MATLAB Code for Delta Modulation (DM) and Demodulation

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• 🧮 MATLAB Code
• 🧮 Other Pulse Modulation Techniques (e.g., PWM, PPM, DM, and PCM)
• 📚 Further Reading

 

MATLAB Script 

clc;
clear all;
close all;

fs = 10000;
fm = 100;
t = 0:1/fs:1000/fs; % Time Duration = 1000/10000 = 0.1 second
x = 5*sin(2*pi*100*t); % Define Message Signal with peak voltage 5V and frequency 100Hz

plot(t, x);
hold on

y = [0]; % Output DM signal i.e. stream of 1 or 0
xr = 0; % Output of Integrator i.e. staircase approximation; initial value = 0
del = 0.4; % Stepsize

for i = 1:length(x)-1
if xr(i) <= x(i) % If current sample greater than the previous values or output of the integrator, output of DM = 1
d = 1;
xr(i+1) = xr(i) + del; % Staircase approximated value
else
d = 0;
xr(i+1) = xr(i) - del; % If current sample less than the previous values or output of the integrator, output of DM = 0
end
y = [y d];
end

stairs(t, xr); % Show the staircase approximated signal
title('Staircase Approximated Signal');
hold off

MSE = sum((x - xr).^2) / length(x); % Mean Squared Error (MSE)
disp(['Mean Squared Error (MSE): ', num2str(MSE)]);

figure;

% Delta Modulation
subplot(3, 1, 1);
plot(t,y); % Show the staircase approximated signal
title('Delta Modulated Signal');

% Delta Demodulation
subplot(3, 1, 2);
y_demod = [0];
xr_demod = 0;

for i = 2:length(y)
if y(i) == 1
xr_demod = xr_demod + del;
else
xr_demod = xr_demod - del;
end
y_demod = [y_demod xr_demod];
end

plot(t, y_demod);
title('Delta Demodulated Signal (Before Filtering)');

% Apply Low-Pass Filter
filter_order = 20;
lowpass_filter = fir1(filter_order, fm/(fs/2), 'low');
filtered_demod_signal = filter(lowpass_filter, 1, y_demod);

% Plot the filtered demodulated signal
subplot(3, 1, 3);
plot(t, filtered_demod_signal);
title('Filtered Demodulated Signal');

 

Output 

 

 

 

 

Copy the MATLAB Code from here

 

clc; clear all; close all; fs = 10000; fm = 100; t = 0:1/fs:1000/fs; % Time Duration = 1000/10000 = 0.1 second x = 5*sin(2*pi*100*t); % Define Message Signal with peak voltage 5V and frequency 100Hz plot(t, x); hold on y = [0]; % Output DM signal i.e. stream of 1 or 0 xr = 0; % Output of Integrator i.e. staircase approximation; initial value = 0 del = 0.4; % Stepsize for i = 1:length(x)-1 if xr(i) <= x(i) % If current sample greater than the previous values or output of the integrator, output of DM = 1 d = 1; xr(i+1) = xr(i) + del; % Staircase approximated value else d = 0; xr(i+1) = xr(i) - del; % If current sample less than the previous values or output of the integrator, output of DM = 0 end y = [y d]; end stairs(t, xr); % Show the staircase approximated signal title('Staircase Approximated Signal'); hold off MSE = sum((x - xr).^2) / length(x); % Mean Squared Error (MSE) disp(['Mean Squared Error (MSE): ', num2str(MSE)]); figure; % Delta Modulation subplot(3, 1, 1); plot(t,y); % Show the staircase approximated signal title('Delta Modulated Signal'); % Delta Demodulation subplot(3, 1, 2); y_demod = [0]; xr_demod = 0; for i = 2:length(y) if y(i) == 1 xr_demod = xr_demod + del; else xr_demod = xr_demod - del; end y_demod = [y_demod xr_demod]; end plot(t, y_demod); title('Delta Demodulated Signal (Before Filtering)'); % Apply Low-Pass Filter filter_order = 20; lowpass_filter = fir1(filter_order, fm/(fs/2), 'low'); filtered_demod_signal = filter(lowpass_filter, 1, y_demod); % Plot the filtered demodulated signal subplot(3, 1, 3); plot(t, filtered_demod_signal); title('Filtered Demodulated Signal'); 

 

Read more about

1.  Pulse Amplitude Modulation (PAM) and Demodulation
2. Pulse Width Modulation (PWM) and Demodulation
3. Pulse Position Modulation (PPM) and Demodulation
4. Delta Modulation and demodulation
5. Pulse Code Modulation (PCM)
6. Quantization Signal to Noise Ration (Q-SNR)
7. MATLAB Code for Pulse Amplitude Modulation and Demodulation
8. MATLAB Code for Pulse Width Modulation and Demodulation
9. MATLAB Code for Pulse Code Modulation (PCM) and demodulation