clear all
for k=1:20
fname=sprintf('D:\\study\\音頻采樣\\noise22050hz\\%d.wav',k);
x=wavread(fname);
x=x(:,1);
[c,l]=wavedec(x,3,'db4');
ca=appcoef(c,l,'db4',3);%近似系數
x=ca;
enframex=enframe(x,128,64);%對信號x分幀處理，每幀有128個采樣點，相鄰幀之間有50%的疊加率
[row,col]=size(enframex);%返回行，列，每一行代表一幀，每一列表示1到128個采樣點
 A=abs(enframex).^2;
 for j=1:row
   energy(j)=sum(A(j,:));
 end
for j=1:row
   sum1(j)=0;
   for i=1:col
   sum1(j)=sum1(j)+i*A(j,i);
   end
end
centroid=sum1./energy;
for j=1:row
    sum2(j)=0;
    for i=1:col
        sum2(j)=sum2(j)+(i-centroid(j)).^2*A(j,i);
    end
end
 bandwidth=sum2./energy;
noisecentroidjuzhi(1,k)=mean(centroid);
noisebandwidthjuzhi(1,k)=mean(bandwidth);
end
noisecentroidjuzhi
noisebandwidthjuzhi