%Detection Guided LMS Equalizer with White Inputs%Filename: Lmseqdetec.m%Noise variance of 0.01u =[zeros(1,35),randn(1,5000)];u=sign(u);figure(1);clf;plot(u);title ('Input');grid on;zoom on;H = [1,zeros(1,2),1,zeros(1,10),-2,zeros(1,10),3,zeros(1,10)];figure(2);clf;plot (H);title ('Channel Attenuation');grid on;zoom on;mu=0.005;N=length(u);n=length(H);He=zeros(1,N);nn=randn(1,N)*0.1;U=zeros(n,1);Channel=zeros(n,N);Est=zeros(n,N);shift=diag(ones(1,n-1),-1);HH=zeros(1,n);U=zeros(n,1);b=zeros(1,n);a=ones(1,n)*0.01;c=zeros(1,n);g=zeros(1,n);d=0;sg=zeros(1,N);for i=1:N,        U=shift*U;    U(1)=u(i);    y(i)=H*U;    v(i)=y(i)+nn(i);    d=d+(v(i))^2;    sigv=d/i;    hv(i)=HH*U;    e(i)=v(i)-hv(i);    for k=1:n,        if(k<i)&(i<=N)            b(k)=b(k)+(v(i)*(u(i-k+1)));            a(k)=a(k)+((u(i-k+1))^2);            c(k)=((b(k))^2)/a(k);            if c(k)>(sigv*log(i))                g(k)=1;            else                g(k)=0;            end;            sg(i)=sum(g);            HH(k)=g(k)*HH(k)+g(k)*mu*(u(i-k+1))*e(i);        end;    end;    He(i)=(H-HH)*(H-HH)';    Channel(:,i)= H';    Est(:,i) = HH';end;%%%%%%%%%%%%%%%%%%%%%%%%%WV=zeros(n,1);w=zeros(1,5035);for i=36:5035,    WV=shift*WV;    w(i)=sign([1/HH(1)]*[v(i)-(HH(2:36)*WV(2:36))]);    Q(i)=(u(i)-w(i))^2;    WV(1)=w(i);end;figure(3);clf;plot (Q);title ('Equalizer');grid on;zoom on;%%%%%%%%%%%%%%%%%%%%%%%%%%figure(4);clf;plot (w);title ('Output');grid on;zoom on;figure(7);clf;subplot(2,1,1),plot(HH);title ('Adaptive Filter Output-Standard LMS Algorithm with Zero Tap Detection');xlabel('Number of Iterations');ylabel('Tap Weight');grid on; zoom on;subplot(2,1,2),plot(sg);title('Sum of active taps-Standard LMS with Zero Tap Detection');grid on;zoom on;figure(8);clf;subplot(2,1,1),semilogy(He);title ('Adaptive Filter Output Asymptotic Error-Uncoloured Inputs');grid on; zoom on;subplot(2,1,2),plot(sg);ylabel('Number of Active Taps');grid on; zoom on;E=(H-HH).^2;figure(9);clf;plot(E);title('Square Error of Tap Weights between Channel and Equalizer');xlabel('Tap Number');ylabel('Square Error');grid on; zoom on;