xiaobo_psk.m

基于二次小波变换的psk信号符号率的估计

clear all;
close all;
format long;
Fc=40000;
Fs=200000; 
t=0:1/Fs:1;
Fb=1000;
Tb=1/Fb;
M=4;
N=100;
A=1;
x=0; 
SNR=20;
h=waitbar(0,'please wait');
for i=1:N
    waitbar(i/N)
    a(i)=(2*pi/M)*round((M-1)*rand(1));
    x=x+a(i)*(rectpuls(t-i*Tb,Tb)); 
end
close(h)
s=A*exp(j*(2*pi*t*Fc+x));
s1=awgn(s,SNR);
figure(1)
subplot(211)
plot(t,s1);axis([0 0.1 0 4])
subplot(212)
plot(t,real(s1));axis([0 0.1 -4 4])
figure(2)
subplot(211)
q=abs(cwt(s1,4,'haar'));
plot(t*100,q);axis([0 10 0 5]);grid
subplot(212)
q1=abs(cwt(q,4,'haar'));
plot(t*100,q1);axis([0 10 0 5]);grid
figure(3)
n=400000;
step=Fs/n;
n1=0:step:Fs/4-step;
M=n;
W=exp(-j*2*pi/M);
A=1;
Y=abs(czt(q1,M,W,A));
plot(n1,Y(1:n/4));grid;xlabel('f/Hz');
ylabel('Magnitude');axis([0 4000 0 1000]);
[aa,ab]=max(Y(1000:3000));
ab=ab+999;
ac=n1(ab);