新建 文本文档 (3).txt

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[y,fs,b]=wavread('2.wav'); 
for m=513:1024 
   z(m-512)=y(m); 
end 
Y2=fft(z); 
Y2=abs(Y2); 
  
for m=1025:1536 
   z(m-1024)=y(m); 
end 
Y3=fft(z); 
Y3=abs(Y3); 
  
for m=1537:2048 
   z(m-1536)=y(m); 
end 
Y4=fft(z); 
Y4=abs(Y4); 
  
for m=2049:2560 
   z(m-2048)=y(m); 
end 
Y5=fft(z); 
Y5=abs(Y5); 
 
for m=1:512 
   noise1(m)=(Y2(m)+Y3(m)+Y4(m)+Y5(m))/4; 
   %noise(m)=Y2(m); 
   noise(m)=noise1(m)*noise1(m);    
end

%hamming windows  
for n=1:512 
   w(n)=0.54-0.46*cos(2*pi*(n-1)/511); 
end  
%籵riginal speech 
x=1:1:(length(y)-384); 
for m=1:(length(y)-384); 
   z(m)=y(m); 
end 
subplot(2,1,1); 
plot(x,z); 
%axis([0,27000,-0.4,0.4]); 
%wavwrite(z,8000,8,'d:\cj1.wav');  
%add zeros at the begining of the speech 
    
for m=1:length(y) 
   result(m)=0; 
   if(m<=385) 
      z(m)=0; 
   end 
   if(m>385) 
      z(m)=y(m-384); 
   end 
end    
 
 for m=0:((length(y)-512)/128) 
      for n=1:512 
        temp(n)=z(n+m*128)*w(n); 
      end 
      TEMP=fft(temp); 
 
      A1=abs(TEMP); 
      P=angle(TEMP); 
 
      for n=1:512 
          g=2; 
          A1(n)=A1(n)*A1(n); 
          A1(n)=A1(n)-g*noise(n); 
          if (A1(n)<0) 
              A1(n)=0; 
          end 
 end 
 
     for n=1:512 
          A1(n)=sqrt(A1(n)); 
      end 
 
      
     for n=1:512 
        R(n)=A1(n)*cos(P(n)); 
        I(n)=A1(n)*sin(P(n)); 
        M(n)=R(n)+i*I(n); 
     end 
      
     tt=ifft(M); 
     tt=real(tt); 
     for n=1:512 
         if (abs(tt(n))<0.00001) 
              tt(n)=0; 
         end 
     end 
     
     for n=1:512 
       result(n+m*128)=result(n+m*128)+tt(n); 
    end  
    
end 
 
for m=385:length(y) 
   last(m-384)=result(m)/2; 
end    
subplot(2,1,2); 
plot(x,last); 
xy=wavread('e:\voice\wgzg.wav'); 
for m=2001:2512 
   z(m-2000)=result(m); 
end 
for m=5801:6312 
    sz(m-5800)=xy(m); 
end 
nz=0; 
siz=0; 
for m=1:512 
    nz=nz+z(m)^2; 
    siz=siz+sz(m)^2; 
end 
SNR2=10*log10(siz/nz)