Subject : Principle of Communication Engineering

Topic : Introduction to Electronic Communication

Difficulty : Medium

The elements of basic communication system are as follows

• Information or input signal
• Input Transducer
• Transmitter
• Communication channel or medium
• Noise
• Receiver

• Output Transducer

  

  Fig.1 Block diagram of Communication system

1. Information or input signal

• The communication systems have been developed for communicating useful information from one place to other

• The information can be in the form of sound signal like speech or music or it can be in the form of pictures.

2. Input Transducer

• The information in the form of sound, picture or data signals cannot the transmitted as it is.

• First it has to be converted into a suitable electrical signal.

• The input transducers commonly used in the communication systems are microphones, TV etc.

3. Transmitter

• The function of the transmitter block is to convert the electrical equivalent of the information to a suitable form

• It increases the power level of the signal. The power level should be increased in order to cover a large range. The transmitter consists of the electronics circuits such as amplifier, mixer, oscillator, and power amplifier.

4. Communication channel or medium

• The communication channel is the medium used for the transmission of electronic signals from one place to the another.

• The communication medium can be conducting wires, cables, optical fibres or free space. Depending upon the type of the communication medium, two types of the communication system will exist

  a. Wire communication or line communication

  b. Wireless communication or radio communication

5. Noise

• Noise is an unwanted electrical signal which gets added to the transmitted signal when it is travelling towards receiver.
• Due to noise, the quality of the transmitted information will degrade. One added the noise cannot be separated out from the information
• Hence noise is ab big problem in the communication systems.

6. Receiver

• The reception is exactly the opposite process of transmission. The received signal is amplified and demodulated and converted in a suitable form

• The receiver consists of the electronic circuits like mixer, oscillator, detector and amplifier.

7. Output Transducer

• It consists of the electrical signal at the output of the receiver back to the original form i.e. sound or TV pictures.

• The typical example of the output transducers are loud speakers, picture tubes etc.