Question

What are carrier waves? Why do we need the carrier waves of high frequency for distant communication?

Answer 1

Carrier waves are electromagnetic waves that travel with the velocity of light and do not require a material medium to propagate.

Complete step by step answer:
A carrier wave is an electromagnetic wave that is modulated in amplitude or frequency to carry a signal. As a carrier wave is an electromagnetic wave, it travels with the velocity of light and with constant amplitude. It is used to carry signals from one location to another on the surface of earth. We need the carrier waves of high frequency for distant communication because high frequency carrier waves travel with the speed of light and do not require a material medium to propagate. So, such types of waves are not obstructed by the earth's atmosphere.

Note:
An electric field changing with time in a region produces a magnetic field in that region. The variations in electric field and magnetic field are perpendicular to each other. These disturbances have the properties of waves and can travel in space even without any material medium and are called electromagnetic waves. There is a need for transmission of electromagnetic waves at high frequencies. This is achieved by the process of modulation, wherein we superimpose the audio frequency waves on a high frequency carrier wave. The resultant wave is called the modulating wave. The carrier wave may be a continuous or sinusoidal wave or can be a pulse, which is discontinuous.