Skip to main content

Menu

Home ๐Ÿ“˜ Wireless Communication (Main Page) Constellation Diagrams BER vs SNR GMSK MSK Channel Impulse Response Modulation Schemes MIMO Technology OFDM MATLAB Projects Contact
Login Try App

MATLAB Code for Pulse Amplitude Modulation (PAM) and Demodulation


Pulse Amplitude Modulation (PAM) & Demodulation

Pulse Amplitude Modulation (PAM) & Demodulation of an Analog Message Signal

MATLAB Script

clc;
clear all;
close all;
fm = 10; % frequency of the message signal
fc = 100; % frequency of the carrier signal
fs = 1000 * fm; % sampling frequency (100 kHz)
t = 0:1/fs:1;
m = 1 * cos(2 * pi * fm * t);
c = 0.5 * square(2 * pi * fc * t) + 0.5;
s = m .* c;

subplot(4,1,1);
plot(t,m);
title('Message signal');
xlabel('Time');
ylabel('Amplitude');

subplot(4,1,2);
plot(t,c);
title('Carrier signal');
xlabel('Time');
ylabel('Amplitude');

subplot(4,1,3);
plot(t,s);
title('Modulated signal');
xlabel('Time');
ylabel('Amplitude');

% Demodulation
d = s .* c;
filter = fir1(200,fm/fs,'low');
original_t_signal = conv(filter,d);
t1 = 0:1/(length(original_t_signal)-1):1;

subplot(4,1,4);
plot(t1,original_t_signal);
title('Demodulated signal');
xlabel('Time');
ylabel('Amplitude');

web('https://www.salimwireless.com/search?q=pulse%20amplitude%20modulation', '-browser');

Output

PAM analog modulation MATLAB output

Another Code for Pulse Amplitude Modulation and Demodulation of an Analog Message Signal

MATLAB Script

clc;
clear;
close all;

% Parameters
messageFrequency = 2;
carrierFrequency = 20;
samplingFrequency = 1000;
duration = 1;
A = 1;

% Time vector
t = 0:1/samplingFrequency:duration;

% Message signal
messageSignal = A * sin(2 * pi * messageFrequency * t);

% Carrier signal
carrierSignal = A * square(2 * pi * carrierFrequency * t);

% PAM signal
pamSignal = messageSignal .* (carrierSignal > 0);

% Plotting
figure;
subplot(3,1,1); plot(t, messageSignal); title('Message Signal');
subplot(3,1,2); plot(t, carrierSignal); title('Carrier Signal');
subplot(3,1,3); plot(t, pamSignal); title('PAM Signal');

web('https://www.salimwireless.com/search?q=pulse%20amplitude%20modulation', '-browser');

Pulse Amplitude Modulation (PAM) & Demodulation for Digital Data

% The code is written by SalimWireless.Com
clc;
clear;
close all;

% Parameters
M = 8;
numSymbols = 100;
Fs = 1000;
T = 1;

% Generate random data
data = randi([0 M-1], 1, numSymbols);

% PAM Modulation
pamLevels = linspace(-M + 1, M - 1, M);
modulatedSignal = pamLevels(data + 1);

% Create time vector
t = 0:1/Fs:T*numSymbols-1/Fs;

% Upsample and create PAM signal
upsampledSignal = zeros(1, length(t));
for i = 1:numSymbols
    upsampledSignal((i-1)*Fs+1:i*Fs) = modulatedSignal(i);
end

% Add noise
snr = 20;
noisySignal = awgn(upsampledSignal, snr, 'measured');

% PAM Demodulation
receivedSymbols = noisySignal(1:Fs:end);
demodulatedData = zeros(1, numSymbols);
for i = 1:numSymbols
    [~, demodulatedData(i)] = min(abs(receivedSymbols(i) - pamLevels));
end

% Plotting
figure;
subplot(4,1,1); stem(data); title('Original Data');
subplot(4,1,2); plot(t, upsampledSignal); title('Transmitted PAM Signal');
subplot(4,1,3); plot(t, noisySignal); title('Received Noisy PAM Signal');
subplot(4,1,4); stem(demodulatedData); title('Demodulated Data');
grid on;

disp('Original Data:'); disp(data);
disp('Demodulated Data:'); disp(demodulatedData);

web('https://www.salimwireless.com/search?q=pulse%20amplitude%20modulation', '-browser');

Output

PAM digital modulation MATLAB output

Simulation Results for Comparison of PAM, PWM, PPM, DM, and PCM

Message Signal Simulation
PWM Signal Simulation
PPM Signal Simulation
PCM Signal Simulation
PWM | PPM | DM | Quantization | PCM
Explore Signal Processing Simulations

Further Reading

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

People are good at skipping over material they already know!

View Related Topics to







Contact Us

Name

Email *

Message *

Popular Posts

OFDM Symbols and Subcarriers Explained

This article explains how OFDM (Orthogonal Frequency Division Multiplexing) symbols and subcarriers work. It covers modulation, mapping symbols to subcarriers, subcarrier frequency spacing, IFFT synthesis, cyclic prefix, and transmission. Step 1: Modulation First, modulate the input bitstream. For example, with 16-QAM , each group of 4 bits maps to one QAM symbol. Suppose we generate a sequence of QAM symbols: s0, s1, s2, s3, s4, s5, …, s63 Step 2: Mapping Symbols to Subcarriers Assume N sub = 8 subcarriers. Each OFDM symbol in the frequency domain contains 8 QAM symbols (one per subcarrier): Mapping (example) OFDM symbol 1 → s0, s1, s2, s3, s4, s5, s6, s7 OFDM symbol 2 → s8, s9, s10, s11, s12, s13, s14, s15 … OFDM sym...
Read more

BER vs SNR for M-ary QAM, M-ary PSK, QPSK, BPSK, ...

๐Ÿ“˜ Overview of BER and SNR ๐Ÿงฎ Online Simulator for BER calculation of m-ary QAM and m-ary PSK ๐Ÿงฎ MATLAB Code for BER calculation of M-ary QAM, M-ary PSK, QPSK, BPSK, ... ๐Ÿ“š Further Reading ๐Ÿ“‚ View Other Topics on M-ary QAM, M-ary PSK, QPSK ... ๐Ÿงฎ Online Simulator for Constellation Diagram of m-ary QAM ๐Ÿงฎ Online Simulator for Constellation Diagram of m-ary PSK ๐Ÿงฎ MATLAB Code for BER calculation of ASK, FSK, and PSK ๐Ÿงฎ MATLAB Code for BER calculation of Alamouti Scheme ๐Ÿงฎ Different approaches to calculate BER vs SNR What is Bit Error Rate (BER)? The abbreviation BER stands for Bit Error Rate, which indicates how many corrupted bits are received (after the demodulation process) compared to the total number of bits sent in a communication process. BER = (number of bits received in error) / (total number of tran...
Read more

Constellation Diagrams of ASK, PSK, and FSK

๐Ÿ“˜ Overview of Energy per Bit (Eb / N0) ๐Ÿงฎ Online Simulator for constellation diagrams of ASK, FSK, and PSK ๐Ÿงฎ Theory behind Constellation Diagrams of ASK, FSK, and PSK ๐Ÿงฎ MATLAB Codes for Constellation Diagrams of ASK, FSK, and PSK ๐Ÿ“š Further Reading ๐Ÿ“‚ Other Topics on Constellation Diagrams of ASK, PSK, and FSK ... ๐Ÿงฎ Simulator for constellation diagrams of m-ary PSK ๐Ÿงฎ Simulator for constellation diagrams of m-ary QAM BASK (Binary ASK) Modulation: Transmits one of two signals: 0 or -√Eb, where Eb​ is the energy per bit. These signals represent binary 0 and 1.    BFSK (Binary FSK) Modulation: Transmits one of two signals: +√Eb​ ( On the y-axis, the phase shift of 90 degrees with respect to the x-axis, which is also termed phase offset ) or √Eb (on x-axis), where Eb​ is the energy per bit. These signals represent binary 0 and 1.  BPSK (Binary PSK) Modulation: Transmits one of two signals...
Read more

Coherence Bandwidth and Coherence Time

๐Ÿงฎ Coherence Bandwidth ๐Ÿงฎ Coherence Time ๐Ÿงฎ MATLAB Code s ๐Ÿ“š Further Reading Coherence Bandwidth Coherence bandwidth is a concept in wireless communication and signal processing that relates to the frequency range over which a wireless channel remains approximately constant in terms of its characteristics. Coherence bandwidth is inversely related to the delay spread time (e.g., RMS delay spread). The coherence bandwidth is related to the delay spread of the channel, which is a measure of the time it takes for signals to traverse the channel due to multipath. The two are related by the following approximation: Coherence Bandwidth ≈ 1/(delay spread time) Or, Coherence Bandwidth ≈ 1/(root-mean-square delay spread time) (Coherence bandwidth in Hertz) For instance, if the root-mean-square delay spread is 500 ns (i.e., {1/(2*10^6)} seconds), the coherence bandwidth is approximately 2 MHz (1 / 500e-9) in ...
Read more

UGC NET Electronic Science Previous Year Question Papers

Home / Engineering & Other Exams / UGC NET 2022: Previous Year Question Papers ...   NET | GATE | ESE | UGC-NET (Electronics Science, Subject code: 88 ) UGC Net Electronic Science Questions Paper With Answer Key Download Pdf [December 2024] UGC Net Electronic Science Questions Paper With Answer Key Download Pdf [June 2024] UGC Net Electronic Science Questions Paper With Answer Key Download Pdf [December 2023] UGC Net Electronic Science Questions Paper With Answer Key Download Pdf [June 2023] UGC Net Electronic Science Questions Paper With Answer Key Download Pdf [December 2022]  UGC Net Electronic Science Questions Paper With Answer Key Download Pdf [June 2022]   UGC Net Electronic Science Questions Paper With Answer Key Download Pdf [December 2021] UGC Net Electronic Science Questions With Answer Key Download Pdf [June 2020] UGC Net Electronic Science Questions With Answer Key Download Pdf [December 2019] UGC Net Electronic Science Questions With Answer...
Read more

Online Simulator for ASK, FSK, and PSK

Try our new Digital Signal Processing Simulator!   Start Simulator for binary ASK Modulation Message Bits (e.g. 1,0,1,0) Carrier Frequency (Hz) Sampling Frequency (Hz) Run Simulation Simulator for binary FSK Modulation Input Bits (e.g. 1,0,1,0) Freq for '1' (Hz) Freq for '0' (Hz) Sampling Rate (Hz) Visualize FSK Signal Simulator for BPSK Modulation ...
Read more

Bartlett Method in MATLAB

Steps to calculate Spectral power density using Bartlett Method 'M' is the length of each segment for the Bartlett method, set to 100 samples. 'K' is the number of segments obtained by dividing the total number of samples N by the segment length 'M'. psd_bartlett_broadband is initialized to store the accumulated periodogram. For each segment k, x_k extracts the k-th segment of the broadband signal. P_k computes the periodogram of the k-th segment using the FFT. The periodograms are accumulated and averaged over all segments. The PSD is plotted in dB/Hz by converting the power values to decibels using 10 * log10.   MATLAB Script clc; clear; close all; % Parameters fs = 1000; % Sampling frequency t = 0:1/fs:1-1/fs; % Time vector N = length(t); % Number of samples % Generate synthetic broadband ARMA process arma_order = [2, 2]; % ARMA(p,q) order a = [1, -0.75, 0....
Read more

Pulse Position Modulation (PPM)

Pulse Position Modulation (PPM) is a type of signal modulation in which M message bits are encoded by transmitting a single pulse within one of 2แดน possible time positions within a fixed time frame. This process is repeated every T seconds , resulting in a data rate of M/T bits per second . PPM is a form of analog modulation where the position of each pulse is varied according to the amplitude of the sampled modulating signal , while the amplitude and width of the pulses remain constant . This means only the timing (position) of the pulse carries the information. PPM is commonly used in optical and wireless communications , especially where multipath interference is minimal or needs to be reduced. Because the information is carried in timing , it's more robust in some noisy environments compared to other modulation schemes. Although PPM can be used for analog signal modulation , it is also used in digital communications where each pulse position represents a symbol or bit...
Read more