текст 4 резюме

1. The author isn’t mentioned. Transmission Media. English for communications students. Kozhevnikova T. V., 2010 (twenty ten), pp 202-205(two hundred two to two hundred five)

2. Transmission Media.

3. The aim of the article is to describe the advantages and disadvantages of different types of transmission media.

4. The research method used in the article description, comparison and analysis.

5. Today there are 4 methods of data transmission.

Cорper wire cable did not have a shield and therefore the signal was able to leak out. However, for voice communications it was quite satisfactory.

Соaxial cable consists of a single strand of copper running down the aхis of the cable. This strand is separated from the outer shielding by an insulator made of dielectrics. А conductive shield covers the cable. Because of the construction of the cable very high frequencies can be carried without leaking out.

Fiber is the third transmission medium. Transmission over fiber utilizes frequencies a million times higher, when transmission over copper utiluzes. This is another way of saying, that the predominant difference between electromagnetic waves and light waves. This difference permits transmission speeds of immense magnitudes. Fiber comes in several forms; the two predominant ones are multimode and single-modе.

Wireless communications is the final option as a transmission medium. This can take several forms: microwave, synchronous satellites, cellular, personal communications service, etc.

6. The article describes several periods in the development of information transsmition methods using telecommunications.

7. The author comes to the conclusion that each transmission medium has its own advantages and disadvantages, but at the present time wireless communication is the most relevant because it provides communication mobility.