Jakes信道仿真

• 已實作了MATLAB下的音頻AGC，效果還可以，做起來才發覺比較簡單，關鍵是要有高效的算法。如果能在實作AGC的同時做到噪音消除和回音消除，則效果更佳。

format long;
 % [m d] = wavfinfo('in.wav');
 [x,fs,nbits]=wavread('in.wav')
 figure;
 subplot(3,1,1);
 plot(x); xlabel('number of sample'); title('Inputput signals');
 %legend('Input signals');
  
 [N col]=size(x);
 Px=zeros(size(x));
 Py=zeros(size(x));
 y=zeros(size(x));
 g=zeros(size(x));a=0.2;
 mu=0.5;
 Pref=0.4;
％Pmin=0.000000001;
％Pmax=0.5;g(1,1)=1;
 y(1,1)=x(1,1);
 Py(1,1)=(1-a)*x(1,1)*x(1,1);
 Px(1,1)=(1-a)*x(1,1)*x(1,1);for n=2:N
   Px(n,1)=a*Px(n-1,1)+(1-a)*x(n,1)*x(n,1);
   g(n,1)=g(n-1,1)*(1+mu*Px(n,1)*(Pref-Py(n-1,1)));
   y(n,1)=g(n,1)*x(n,1);
    
   if y(n,1)>2
       y(n,1)=2;
   end
     if y(n,1)<-2
       y(n,1)=-2;
   end
  Py(n,1)=g(n,1)*g(n,1)*Px(n,1);
 end subplot(3,1,2);
  plot(y);xlabel('number of sample');
  title('Output signals');
 %legend('Output signals'); subplot(3,1,3);
  plot(g);xlabel('number of sample');title('gain');legend('gain');figure;plot(y,'r'); hold on;plot(x);
 title('Output signals & Input signals ');xlabel('number of sample');
 legend('Output signals','Input signals');      

 以下為處理的結果圖：