In a communication system, the message signal can be voice, music, picture or computer data. All of these ‘signals’, have ‘different ranges of frequencies’. For example speech signals require a bandwidth of 2800 Hz, for commercial telephonic communication. To transmit music, an approximate bandwidth of 20 KHz is required video signals, for transmisstion of pictures, require 4.2 MHz of bandwidth. A T.V. signal (having both video and audio parts) usually has 6 MHz of bandwidth for transmission.
