[matlab] matlab simulates digital bandpass transmission systems - QPSK and OQPSK systems

Catalog

1、QPSK and OQPSK System

2、 wave form

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1、QPSK and OQPSK System

clear all;
clc;
close all;
fc = 5; % Carrier frequency 
N_sample = 16;
N_num = 100; % Number of symbols 
dt = 1/(fc*N_sample);
Ts = 1; % Symbol interval 
t = 0:dt:(N_num*Ts-dt);
T = dt*length(t);
d1 = sign(randn(1,N_num)); % Bipolar code 
d2 = sign(randn(1,N_num)); % Bipolar code 
gt = ones(1,fc*N_sample); %NRZ  wave form 
%QPSK  Modulation mode 
s1 = sigexpand(d1,fc*N_sample);
s2 = sigexpand(d2,fc*N_sample);
b1 = conv(s1,gt); % Bipolar  NRZ  wave form 
b2 = conv(s2,gt); % Bipolar  NRZ  wave form 
s1 = b1(1:length(s1)); % In phase baseband signal 
s2