You have to transmit Data Sequence 11100010 with transmission bit rate 1000000 through QPSK. Write a Matlab code and a) Generate data sequence and all the above mentioned wave

clear all

close all

Data_Seq=[1,1,1,0,0,0,1,0]

stem(Data_Seq)

bitrate= 1000000;

SR=1/bitrate;

ylim([-1 1])

t=0:0.01:length(Data_Seq)

Data_Seq2=[1,1,1,-1,-1,-1,1,-1]

stem(Data_Seq2)

A = Data_Seq2(1:2:end,:) %

B = Data_Seq2(2:2:end,:)

stem(A)

even = Data_Seq(2:2:end);

odd = Data_Seq(1:2:end);

stem(even)

// i Want to seperate even and odd signal but not undrstanding how to plot

Answer 1

[Shashi Kiran]

Hi Ali,

I understand that you want to separate the even and odd components of the data sequence [1, 1, 1, 0, 0, 0, 1, 0] and plot them.

Here is how you can achieve that in MATLAB using stem and subplot functions:

clear;
% Define the data sequence
Data_Seq = [1, 1, 1, 0, 0, 0, 1, 0];

% Plot the original data sequence
figure;
subplot(4, 1, 1);
stem(Data_Seq, 'filled');
title('Original Data Sequence');
xlabel('Bit Index');
ylabel('Bit Value');
ylim([-0.5 1.5]);

% Define parameters
bitrate = 1000000; 
SR = 1/bitrate; 

% Convert binary data to bipolar format for QPSK
Data_Seq2 = 2*Data_Seq - 1;

% Separate the data into even and odd sequences
even = Data_Seq2(2:2:end); % Even indexed bits
odd = Data_Seq2(1:2:end);  % Odd indexed bits

% Plot the bipolar data sequence
subplot(4, 1, 2);
stem(Data_Seq2, 'filled');
title('Bipolar Data Sequence');
xlabel('Bit Index');
ylabel('Amplitude');
ylim([-1.5 1.5]);

% Plot the odd sequence
subplot(4, 1, 3);
stem(odd, 'filled');
title('Odd Indexed Sequence (In-phase I)');
xlabel('Symbol Index');
ylabel('Amplitude');
ylim([-1.5 1.5]);

% Plot the even sequence
subplot(4, 1, 4);
stem(even, 'filled');
title('Even Indexed Sequence (Quadrature Q)');
xlabel('Symbol Index');
ylabel('Amplitude');
ylim([-1.5 1.5]);

Refer to the following documentations for more details about the functions:

1. subplot: https://www.mathworks.com/help/matlab/ref/subplot.html
2. stem: https://www.mathworks.com/help/matlab/ref/stem.html

Hope this solves your query.