What is an Electronic Communication System?
Humans have a natural instinct to communicate with each other. We talk to each other using audio waves which are essentially electromagnetic waves. The frequency ranger of our audio signal is from 30 Hz to 3.4 KHz. Using this frequency we cannot communicate over long distances. In our day to day lives, we can communicate hardly up to 10 meters or so with each other. If we want to increase the distance of communication we have to put more energy and shout. Even this shouting will make the signal reach a few extra meters only.
What if we want to communicate over a few hundred or thousands of kilometers? Is it possible with our vocal cords only?
You guessed it right. Our vocal cords have a certain limitation to transmit the audio signal. Transmitting the audio signals directly beyond a few meters is beyond human capability. We need certain technological interventions to make it happen.
In today's world, we are using semiconductor electronics-based systems extensively to transmit signals from one place/person/device to another place/person/device using electromagnetic waves. These systems are called Electronic Communication Systems.
Examples of Electronic Communication Systems are telegraph, telephone, mobile phone, pager, internet etc.
Electronic Communication System Block Diagram and Working
A typical block diagram for an Electronic Communication System may be as follows:
The main components of any Electronic Communication System are as follows:
Message Source: Message source may be any audio, video or data. Audio and Video signals are usually analog in nature. Data is a digital signal which originates from computer systems. Transmission of these message signals is prime objective of any communication system.
Input Transducer: The input signals such as voice, data or video; whatever we wish to transmit has to be in the form of an electrical signal. Only electrical signals can be transmitted over electronic communication systems. The input transducer is an electronic/electrical device used to convert the input signal in the form of an electrical signal such as voltage or current. For example, a microphone is used to convert an incoming voice signal in the form of an electrical signal.
Transmitter: Transmitter section comprises of modulating elements and amplifiers as per the requirement of the system. The transmitter is the section that applies the main concepts and algorithms of electronic communication to the incoming signals. The output of the transmitter is fed to an antenna in case of a wireless communication system. It is fed to the wired channel in case of a wired channel like optical fiber or coaxial cable.
Channel: Channel is the medium through which the signals sent by transmitter travels towards the destination. Depending of medium channel may be wired or wireless. In wired channels signal transmission takes place inside a bounded medium. A few examples of wired channels are telephone lines, optical fibers, copper cables, coaxial cables etc. In the case of wireless channel signal transmission takes place through the air. Few examples of wireless channels are microwave links, mobile phones, satellite communication etc. Signal degradation takes place inside the channel due to attenuation, distortion and noise. When the signal travels through long-distance, its power level decreases due to attenuation over the channel. Spurious signals get added in the form of noise signals. Because of these reasons signal faces distortion. We need to have proper mechanisms at the transmitter and receiver end to mitigate the effects of this noise and its implications otherwise it becomes very difficult to reproduce the originally transmitted signal at the receiver end.
Receiver: The receiver block does exactly the opposite processing to that of the transmitter. The signal received from the channel is filtered out for noise and unwanted signals. Then the demodulation of signals takes place. The demodulated signals are in the form of an electrical signal. These signals are fed to the output transducer.
Output Transducer: It translates the received signal into its original form i.e. from an electrical signal to its original form as it was before transmission.
Message Destination: It is an end-user that consumes the message or information.
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