%*************************************%
%            Daniell Methed           % 
%*************************************%
%產生信號序列
n=linspace(-pi,pi,128);
x=2*sin(n*40)+cos(n*100);
figure,plot(x);
title('Input Signal');
%信號補零并計算Ppw
y1=fft(x,1024);
y2=conj(y1);
Ppw=y1.*y2/1024;
figure,plot(Ppw);
grid on
%對Ppw補零并計算PDw
Pp=zeros(1,64);
Ppw=[Pp,Ppw,Pp];
for k=1+64:1024+64
    PD1(k-64)=0;
    for j=k-64:k+64
        PD1(k-64)=PD1(k-64)+Ppw(j);
    end
    PDw(k-64)=PD1(k-64)/129;
end
%繪圖
figure,plot(PDw);
grid on
title('Daniell');