Television* means ‘to see from a distance’. The desire in…

““Television* means ‘to see from a distance’. The desire in man to do so has been there for ages. In the early years of the twentieth century many scientists experimented with the idea of using selenium photosensitive cells for converting light from pictures into electrical signals and transmitting them through wires. The first demonstration of actual television was given by J.L. Baird in UK and C.F. Jenkins in USA around 1927 by using the technique of mechanical scanning employing rotating discs.However, the real breakthrough occurred with the invention of the cathode ray tube and the success of V.K. Zworykin of the USA in perfecting the first camera tube (the iconoscope) based on the storage principle. By 1930 electromagnetic scanning of both camera and picture tubes and other ancillary circuits such as for beam deflection, video amplification, etc. were developed. Though television broadcast started in 1935, world political developments and the second world war slowed down the progress of television. With the end of the war, television rapidly grew into a popular medium for dispersion of news and mass entertainment. Television Systems At the outset, in the absence of any international standards, three monochrome (i.e. black and white) systems grew independently. These are the 525 line American, the 625 line European and the 819 line French systems. This naturally prevents direct exchange of programme between countries using different television standards.Later, efforts by the all world committee on radio and television (CCIR) for changing to a common 625 line system by all concerned proved ineffective and thus all the three systems have apparently come to stay. The inability to change over to a common system is mainly due to the high cost of replacing both the transmitting equipment and the millions of receivers already in use. However the UK, where initially a 415 line monochrome system was in use, has changed to the 625 line system with some modification in the channel bandwidth. In India, where television transmission started in 1959, the 625-B monochrome system has been adopted.””

— Anonymous