power line communication

.e., facsimile of printed matter or pictures) use a similar mechanism. In the case of intercontinental telecommunication, two or more satellites are linked together. High frequency radio and submarine cable systems have been widely used for long- distance overseas telecommunications. The high frequ..

Propagation of EM Waves in Atmosphere - In an Earth environment, electromagnetic waves propagate in ways that depend not only on their own properties but also on those of the environment itself. Since the various methods of propagation depend largely on frequency therefore the complete electromagne..

Wave propagation in unbounded medi..

. So, the signal power progressively decreases with increasing distance. The receiver operates on the output signal from the channel in preparation for delivery to the transducer at the destination. Receiver operations include amplification to compensate for transmission loss. These also ..

>(iii) Immunity to electromagnetic interference, which is an inherent characteristic of an optical fiber viewed as a dielectric wave guide. (iv) Small size and weight, characterized by a diameter, which is no greater than that of a human hair. (v) Ruggedness and flexibility, exemplified by very hig..

Let us now discuss the basic principles of wireless radio communications. We shall mainly concentrate on the principle of amplitude modulation and demodulation. The simplest scheme of wireless communication would be to convert the speech or music to be transmitted to electric si..

>Full names of the units do not begin with capital letter E.g., newton and not Newton. The symbols of units, named after a scientists, have initial capital letter. E.g., J for joule, K for Kelvin. Symbols do not have plural form. E.g., 5 kg (not 5 kgs), 25 m (not 25 metres). A unit symbol is repres..

The transmission lines used in telephony are of two kinds: open- wire and cable. The open-wire lines are gradually being superseded by cable construction, either overhead or underground, for two principal reasons. In the first place, many more circuits can be accommodated-there ..

. A signal traveling from west to east encounters the first hybrid coil, where part of the power enters the west-east amplifier by way of the centre taps on the main winding..

The development of the laser has opened many avenues of investigation and improved many others. The important characteristics that have contributed to its usefulness in these many areas are tile coherence, monochromaticity and great intensity of its radiation. (i) The smallest lasers used for telep..