oqpsk.m

这是有关matlab结课作业

clear all
close all
x=[1 1 -1 -1 -1 1 1 1];
x1=x(1:2:8);
x2=x(2:2:8);

t=[-1:0.01:7-0.01];
tt=length(t);
xx1=ones(1,800);
for i=1:tt
    if (t(i)>=-1 & t(i)<=1) | (t(i)>=5& t(i)<=7);
        xx1(i)=1;
    
    else xx1(i)=-1;
    end
end

t1=[0:0.01:8-0.01];
t2=0:0.01:7-0.01;
t3=-1:0.01:7.1-0.01;
t4=0:0.01:8.1-0.01;

tt1=length(t1);
xx2=ones(1,800);
for i=1:tt1
    if (t1(i)>=0 & t1(i)<=2) | (t1(i)>=4& t1(i)<=8);
        xx2(i)=1;
    
    else xx2(i)=-1;
    end
end


% ddd=fft(xx1);
% ddd0=fft(xx2);
% subplot(2,1,1);plot(t1,ddd);
% subplot(2,1,2);plot(t1,ddd0);

f=0:0.1:1;
xrc=0.5+0.5*cos(pi*f);

y1=conv(xx1,xrc)/5.5;
y2=conv(xx2,xrc)/5.5;

% ddd1=fft(y1);
% ddd2=fft(y2);
% figure
% subplot(2,1,1);plot(t2,ddd1);
% subplot(2,1,2);plot(t2,ddd2);


n0=randn(size(t2));

f1=1;
i=xx1.*cos(2*pi*f1*t);
q=xx2.*sin(2*pi*f1*t1);

I=i(101:800);
Q=q(1:700);

OQPSK=sqrt(1/2).*I+sqrt(1/2).*Q;

OQPSK_n=(sqrt(1/2).*I+sqrt(1/2).*Q)+n0;


n1=randn(size(t2));
i_rc=y1.*cos(2*pi*f1*t3);
q_rc=y2.*sin(2*pi*f1*t4);

I_rc=i(101:800);
Q_rc=q(1:700);
OQPSK_rc=(sqrt(1/2).*I_rc+sqrt(1/2).*Q_rc);
OQPSK_rc_n1=(sqrt(1/2).*I_rc+sqrt(1/2).*Q_rc)+n1;

figure(1)
subplot(6,1,1);plot(t3,i_rc);axis([-1 8 -1 1]);
subplot(6,1,2);plot(t4,q_rc);axis([-1 8 -1 1]);
subplot(6,1,3);plot(t2,OQPSK);axis([-1 8 -1 1]);
subplot(6,1,4);plot(t2,OQPSK_rc);axis([-1 8 -1 1]);
subplot(6,1,5);plot(t2,OQPSK_rc);axis([-1 8 -1 1]);
subplot(6,1,6);plot(t2,OQPSK_rc_n1);axis([-1 8 -1 1]);


% I_demo=OQPSK_rc_n1.*cos(2*pi*f1*t2);
% Q_demo=OQPSK_rc_n1.*sin(2*pi*f1*t2);
% 
% y1_demo=conv(I_demo,xrc);
% y2_demo=conv(Q_demo,xrc);
% 
% 
% 
% x1_recove=ones(1,900);
% x2_recove=ones(1,900);
% 
% for i=1:100:900
%     if sum(y1_demo(i:i+99))>100
%         x1_recove(i:i+99)=1;
%     elseif sum(y1_demo(i:i+99))<-100
%         x1_recove(i:i+99)=-1;
%     else x1_recove(i:i+99)=0;
%     end
% end
% 
% for i=1:100:900
%     if sum(y2_demo(i:i+99))>100
%         x2_recove(i:i+99)=1;
%     elseif sum(y2_demo(i:i+99))<-100
%         x2_recove(i:i+99)=-1;
%     else x2_recove(i:i+99)=0;
%     end
% end




%subplot(2,1,1);plot(t,x1_recove);
%subplot(2,1,2);plot(t,x2_recove);
%figure
%subplot(2,1,1);plot(y1_demo);
%subplot(2,1,2);plot(y2_demo);