psk.m

这是基于MATLAB的数字调相技术编程,包括对调制解调过程的编程以及其有效性和可靠性分析

clear all;
close all;

n=1:8192;
m=1:128;x(n)=randint(1,8192,2);x=[x(n)]';
y(n)=zeros(1,8192);z(m)=zeros(1,128);
for n=1:8192
    for m=1:128
    if n==64*m-63
    z(m)=x(n);  
    if m==ceil(n/64)
        y([(64*m-63):(64*m)]')=z(m);
    end
end
end
end
n=1:8192;
rm2=y(n);
x2=rm2;
%n=[1:(2^13)];
%%%%%%%%%%%%%%%%%PSK调制%%%%%%%%%%%%%%%%%%%%%%
x0=cos(n.*1.0*1.6);
x1=cos(n.*1.0*1.6+pi);
x=x1.*x2+x0.*~x2;
b=blackman(2^13);
X=b'.*x;
x3=[ones(1,64) zeros(1,8128)];
y1=X(1:(2^13)); y4=x0.*x3+x1.*~x3;
Y1=fft(y1,(2^13));magY1=abs(Y1(1:1:(2^12)+1))/(200); %求基带信号的FFT
Y4=fft(y4,(2^13));magY4=abs(Y4(1:1:(2^12)+1))/(37);  %求调制后脉冲信号的FFT
k1=0:(2^12);w1=(2*pi/(2^13))*k1;
u=(2*w1/pi)*1e9;

figure(1)
subplot(2,1,1);
plot(u,magY1,'b',u,magY4,'r');grid
title('PSK已调信号功率谱');axis([4e8,1.6e9,0,1.1])
X2=b'.*x2;
y2=X2(1:(2^13));
Y2=fft(y2,(2^13));magY2=abs(Y2(1:1:(2^12)+1))/(200)+eps;%基带信号的FFT
k1=0:(2^12);w1=(2*pi/(2^13))*k1;
u=(2*w1/pi)*1e9;
Y3=fft(x3,(2^13));magY3=abs(Y3(1:1:(2^12)+1))/(37)+eps;%脉冲信号的FFT
subplot(2,1,2);semilogy(u,magY2,'b',u,magY3,'r');grid
title('基带信号功率谱');axis([0,1.2e9,3e-2,3]);

figure(2)
subplot(2,1,1);plot(n,x2);title('基带信号');
axis([0,640,-0.2,1.2]);grid
subplot(2,1,2);plot(n,x);title('PSK已调信号');
axis([0,640,-1.2,1.2]);grid