TELEVISION STORY

1817 Jons Jacob Berzelius (Swedish, 1779-1848) discovers the property of selenium to increase or decrease its resistivity according to received illumination. This property will give rise to the photovoltaic, average cell to transform the light while electrical current. 1843 tests of London-Portsmouth transmission by automatic telegraph Alexander Bath (English, 1810-77), abandoned for lack of synchronization between transmitter and receiver. 1848 synchronization successful by Bakewell (Amér.) by rolling up arrival and starting sheet by cylinders turning at constant speed. 1856 France, Giovanni Caselli (Florentin abbot, 1815-91) carries out a similar system (pantélégraphe) which will be used for the transmission of drawings and letters (on the lines of the electric telegraph) in 1866 between Paris and Lyon, then prolonged between Lyon and Marseilles. 1873 2 English telegraphists, Joseph May and Wiloughby Smith, confirm work of Berzelius on selenium. 1875 G.R. Carey (Amér.) propose to use selenium for the transmission of the remote images. 1878 idea taken up by Constantin Senlecq [ france, 1842-1934; notary with Ardres (Pas-de-Calais) ], which makes appear, in the Electric light, an article on the "télectroscope" (in 1877, it had succeeded in transmitting an image with an autographic telegraph). Principles of the 1st television apparatuses mechanical: the image is projected on a multitude of small grains sensitized with selenium, then analyzed point by point by a revolving switch. The apparatus is connected to a receiver made up of tiny lamps, each one connected to one of the selenium grains. With the reception of the signal, the lamp shines more especially as the grain corresponding was more violently enlightened. This apparatus will be never carried out; it would have been too cumbersome and would have prohibited the transmission of the image at long distance. 1880 Maurice Leblanc (france, 1857-1923) proposes to project on the image a mobile luminous ray, 1st step towards the technique of the flying spot (developed), used then in the apparatuses of telecinema (transformation of the image film into image television). 1884-6-1 patent of Paul Nipkow (German, 1860-1940) for an analyzer disc of images which will be used until 1939, for television. 1887 Heinrich Hertz (German, 1857-94) shows that the ultraviolet rays of the light cause an emission of negative electric charges by certain metals: discovered electrons (explained by Albert Einstein in 1905). 1889 Lazare Weiller (france, 1858-1928) replaces the disc of Nipkow by a wheel including/understanding a succession of mirrors of different slope. 1897-15-2 publication of work of Karl Ferdinand Braun (German, 1850-1918) on the rays and the cathodic oscillograph announcing the electronic analysis of the image. 1898 Marcel Brillouin (france, 1854-1948) replaces the holes of the disc of Nipkow by small embedded lenses and thus increases the quantity of light received by the cell.

1900 1st appearance of the word television (World Fair of Paris). 1907 1st photograph transmitted by Arthur Korn (German, 1870-1945), between Verdun and Paris. Process improved by Édouard Belin (france, 1876-1963) since 1911. 1907-11 Boris Rosing (Russian, · 1918) designs the cathode ray tube which envisages an electronic sweeping of the image to be transmitted. 1921 1st facsimiled message sent by Belin de France to the USA: phototelegraphic apparatus: the image or the text is rolled up on a cylinder and is lit. The light, variable beams according to the colour of paper at the successively explored places, are considered on an electric eye connected by a telegraph network to a receiver. On a photosensitive paper, the reconstituted light beam is projected. 1923 1st system of TV of John Logie Baird (English, 1888-1946): televisor (launched 1929) using a disc of Nipkow to the emission and a valve amplifier with the reception and, to modulate the light, an electromagnetic obturator. Definition of the 1st image transmitted by 18 lines. -29-12 patent of the viewfinder: 1st electron tube analyzer of images, of Wladimir Kosma Zworykin (Russian, 1889-1982), raises of Rosing, emigrant in the USA, realized for Westinghouse (public demonstration 18-11-1929, left 20-12-1938); allows the high definitions and constitutes the true departure of the TV. 1924 Charles Jenkins (Amér., 1867-1934) creates a neon light with cathode punt which makes it possible to better follow the variations of the current-light. Rene Barthélemy (france, 1899-1954) invents a disc with images. 1925 Baird integrates the lamp of Jenkins into its apparatus; 1st public demonstration in April in the store Selfridge' S (London). 1926-27-1 official birth of the TV. Baird, to Royal the Institution, submits, from one part to another, the image of a human figure. It melts the 1st co. of television, Baird Television Company. 1927 Bell Telephone organizes a broadcast television on line between New York and Washington. -9-2 Baird transmits the 1st image over the Atlantic (wavelength 35 m): its face (in 30 lines) of Coudlson (Surrey) with Hartsdale (New York). 1928-July 1st tests of TV color (GB.) by Baird. 1929-30-9 Baird: definition of 30 lines for experimental emissions of the BBC (transmitting of Daventry of 11 H at 11 a.m. 30, waves moy. of 363 m; power 1,5 kw). 1st tests of TV to 50 lines between New York and Washington (380 km) by Bell. -8-3: 1st regular emissions of 30 lines in Germany (by Deutsche Reichspost). 1st French apparatus with neon light and disc of Nipkow: Barthélemy and his/her collaborators Strelkoff and Marius Lamblot.

1930-July retransmission of a part of Pirandello. 1931 Henri de France (French, 1911-86) melts in Le Havre the general Co of television and develops apparatuses with 60 lines. Marc Chauvierre, at Integra, produces a camera in flying spot used later in Radio Lyon, and puts on the market of the general public material. -3-6: 1st report full air (GB, Baird). 1932 1st experimental emission of electronic TV in New York. 1936 station of TV of Alexandra-De luxe hotel in London (BDC); 2 standards, Baird (240 lines), Marconi (405 lines). Until the 2-11, 1st regular emissions of electronic TV. Germany, during 16 J, 150 000 spectators attend on line the OJ of Berlin, retransmitted by cable in Hamburg, Leipzig, Munich, Nuremberg. Chauvierre presents at the Sorbonne the 1st French receiver with general public cathode ray tube, the visiodyne.

1940 international fair of New York. -30-4 regular public emissions. 1941 regular emissions in the USA starting from the Empire State Building. 1943 1st television news with Schenectady (the USA). 1944 1st system of TV color by John L Baird. 1945 Marc Chauvierre and Jacques Donnay present at the GTIR a system with transmission of the image and the sound on the very carrying one (its numerically).

1951-26-6: 1st public emission of TV color (CBS in New York). 1952 kinéscope, developped at the point by O B Hanson, vice-Pt of NBC. 1954-6-6 Eurovision inaugurated (festival of the flowers of Montreux; pope speaking about the Vatican). 1962-11-7: 1st regular connection America-Europe via the satellite TELSTAR d' Andover (Maine, the USA), collected in Pleumeur-Bodou. 1968-févr. retransmission of the OJ of Grenoble, on line in 32 countries; more than 600 million televiewers. 1969-21-7 Neil Armstrong (on line) 1st man to be gone on the Moon. 1991-18-12 Time Warner opens in Queens (New York) an experimental cabled system with 150 channels (extension to 500 envisaged). 1994 1st transmissions numerical TV general public by DirecTV in the USA.

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