Subject : Principle of Communication Engineering

Topic : Introduction to Electronic Communication

Difficulty : Low

• Electromagnetic radiation is a form of energy in which electric and magnetic fields are mutually perpendicular to each other and these two electric and magnetic fields are perpendicular to the direction of wave propagation. It exhibits wave like behaviour when it is travelling through space.

• Electromagnetic waves can be classified and arranged according to their various wavelengths/frequencies; this classification is known as the electromagnetic spectrum. The following FIG.1 shows EMspectrum, which consists of all the types of electromagnetic radiation that exist in our universe.

  

  Fig.1 Complete electromagnetic (EM) spectrum

• Radio waves are mainly used for fixed and mobile radio communication.

• Radio waves have the wavelength ranging from 1mm to 100km and frequencies ranging from 3KHZ to 300GHZ.

• Fig.2 shows table of radiofrequency spectrum