Tuner Upper Removal Demonstration

% Demonstration of LMS algorithm for noise cancellation.  Tuner upper problem.

% Rich Kozick, Spring 1997 % Rob Frohne's modifications for Macintosh 2000 % and Linux 2006 or so.

clear all Fs=8000; % 8 Khz sampling for Linux. T0 = 2;  % 2 seconds

system("espeak 'After hitting enter in the command window, speak the signal.'"); st = record(T0,Fs); %st=wavread('Hello.wav'); st=st(:,1);

system("espeak 'Here is the signal.'") soundsc(st);

Ls = length(st); T0=length(st)/Fs; % Make the tuner upper noise or even several at the same time. t=0:1/Fs:T0-1/Fs; n = 10*(sin(2*pi*100*pi*t) + cos(2*pi*600*t) + 1.5*sin(2*pi*850*t));

% Add him or them to the desired signal. x = st' + n;

system("espeak 'Here is the noisy signal.'") soundsc(x,Fs);

N = 64;  % Length of adaptive filter

% LMS algorithm for adaptive noise cancellation

h = ones(N,1); mu = 0.1; for k=N:Ls

 xk = x(k:-1:(k-N+1));
 y(k) = h'*xk';
 e(k) = y(k);
 h = h - 2*mu*e(k)*xk'/(xk*xk');

end

% The signal estimate is in the vector e system("espeak 'Here is a scaled version of the tail of the cleaned signal.'"); skip =1000; soundsc(e(skip:length(e)),Fs);