Monday, 4 May 2015

Computer Studies Made Simple : Bandwidth

 Bandwidth

This refers to amount of data that canbe transferred through a communication medium in one second.

The bandwidth of a digital signal is measured in bits/second or bytes per second.

Bandwidth of analog signal is measured in cycles/second or Hertz.

Baseband:

This is a communication technique in which digital signalas are placed on transmission line without a change in modulation.

It means that digital signals are transmitted directly over a transmission line.

It transmits only one signal at a time

Digital signals are commonly called baseband signals.


Spectrum of a baseband signal, energy E per unit frequency as a function of frequency f. The total energy is the area under the line.

Broadband

This is a technique to transmit large amounts of data such as voice and video over long distance.

It can send data by modulating each signal onto a different frequency.

It transmits several streams of data simultaneously using FDM Frequency Division Multiplexing technique.

FDM divides the bandwidth of a communication line into smaller frequency bandwidths.

Each part of the communication line canbe used for transmitting data separately.

Broadband is faster than Base band.

It is used for direct communication between very high speed computers such as mainframe computers,


It includes microwave,satellite,co-axial cable and fibre-optic media.


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