2_sem_английский / Doc18

TEXT 11A

RADIO AND TELEVISION

The radio is probably the only invention, which has found universal recognition and appli­cation in a comparatively short time.

Radio supplies the communication service, which is so essential to the modern world, and meeting these needs it has become a rapidly developing industry itself. It is from radio that the subject of electronics was born which being applied to automation brought such remarkable changes to the technique of today.

The fastest, most reliable way to detect an artificial satellite and to determine its orbit is by radio. It is by means of radio that we receive most of the information collected by the satellites at the borders of space. Without radio we should be hardly able to observe them at all. Indeed, radio makes it possible to follow them even when they are too small to be visible.

More obvious still is the ever-growing influence on mankind of radio broadcasting, both sound and television. Along with the construction of television centers powerful relay-stations located at considerable distances from the main television centers are being built. Extensive work is also being carried on in the field of colour television.

Having already made remarkable progress, radio and television continue to develop and to find wider and wider application in science, industry and agriculture. They enable us to measure distances on land and water, to see through the surface. Specially designed radio and television sets can be found on board a ship, on board a plane, on the very bottom of the sea.

Radio and television are not only the reliable means of communication but also effective means of educating people, spreading knowledge and ideas and raising the cultural level of the population.

In radio astronomy radio telescopes are used to investigate the Universe, to obtain data on chemical composition and surface conditions of the Sun and other planets.

Radio engineering technique is widely used in radio telemetry to indicate or record a mea­surable quantity at a distance.

At present we produce equipment for powerful broadcasting and television centers and ra­dio-relay stations, electronic computers, radar stations, telecontrol and telemetric systems, etc.

Radio broadcasting is the technique of use of radio (electromagnetic) waves for wireless transmitting of sound.

Radio waves are produced at the broadcasting station and radiated by the aerial. Radio waves generated by the radio transmitter and emitted by the aerial propagate in all directions. Radio- receivers receive, transform and amplify the energy of radio waves into audio signals so that they can reach the loudspeaker, headphones, a relay, recording equipment, etc. Radio receiver is one of the main elements of broadcasting, communication systems, television, radar and many other fields of engineering. The lower the power of signals received, the higher sensitivity of the receiver should be.

Broadcasting based on digital coding has revealed many advantages over conventional broad­casting. It consists in converting sound waves into series of digits .and their subsequent trans­mission in the form of monofrequential pulses. A signal is then received and after amplification is sent to the acoustic system for reproduction. Digital coding enhances the quality of broad- casting, makes it possible to reduce considerably the size of new receiver - decoders. In digital broadcasting more than one station can use one and the same wavelength without interference.

These few examples give but a poor idea of what other uses radio and television might still find in various spheres of life and how much they would contribute to the further progress of science.