Amplitude Modulation (AM) Explained

Опубликовано: 22 Июль 2020
на канале: ALL ABOUT ELECTRONICS
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In this video, the Amplitude Modulation (AM) is Explained in detail.
An watching this video, you will learn the following topics:

0:00 Introduction to Amplitude Modulation (AM)
3:07 What is Envelope of the AM signal and brief intro to Envelope Detection
5:33 What is the Modulation Index?
11:54 Modulation Index for Tone Modulation
14:26 Frequency Spectrum of AM signal
16:52 Carrier Power and Sideband Power of AM signal
21:05 Transmission Efficiency of AM signal

Amplitude Modulation:
In Amplitude Modulation, the amplitude of the carrier signal changes according to the message signal.

Modulation Index:
The modulation index defines, to what extent the carrier signal gets modulated by the message signal.

For the asynchronous demodulation of the AM signal (using the envelope detection), the modulation index of the AM signal should be less than or equal to 1.
If the modulation index is greater than 1 (overmodulation), there will be distortion in the demodulated signal.

Frequency Spectrum of AM signal:

In this video, the frequency spectra of the AM signal is explained for the tone modulation as well as for the general message signal.
If the bandwidth of the message signal is B, then after the modulation, the required bandwidth will be 2B. (The Amplitude Modulation requires two times the bandwidth of the modulating signal)

Carrier and Sideband Power:

In Amplitude Modulation, a lot of transmitted power is wasted for transmitting the carrier signal. (Even though it does not carry any information)

For the tone modulation, the total transmitted power
Pt = Pc ( 1 + µ^2/2)
Where Pc - Carrier Power and µ - Modulation Index

Transmission Efficiency of AM signal:
For tone modulation,
Transmission Efficiency (%) = Useful power / Total power = µ^2 / ( 2 + µ^2)

Other Useful videos related to Communication:

1) What is Modulation? Types of Modulation


2) Introduction to Analog and Digital Communication


This video will be useful to all students of science and engineering in understanding the Amplitude Modulation (AM).


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