radius of up to 30 km from the transmitter.

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Cathode ray tube 1907
Boris Lvovich Rosing Lecturer at the St. Petersburg Institute of Technology The cathode tube was invented by the Englishman W. Crookes, improved by the German scientist K. Brown 1911 - "privilege No. 18076" for the world's first electronic television set 1912 - gold medal and prize named after an honorary member of the Russian technical society K.F.Siemens 1922 - state patent for "radio telescope"

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The first electronic TV
1925 year. Swedish engineer John Byrd. The first transmission of recognizable human faces and the first television system capable of transmitting moving images. Late 1936. RCA American Research Laboratory. Vladimir Kozmich Zvorykin The first electronic TV set suitable for practical use (iconoscope) 1939 the first TV set designed specifically for mass production. The RCS TT-5 is a massive wooden box with a 5-inch screen.

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Soviet electronic TV
November 15, 1934 - the first broadcast with sound 1949 KVN 49 (Kenigson - Varshavsky - Nikolaevsky)

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Development of television
1950 - 1st long wire remote control. 1954 RCA. The first color TV. Screen diagonal 15, 19, 21 inches. Price - $ 1000 1960 - The first semiconductor TV. Firm SONI. 1967 - production of color TV sets in the USSR.

The beginning of the development of phototelegraphy is associated with the projects of A. Baine (1842), F. Bakewell (1847) and J. Caselli (1862). The difference between phototelegraphy and television is about the same as between photography and cinema. Early successes in transmitting still images over communication lines drew the attention of scientists and inventors to the problem of television. But for the transition from phototelegraphy to television, that is, to the direct transmission of moving images, new methods and technical means were required, and enormous technical difficulties had to be overcome.

Next stage: Kern system An attempt to build a television system by analogy with the structure of the human visual apparatus. The centers of the cerebral cortex, where visual perceptions are created, were represented by light sources (for example, incandescent bulbs) located on a second panel at the receiving site. The conversion of the optical image into electrical signals in the Kern system had to be carried out simultaneously and continuously by all photoresistors. All changes in the transmitted image would be reflected in the change in the brightness of the glow of the light sources in the receiving device, which would, in principle, allow the transmission of moving images.

The system of M. Sanlek, A. di Paiva and PI Bakhmetyev The transition from a multichannel image transmission system to a single-channel system was carried out. Unlike the purely electrical static Kern system, which did not contain any mechanical moving parts, the Sanlek, de Paiva and Bakhmetyev systems required the use of more or less complex mechanisms for scanning or decomposing an image into elements.

It was an opaque circle of large diameter, at the outer edge of which small round holes are located in a spiral at the same angular distance from one another. Each subsequent hole is displaced by its diameter to the center of the disc. In the transmitter, the disk was located between the transmitted object and the selenium photoresistor. The image of the transmitted object was focused by the lens onto the plane of the disk. When the disk rotated through its holes, light passed to the photoresist alternately from individual image elements. Each hole produced one line of the image. For one revolution of the disk, the photoresistance was successively affected by light from all the image elements, which corresponded to the transmission of one frame.

BL ROSING - Creator of Television Achievements and Dates: Used an electron beam to reproduce images in an electric telescope system. In 1902, BL Rosing used a cathode-ray tube in the receiver of a system with electrochemical elements on the transmitting side. On July 25, 1907, he applied for the granting of a privilege to him for the invention of the Method for the electrical transmission of images. He received a gold medal and an award named after an honorary member of the society K.F.Siemens.

In 1924 BL Rosing recreated his system and made a number of improvements to the transmitting and receiving devices. A new optical system has been developed to obtain images that are undistorted in terms of brightness, clarity and magnification. The experiments carried out by S. L. Rosing at LEEL in 2000, showed the complete efficiency of his television system and the correctness of the principles on which it was based. Under laboratory conditions, simple images could be transmitted with a sharpness of 48 lines. Rosing acts as a committed supporter and promoter of electronic television

A real breakthrough in electronic television technology was made by B. Rosing's student V. K. Zvorykin. in 1923 he applied for a television based entirely on the electronic principle, and in 1931 he created the world's first transmitting electron tube with a mosaic photocathode, called the "iconoscope", which laid the foundation for the development of electronic television. The iconoscope was the first electronic transmitting television tube, which allowed the mass production of television receivers to begin. Then Zvorykin began to create a fully electronic television system. A great contribution to the development of television was made by Soviet scientists and inventors - S. I. Kataev, P. V. Shmakov, P. V. Timofeev, G. V. Braude, L. A. Kubetsky, A. A. Chernyshev and others. In the second half of the 1940s, the decomposition of the image transmitted by the Moscow and Leningrad centers was increased to 625 lines, which significantly increased the quality of television broadcasts.

If in 1953 only three television centers were operating, then in 1960 there were already 100 powerful television stations and 170 low-power relay stations, and by the end of 1970 - up to 300 powerful and near low-power television stations. On the eve of the 50th anniversary of the Great October Socialist Revolution, on November 4, 1967, the All-Union Radio and Television Transmitting Station of the Ministry of Communications of the USSR was put into operation, which was named after the 50th Anniversary of October by the Decree of the Council of Ministers of the USSR All-Union Television Center in Ostankino

Further development of television In 1954, the Moscow Television Center on Shabolovka carried out the first experimental broadcasts with alternate transmission of color components. In 1956, in the laboratory of the Leningrad Electrotechnical Institute of Communications named after I. M. A. Bonch-Bruevich designed and manufactured, under the leadership of P. V. Shmakov, a color television installation with simultaneous transmission of colors. In January 1960, the first color television broadcast took place in Leningrad from the experimental station of the Leningrad Electrotechnical Institute of Communications. In March 1965, an agreement was signed between the USSR and France on cooperation in the field of color television on the basis of the SECAM system. On June 26, 1966, it was decided to select the joint Soviet - French SECAM color television system for implementation in the Soviet Union. The first broadcasts on jointly Soviet - the French system began in Moscow on October 1, 1967, at the same time the release of the first batch of color televisions was timed.On the day of the 50th anniversary of the Great October Socialist Revolution (November 7, 1967), the first color television broadcast from Red Square of the parade and demonstration took place workers.

And the first remote control was created in 1950. This remote control was connected to the TV through a long wire. A few years later, Robert Adler proposed the use of ultrasound for this purpose. Attempts have also been made to use a beam of visible light. But in the end we settled on infrared radiation, which is still used today.

In televisions, an image is formed from frames that change at a certain frequency, and each frame consists of a certain number of lines. It is known that the eye begins to distinguish flickering (frame changes), starting at a frequency of 41 Hz (with a white source brightness of 30 cd / m2). Therefore, the frame rate must be higher. In television broadcasting, each frame is transmitted in two fields, one of which contains all the odd lines, and the other contains all the even lines. In the world, there are basically two television scan standards: European at 625 lines at 25 frames per second and American at 525 lines at 30 frames per second. This uses interlaced decomposition with two fields per frame. These standards are technically and economically viable, but they are only sufficient for close-up images. When transferring images containing fine details, the clarity of the images drops dramatically. In addition, in an interlaced screen with two fields, interlaced flickering appears in the frame, due to different brightness of the lines of successively reproduced fields. Viewing the TV is very tiring for the nervous system, because low image quality and various flashes are perceived by the subconscious. T.N. The “green” standard for safe television broadcasting requires scanning at a frame rate of at least 90 frames per second. Another reason for the effect on the nervous system is the noise of the TV line generator. This frequency is about 16 kHz (at the limit of human hearing), however, with prolonged exposure it causes fatigue.

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A bit of history

In December 1936, the RCA laboratory demonstrated the first practical television set. In April 1939 RCA introduced the first television to the general public. All models were housed in handcrafted walnut cabinets.

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• By the early 1950s, a feasible color television system had been invented. But it took many years before color television became the norm.
• The gradual miniaturization of technology made it possible to shrink the cases and make them less intrusive, and the size of the screens increased.