回声消除算法

用matlab编写程序仿真算法性能，分别对比NLMS算法与LMS算法的性能和不同步长参数η下NLMS算法的性能。代码如下：

clear all;
close all;
clc;
snr=20;
order=8;
Hn =[0.8783 -0.5806 0.6537 -0.3223 0.6577 -0.0582 0.2895 -0.2710 0.1278 -0.1508 0.0238 -0.1814 0.2519 -0.0396 0.0423 -0.0152 0.1664 -0.0245 0.1463 -0.0770 0.1304 -0.0148 0.0054 -0.0381 0.0374 -0.0329 0.0313 -0.0253 0.0552 -0.0369 0.0479 -0.0073 0.0305 -0.0138 0.0152 -0.0012 0.0154 -0.0092 0.0177 -0.0161 0.0070 -0.0042 0.0051 -0.0131 0.0059 -0.0041 0.0077 -0.0034 0.0074 -0.0014 0.0025 -0.0056 0.0028 -0.0005 0.0033 -0.0000 0.0022 -0.0032 0.0012 -0.0020 0.0017 -0.0022 0.0004 -0.0011 0 0 ];
Hn=Hn(1:order);
N=1000;
EE=zeros(N,1); Loop=150; mu=0.5;
EE1=zeros(N,1);EE2=zeros(N,1);EE3=zeros(N,1);
for nn=1:Loop
r=sign(rand(N,1)-0.5);
output=conv(r,Hn);
output=awgn(output,snr,‘measured’);
win=zeros(1,order);
win1=zeros(1,order);
win2=zeros(1,order);
win3=zeros(1,order);
error=zeros(1,N)’;
error1=zeros(1,N)’;
error2=zeros(1,N)’;
error3=zeros(1,N)’;

      for i=order:N
          input=r(i:-1:i-order+1);
          y(i)=win*input;
          e=output(i)-win*input;
          e1=output(i)-win1*input;
          e2=output(i)-win2*input;
          e3=output(i)-win3*input;
          fai=0.0001; 
          if i<200
              mu=0.32;
          else
              mu=0.15;
          end
          win=win+0.3*e*input'/(fai+input'*input);     % 不同步长的NLMS
          win1=win1+0.8*e1*input'/(fai+input'*input);
          win2=win2+1.3*e2*input'/(fai+input'*input);
          win3=win3+1.8*e3*input'/(fai+input'*input);
          error(i)=error(i)+e^2;
          error1(i)=error1(i)+e1^2;
          error2(i)=error2(i)+e2^2;
          error3(i)=error3(i)+e3^2;

% y1(i)=win1input;
% e1=output(i)-win1input;
% win1=win1+0.2e1input’; % LMS
% error1(i)=error1(i)+e1^2;
end
EE=EE+error;
EE1=EE1+error1;
EE2=EE2+error2;
EE3=EE3+error3;
end
error=EE/Loop;
error1=EE1/Loop;
error2=EE2/Loop;
error3=EE3/Loop;

% figure;
% error=10log10(error(order:N));
% error1=10log10(error1(order:N));
% plot(error,‘r’);
% hold on;
% plot(error1,‘b.’);
% axis tight;
% legend(‘NLMS算法’,‘LMS算法’);
% title(‘NLMS算法和LMS算法误差曲线’);
% xlabel(‘样本’);
% ylabel(‘误差/dB’);
% grid on;
%
% figure;
% plot(win,‘r’);
% hold on;
% plot(Hn,‘b’);
% grid on;
% axis tight;
% figure;
% subplot(2,1,1);
% plot(y,‘r’);
% subplot(2,1,2);
% plot(y1,‘b’);
figure;
error=10log10(error(order:N));
error1=10log10(error1(order:N));
error2=10log10(error2(order:N));
error3=10log10(error3(order:N));
hold on;
plot(error,‘r’);
hold on;
plot(error1,‘b’);
hold on;
plot(error2,‘y’);
hold on;
plot(error3,‘g’);
axis tight;
legend(‘η = 0.3’,‘η = 0.8’,‘η = 1.3’,‘η = 1.8’);
title(‘不同步长对NLMS算法的影响’);
xlabel(‘样本’);
ylabel(‘误差/dB’);
grid on;

clear all
close all
clc

hold off
sysorder=50; %抽头数
[inp,sr]=mp3read(‘T60=9.0.mp3’); %输入
inp=inp(?;

[d,sr] = mp3read(‘T60=0.mp3’);
d=d(?;
totallength=size(d,1); %步长
N=length(inp);
%k=0:1382493;
k=0:691246;

%算法开始
w=zeros(sysorder,1); %初始化
w1=zeros(sysorder,1); %初始化
error=zeros(N,1); %初始化
EE=zeros(N,1);
Loop=15000;

for n=sysorder:N
u=inp(n?n-sysorder+1); %u的矩阵
%u=inp(n-sysorder+1:n);
%NLMS算法
y(n)=w’u; %系统输出
r(n)=u’u; %自相关矩阵
e(n)=d(n)-y(n); %误差
srr(n)=10log10(d(n)/(inp(n)-d(n)));
srr1(n)=10log10(d(n)/(y(n)-d(n)));
%e(n)=inp(n)-y(n); %误差
fai=1e-10; %修正参数，防止r(n)过小导致步长值太大
if n<2000
mu=0.32;
else
mu=0.15;
end
w=0.8w+muu*e(n)/(r(n)+fai); %NLMS迭代方程
error(n)=error(n)+e(n)^2;

%LMS算法
y1(n)=w1'*u;
e1(n)=d(n)-y1(n);
w1=0.8*w1+0.1*u*e1(n);               %LMS迭代方程

end
EE=EE+error;
error=EE/Loop;
error=error.^2;
error(n)=error’*error;

% for i=sysorder:N1
% u1=inp2(i?i-sysorder+1);
% y_out(i)=w’u1;
% end
%srr=10log10(d/(inp-d));
%srr1=10*log10(d/(y-d));

y=y(?;
y1=y1(?;
e=e(?;
e1=e1(?;
srr=srr(?;
srr1=srr1(?;
%y_out=y_out(?;

inp1=reshape(inp,691247,2);
%inp3=reshape(inp2,342191,2);
d1=reshape(d,691247,2);
y_nlms=2reshape(y,691247,2);
y_lms=2reshape(y1,691247,2);
%y_out1=20reshape(y_out,342191,2);
error=10log10(error);
e_nlms=reshape(e,691247,2);
e_lms=reshape(e1,691247,2);
error_nlms=reshape(error,691247,2);
srr2=reshape(srr,691247,2);
srr3=reshape(srr1,691247,2);

figure(1);
subplot(3,1,1);
plot(k,inp1);
title(‘系统输出波形对比’);
xlabel(‘样本n’);
ylabel(‘混响9秒信号波形’);
subplot(3,1,2);
plot(k,y_nlms,‘r’);
xlabel(‘样本n’);
ylabel(‘NLMS输出信号波形’);
subplot(3,1,3);
plot(k,y_lms,‘g’);
axis([0 691246 -1 1]);
xlabel(‘样本n’);
ylabel(‘LMS输出信号波形’);

sound(d1,sr);
sound(inp1,sr);
sound(y_nlms,sr);
mp3write(y_nlms,sr,‘nlms.mp3’);
sound(y_lms,sr);
mp3write(y_lms,sr,‘lms.mp3’);