Am Modulation Matlab

How To Articles

As a technical enthusiast with a passion for digital signal processing, I have always been fascinated by the world of amplitude modulation (AM) and its applications. In this article, I will explore AM modulation using MATLAB and provide detailed insights into its theory and implementation.

Understanding Amplitude Modulation

Amplitude modulation is a modulation technique used in telecommunications to transmit information by varying the amplitude of a carrier wave based on the message signal. The carrier wave is a high-frequency sine wave, and the message signal contains the information we want to transmit.

AM modulation involves three components:

  • Carrier signal: This is the high-frequency sine wave that carries the modulated information.
  • Message signal: This is the signal that carries the information we want to transmit. It is usually a low-frequency audio signal.
  • Modulated signal: This is the result of combining the carrier and message signals. The modulated signal’s amplitude varies in accordance with the message signal.

Now that we have a basic understanding of AM modulation, let’s dive into MATLAB and see how we can implement it.

Implementing AM Modulation in MATLAB

MATLAB provides a powerful set of functions for signal processing, making it an excellent choice for implementing AM modulation. To start, we need to generate the carrier and message signals.

carrier_frequency = 1000; % Frequency of the carrier signal in Hz
message_frequency = 100; % Frequency of the message signal in Hz
sampling_frequency = 10000; % Sampling frequency in Hz
duration = 1; % Duration of the signals in seconds

t = 0:(1/sampling_frequency):duration; % Time vector

% Generate the carrier signal
carrier_signal = cos(2*pi*carrier_frequency*t);

% Generate the message signal
message_signal = sin(2*pi*message_frequency*t);

After generating the carrier and message signals, we can proceed with the modulation process. In AM modulation, we multiply the carrier signal by the message signal to obtain the modulated signal.

modulated_signal = carrier_signal .* message_signal;

Once we have the modulated signal, we can plot it to visualize the effect of AM modulation:

plot(t, carrier_signal);
title('Carrier Signal');
xlabel('Time (s)');

plot(t, message_signal);
title('Message Signal');
xlabel('Time (s)');

plot(t, modulated_signal);
title('Modulated Signal');
xlabel('Time (s)');

Running the code above will generate a plot with three subplots showing the carrier signal, message signal, and modulated signal, respectively.


Amplitude modulation is a fundamental modulation technique used in telecommunications, and MATLAB provides a versatile platform for implementing it. By generating the carrier and message signals and multiplying them, we can obtain the modulated signal. This article has provided a comprehensive overview of AM modulation implementation in MATLAB, allowing us to transmit information effectively using varying amplitude. So, go ahead and explore the fascinating world of AM modulation with MATLAB!