Name: Sources of Electromagnetic Waves
Uploaded: 2019-07-19
Duration: 5 min 12 s
Description: Can you name some sources of electromagnetic waves by looking around you? You will learn about the different sources of electromagnetic waves

Question

Why modulation is required? Name the types of modulation. Describe various aspects of AM.

Accepted Answer

The energy associated with the audio signals is normally less. So it has to be combined with electromagnetic waves, before transmission. For transmitting the signal, the length of the antenna required is proportional to the wavelength of the signal, which is very large for audio signals. So high-frequency radio waves are used for transmission. Modulation is the process by which the characteristics of a higher frequency wave, called the carrier wave, are changed in accordance with the signal.

The characteristics of a wave are mainly the amplitude, the frequency, and the phase. Therefore, there are three different possible types of modulations, depending upon what property is modulated.
i) Amplitude modulation
ii) Frequency modulation
iii) Phase modulation.

Amplitude modulation is obtained by changing the amplitude of the carrier wave. Most of the power of the modulated wave is carried by the carrier wave in amplitude modulation. That is why it is mostly useless. The side-band power carries the useful section of the signal. But the power depends on the modulation index.

Why modulation is required? Name the types of modulation. Describe various aspects of AM.

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