"Communication is the act of transmission of information". Every living creature in the world experiences the need to impart or recive information almost continuously with others in the surrounding world. For communication to be successful, it is essential that the sender and the receiver understand a common language. Man has constantly made endeavours to improve the quality of communication with other human beings.
Languages and methods used in communication have kept evolving from prehistoric to modern time, to meet the growing demands in terms of speed and complexity of information. It would be worthwhile to look at the major milestones in events that promoted development in communication.
Modern communication has its roots in the 19th and 20th century in the work of scientists like J.C. Bose, F.B. Morse, G.Marconi and Alexander Graham Bell. The pace of development seems to have increased dramatically after the first half of the 20th century. We can hope to see many more accomplishments in the coming decades. The aim of this article is introduce the concept of communication, namely the mode of communication, the need for modulation, production and deduction of amplitude modulation.
Elements of a Communication System
Communication pervades all stages of life of all living creatures. Irrespective of its nature, every communication system has three essential elements- transmitter, medium/ channel and receiver. The block diagram shown in picture depicts the general from of communication system.
In a communication system, the transmitter is located at one place, the receiver is located at some other place (far or near) separate from the transmitter and the channel is the physical medium that connects them. Depending upon the type of communication system, a channel may be in if may be wireless. The purpose of the transmitter is to convert the massage signal produced by the source of information into a from suitable for transmission through the channel. If the output of the information source is non- electrical signal like a voice signal, a transducer converts it to electrical from before giving it as an input to the transmitter.
When a transmitted signal propagates along the channel it may get distorted due to channel imperfection. Moreover, noise adds to the transmitted signal 🚦 and the receiver receives a corrupted version of the transmitter signal. The receiver has the task of operating on the recived signal. It reconstructs a recognisable from of the original message signal for delivering it to the user of information.
There are two basic modes of communication:
- Point- to Point
- And broadcast
In point- to - point communication mode, communication takes place over a link between a single transmitter and a receiver. Telephony is an example of such a mode of communication. In corresponding to a single transmitter. Radio and television and examples of broadcast mode of communication.
