function y_n = myLMS(u_n, d_n, m, mu)

  persistent w u
  
  if isempty(w)
    w = zeros(m,1);
    u = zeros(m,1);
  end
  
  u(end+1,1) = u_n;
  
  % apply w to u
  y_n = w'*u(end:-1:end-m+1);
  
  e = d_n - y_n;
  % update w for next iteration
  w = w + mu* e * u(end:-1:end-m+1);
  
  end

%% fasma eisodou
Yx=fft(x);
n=500;
f = Fs*(0:(n/2))/n;
Px = abs(Yx/n);
figure
plot(f,Px(1:n/2+1)) 
title('Frequency Domain of input')
xlabel('Frequency (f)')
ylabel('|Yx|')

%% fasma eksodou
y = lsim(sys,'r',x,t);
Y=fft(y);
Py = abs(Y/n);
figure
plot(f,Py(1:n/2+1))
title('Frequency Domain of output')
xlabel('Frequency (f)')
ylabel('|Yx|')
grid on