History of development of radio-television Еxecuted: Abdilov Alymbek
At radio sources The first steps in again arising areas of equipment inevitably happen are connected with the previous scientific and technical achievements. Always it is possible to find a certain physical basis in each new technical area. As such physical basis for possibility of emergence of radio engineering the electromagnetic field served. The doctrine about this field was developed by many outstanding scientists.
Michael Faradej (1791 -1867). In 1837 г. English physicist Faradej in the "Pilot studies on an electricity" put the beginnings of our ideas of influence of electric currents. They brought "being direct proximity from them a matter into some special condition which was before indifferent"
Henry Rudolf Gerts (1857 -1894) In 1887 г. German physicist Henry Gerts confirmed with classical experiences Maxwell's theoretical conclusions. For detection of electromagnetic waves of physics used the device called by the vibrator of Hertz. This device represents an open oscillatory contour. To an open contour it is possible to pass from closed if gradually to move apart condenser plates, reducing their area and at the same time reducing number of rounds in the coil. In the end result the direct line will turn out. It also is an open oscillatory contour. For initiation of fluctuations in such contour the wire needs to be cut in the middle so that there was the small air interval called spark. In that place where a cut, on the wire ends brass balls spread. Both parts of the conductor charged to a high potential difference. When the potential difference exceeded some limiting value, the spark slipped, the chain became isolated, and in an open contour there were fluctuations. Thus, it has been established that electromagnetic waves extended rectilinearly and speed of these waves is equal to a velocity of light (300000 km/c). The basic principles underlying transfer to electromagnetic energy at distance have been open and experimentally proved.
Edward Judzhin Disair Branli (1844 -1940) "If to make a contour consisting of an element of Daniel, a sensitive galvanometer, the metal conductor and an ebonitovyj plate with the put copper or tubes with sawdust, mostly passes, only insignificant current. However resistance sharply decreases - that is visible on a strong deviation of a galvanometer - if near a contour to make one or several electric charges". This phenomenon has been described by Branli in 1890
Oliver Joseph Lodge (1851 -1940) "This device which I name когерером, is surprisingly sensitive as the detector герцевских waves" - a fragment from Lodge's report "Creation of Hertz", read in the British royal society on June, 1 st 1894 г. Когерер represented a glass tube with two opposite placed electrodes between which there was metal sawdust. At influence on such device of a high-frequency electromagnetic field its conductivity sharply increased, but at field elimination the described device in the initial condition didn't come back. To return a tube with sawdust in an initial condition, it was necessary for stirring up. For this purpose Lodge used different ways, but all these influences were casual, in any way not coordinated with arrived on когерер signals from the transmitter. For this reason receiver Olivera wasn't suitable for a radio communication
Alexander Stepanovich Popov's biography Alexander Stepanovich Popov was born on March 16 (on March 4) 1859 in the Urals in the settlement Turinsky Mines of the Perm province (now the city of Krasnoturyinsk, Sverdlovsk region), a family of the priest of local church. The production situation promoted emergence in the boy since early years of interest to equipment. В 1877 г. A. S. Popov after the termination of general educational classes of the Perm theological seminary arrived on mathematical office of physical and mathematical faculty of the Petersburg university. From obligatory occupations he devoted all free time to laboratory researches on physics. In student's years A. S. Popov was involved by problems of the latest physics and electrical equipment. At the successful termination of university in 1882 г. it presented the dissertation on a subject: " About principles magnitno - and dinamoelektrichesky cars of a direct current". From 1883 to 1890 A. S. Popov was the teacher on chair of physics of the Mine officer class and with 1890 on 1901 in Technical school of sea department in Kronstadt. In 1887 of Priests took an active part in supervision of a solar eclipse and was one of members of Krasnoyarsk expedition. In 1901 г. Priests became the professor of the Petersburg electrotechnical institute, and in 1905 г. it chose as the director of this institute.
A. S. Popov's first radio receiver On May 7 1895 г. at meeting of Russian physical and mathematical society A. S. Popov showed the device designed by it for reception and registration of electromagnetic fluctuations. As the device reacting to an electromagnetic field, the scientist chose a coherer. But before using it in the receiver scheme, A. S. Popov carried out a number of research works for coherer improvement. As a result it came to a design of "tube" with platinum plates and with an iron powder, having achieved satisfactory constancy of sensitivity. Further A. S. Popov achieved such combination that communication between the sawdust, caused by electric fluctuation, collapsed immediately automatically. For this purpose it used a hammer of an electric call which stirred up a tube. To increase sensitivity of the device, A. S. Popov one of coherer conclusions earthed, and another attached to highly lifted piece of a wire, having created the first reception aerial for wireless communication. Grounding turns carrying out surface of the earth into a part of an open oscillatory contour that increases range of reception. Still the device turned on the electromagnetic relay and the power supply. As the transmitter for this device the spark rated sportsman raising electromagnetic fluctuations in the aerial served
Television Introduction The area of electric communication tests now the revolutionary changes connected with globalization of production and economic processes in the world community; to it there corresponds origin and development of new technologies: merge of computer and telecommunication systems, introduction of fiber-optical equipment, development of digital methods and transfer devices, storage and information processing. Now branches of telecommunications develop prompt rates. With equipment modernization quality of traditional services of electric communication improves, there are new. Among them the major role for the decision information, cultural, propaganda and even military tasks is played by a television broadcasting. In this work it will be a question of history of emergence and television development, about its main types and characteristics, about current trends in the field of a television broadcasting and about its future.
Mechanical television The principle of optiko-mechanical development of a beam was so simple that on October 2, 1925. Englishman John Lodzhi Byrd received the image on the receiver screen, and on January 26, 1926. Publicly showed "the moving picture" to members of Royal institute of Great Britain. Certainly, it was no modern "the television picture", on it there were only silhouettes, but the beginning was necessary. A year in J later. Byrd increases quantity of openings on a disk to 30. It is necessary to note that the essential increase in resolution of the screen was insuperable because of design features of a disk of Nipkov: the more openings on it settled down, there was their size and, respectively, less light got on a selenic photo cell less. Sooner or later there should come a limit when the quantity of light would become insufficient for its transformation to an electric signal. The disk settled down in the TV camera which sizes were impressive, the screen of the accepting television receiver was 3 x 4 see. To enlarge the screen till the size of the average photo (9 x 12 cm), the disk in a television camera should be more than two meters in diameter.
Color television Strangely enough, works in the field of color television have begun in parallel with black-and-white "дальновидением". The first color three-componental system of TV ("Telephotos") was offered in 1900 by Alexander Apollonovich Polumordvinov (1874 -1942). Beam development was made by means of a disk of Nipkova with color optical filters. In 1902 of Semimordvinians makes an application on the new device - "the device for transfer of the image and a way of this transfer in connection with a simultaneous sound transmission". Unfortunately, the equipment hasn't been finished, though, according to experts, the project based on methods of a consecutive color mixture, was quite efficient. In 1907 г. The patent for the project of two-colored television with simultaneous color transfer to Germany the native of Russia has developed Ovanes Abgarovich Adamjan (1879 -1932). Later he moves to Russia and in 1925 Patents three-componental consecutive transfer of colors (RGB). In the developing device was three series of apertures, each of which was closed red, dark blue and green by optical filters. To realize this idea in 1928 It was fated to the well-known J. Берду. The basic problem of the given scheme consisted in its incompatibility with black-and-white TV-receivers, besides, the epoch of mechanical television came nearer to the end.
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