%本程序完成符號速率估計
clear all;
clc
N=1000;
M=2;
fs=2e6;
R=2e5;
% fc=1;
Nu=2048;
f=fs*(0:(Nu/2-1))/Nu;
% y=pqmod(M,N,1,fs,R);
x=pqmod(M,N,1,fs,R)';
x=awgn(x,25,'measured');
t=0:1/fs:(N/R-1/fs);
figure(1)
plot(t,x)
figure(2)
y=abs(fft(x,Nu));
y=10*log10(y);
f=fs*(0:Nu/2-1)/Nu;
plot(f,y(1:Nu/2))

tal=0.5;
ndelay=tal*fs/R;
% ndelay=10;
x1=x(1:(end-ndelay));
x_delay=x((1+ndelay):end);
xx=x1.*x_delay;
%計算功率譜密度
h=spectrum.welch;
h=spectrum.periodogram;
figure(3)
psd(h,xx,'Fs',fs)