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GATEWAY EXCHANGE

The gateway exchange is the center at which the international exchange multiplex equipment and ancillary equipment, for international telephone and/or telegraph, Telex data, Television and Facsimile are located.

NWD - NATION WIDE DIALING SYSTEM

The Nation Wide Dialing System ( NWD ) was introduced in Pakistan between a few cities in 1976. This system has now extended to all over the country.

TELEPHONE TRAFFIC AND TRUNKING PRINCIPLE

Telephone traffic means, number of subscribers .trying to contact other subscribers. It has an interesting similarity with vehicular traffic on a road in a city.

Radio Frequency - RF Spectrum

Radio signals are transmitted through electromagnetic waves, also called radio waves, in radio communication system. The radio waves have a wide frequency range starting from a few ten kilo Hertz (kHz) to several thousand Mega Hertz (MHz).

Distributed Line Constant

Distributed OR Primary Line Constant and Equivalent Circuit When we AC input is applied to the transmission line its inductive reactance (XL) increases with increase in frequency. As the transmission line is made of the millions of small particles, therefore the chain of those particles make the transmission line to

NOISE

With reference to an electrical system, noise may be defined as any unwanted form of energy which tends to... Read more about NOISE

TERMS OF MODULATION

The ratio of the frequency deviation to the modulating frequency is known as the modulation index. Read more about TERMS OF MODULATION

Pre-emphasis and De-emphasis

Pre-emphasis circuit Pre-emphasis refers to booting the relative amplitudes of the modulating voltage for higher audio frequencies from 2 to approximately 15 KHz.

TV - TELEVISION TRANSMITTER

The basic television Broadcast transmitter block diagram is shown in figure (a). The block diagram can be broadly divided into two separate section Read more about TV - TELEVISION TRANSMITTER

TRANSMISSION LINE

Co-axial Cable

Transmission line is defined as the path of carrying alternating electrical energy from source to load. For example the wire used between T.V antenna and television set or the wire used between transmitter antenna and transmitter are known as transmission

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