ASK Modulation using MATLAB: Code and Explanation

This document provides MATLAB source code for Amplitude Shift Keying (ASK) modulation, along with output plots and relevant mathematical equations.

Introduction to ASK Modulation

ASK modulation is a digital modulation technique where the amplitude of the carrier signal is varied according to the digital binary data (1 or 0).

• Binary logic-1 is represented by one level of carrier amplitude (A2).
• Binary logic-0 is represented by another level of carrier amplitude (A1).

Figure 1: ASK Modulation

As illustrated in Figure 1, the inputs are digital binary data and an analog carrier signal. The output is an analog ASK modulated signal.

ASK offers high bandwidth efficiency and a relatively simple receiver design.

See also: Difference between ASK, FSK, and PSK modulation types, and Advantages and Disadvantages of ASK Modulation.

ASK MATLAB Code

clear;
clc;

b = input('Enter the Bit stream \n ');
% b = [0 1 0 1 1 1 0];
n = length(b);
t = 0:.01:n;
x = 1:1:(n+1)*100;

for i = 1:n
    for j = i:.1:i+1
        bw(x(i*100:(i+1)*100)) = b(i);
    end
end

bw = bw(100:end);
sint = sin(2*pi*t);
st = bw.*sint;

subplot(3,1,1)
plot(t,bw)
grid on;
axis([0 n -2 +2])
title('Binary Waveform');
xlabel('Time');
ylabel('Amplitude');

subplot(3,1,2)
plot(t,sint)
grid on;
axis([0 n -2 +2])
title('Carrier Signal');
xlabel('Time');
ylabel('Amplitude');

subplot(3,1,3)
plot(t,st)
grid on;
axis([0 n -2 +2])
title('ASK Modulated Signal');
xlabel('Time');
ylabel('Amplitude');

Input and Output of ASK Modulation MATLAB Source Code

1. Provide Input: When prompted, enter the bit stream.

   

2. Press Enter: After entering the bit stream, press the “ENTER” key. You should get an output similar to the figure below.