THE CHANNELS AND THE NOISE

The term channel means the medium through which the message travels from transmitter to receiver. This means a channel provides physical connection between the transmitter and the receiver. There are two types of channel:

1. Point to point channel

Point to point channel are the wire lines, microwaves links and optical fibers.

2. Broadcast channel

Broadcast channel provides a capability while simultaneously from a signal transmitter. An example of broadcast channel is a satellite in Geo stationary orbit. During the process of transmission and reception the signal gets distorted due to noise introduced in the system. Noise is an unwanted signal. Noise is always random in character and it may interfere with signal at any point in the communication system.

Receiver:

     The main function of the receiver is to reproduce the message signal in electrical form from the distorted received signal. This reproduction of the original signal is accomplished by a process known as the demodulation or detection. Demodulation is the reverse process or modulation carried out in transmitter.

Destination:

      Destination is the final stage which is used to convert an electrical message signal into its original form. For example in radio broadcasting, the destination is a loudspeaker which works as a transducer i.e. it converts the electrical signal in the form of original sound signal.