Communication is the process of exchanging the information. Communication may be at small or long distances, as we call to our friend, this is small distance communication, but if we make a call from one country to another country, or one city to another city, this is called long distance communication. But one thing is common to all types of communications that they have same basic parts or elements, which are very necessary in completion of successful communication. All electronic communications systems have Four basic elements. These elements are as below
- Communication channel or Medium
These basic elements are also called communication components. Because without one of these communication in incomplete. In most systems, a human generates a message that we call the information, or intelligence, signal. This signal is inputted to the transmitter which then transmits the message over the communications channels. The message is picked up by the receiver and is relayed to another human. Along the way, noise is added to the message in the communications channel. Noise is the general term applied to any interference that degrades the transmitted information. Let’s take a close look at each element of communication system.
Transmitter is the first solid element of communication system. The transmitter is collection of electronics components designed to convert the information into a signal suitable or transmission over a given communication medium. It may be as simple as a microphone or as complex as a microwave radio transmitter.
Communication channel comes after the transmitter, it is also main element of communication system. The communication channel is the medium by which the electronic signal is sent from one place to another. In this simplest form, the medium may simply be a pair of wires that carry a voice signal from a microphone to a headset. The communications medium may also be a fiber-optic cable or light pipe that carries the message on a light wave.
On the other hand, the medium may be wireless or radio. Radio is the broad general term applied to any form of wireless communication form one point to another. Radio makes use of the electromagnetic spectrum where signals are communicated from one point to another by converting them into electric and magnetic fields that propagate readily over long distances.
Although the medium supports the transmission of information, it also attenuates it. Any type of media degrades the signal and causes it to appear much lower in amplitude at the receiver. Considerable amplification of the signal, both at the transmitter and the receiver, is required for successful communication.
The receiver (RX) is another collection of electronic components and circuits that accept the transmitted message from the channel and convert it back into a form understandably by humans. Again it may be a simple earphone or a complex electronics receiver.
Noise is random, undesirable electric energy that enters the communication system via the communication medium and interferes with the transmitted messages. However, some noise is also produced in the receiver. Noise comes from the atmosphere (e.g from lighting which produces static ), from outer space where the sun and other stars emit various kinds of radiations that can interfere with communications, and from electrical interference created by manufactured equipment. The electric ignition systems of cars, electric motors, fluorescent lights, ad other types of equipments generate signals that can also interfere with the transmission of the messages.
Finally many electric components generate noise internally due to thermal agitation of the atoms. Although such noise signals are low level, they can often seriously interfere with the extremely low level signals that appear greatly attenuated at the receiver after being transmitted over a long distance. In some cases noise completely obliterates the message. At other times, ti simply causes interference, which, in turn, means some of the message is completely missed or misinterpreted.
Noise is one of the more serous problems of electrons communication. For the most part, it cannot be completely eliminated.