hilbert5.m

clc; clear all; close all;
load('100m.mat');
x=val(1,:);
ecg=x';
figure(1);
plot(ecg); grid on;
title('ecg wave'); xlabel('time (msec)'); ylabel('amplitude(mV)');
N=8; M=8;
k=input('enter the total no.of samples ');
% n=0:1:k; 
figure
n=1:1:2*k;
    for i=0:1:7
         x=ecg(n);         y=ecg(n+i+1);         z=ecg(n+i); 
          y1=y-z;          x2=y1.*y1;          x3=abs(x2);
          a(n)=x3*(N+i+1);
    end
%      disp(a); 
plot(y1);  grid on; 
title('derivated'); xlabel('time(msec)'); ylabel('amplitude(mV)');
figure;
plot(a);  grid on;
title('derivated, squared & integrated'); 
xlabel('time(msec)'); ylabel('amplitude(mV)');
%      hold on;
    figure
 n=1:1:k;
% j=1:7 %           plot(n,((a(n-j)/M)));
s1=a(n); s2=a(n+1); s3=a(n+2); s4=a(n+3); s5=a(n+4); s6=a(n+5);
s7=a(n+6); s8=a(n+7); s9=a(n+8); s10=a(n+9); s11=a(n+10); 
s12=a(n+11); s13=a(n+12); s14=a(n+13); s15=a(n+14); s16=a(n+15);
s=(s1+s2+s3+s4+s5+s6+s7+s8+s9+s10+s11+s12+s13+s14+s15+s16)/16;
disp(s); plot(n,s); grid on; hold on;
title('moving averager'); xlabel('time(msec)'); ylabel('amplitude(mV)');

figure
v=hilbert(s);
subplot(4,1,1);
 plot(n,real(v)); grid on; hold on;
 title('hilbert transform real part = moving avg.');
 xlabel('time(msec)'); ylabel('amplitude(mV)');
 subplot(4,1,2);
 stem(n,imag(v)); grid on; hold on;
 title('hilbert transform imaginary part = zero crossings'); 
 xlabel('time(msec)'); ylabel('amplitude(mV)');
% 
z1=zeros(1,k); 

for i=1:1:k
    
    if s(i)>20000 
       z1(i)=1;
    end;
    
end;
 subplot(4,1,3); stem(z1); grid on; hold on;

  z2=zeros(1,k);

for i=1:1:k-1
    
    if z1(i)==1
     diff(i)=s(i+1)-s(i);
         if diff(i)<0
           z2(i)=1;
         end;
    end;
    
end;
  subplot(4,1,4); stem(z2); grid on; hold on;
  
  
 
%  
%  z2=zeros(1,k);
%  
% for j=1:1:k-1
%     
%     if imag(v)< 20000
%        if imag(v)> -20000
%          z2(j)=1;
%     
%        end;
%       end;
%   end;
%   subplot(4,1,4); stem(z2); grid on; hold on;

  

% for i=1:1:k-1
%     if z1(i)==1
%       if angle(v)< 1
%        if angle(v)> -1
%          z2(i)=1;
%        end;
%        end;
%       end;
%  end;
%   subplot(4,1,4); stem(z2); grid on; hold on;
% 
%   
%   
  
% % plot(n,x); % plot(n,abs(x1)); % plot(n,a);% plot(n,b(n)); % plot(n,c(n));
% % hn4=fir1(N-1,fc,hamming(N));
% % [hn4,f4]=freqz(hn4,1,512,fs);
% % figure; % plot(f4,20*log10(abs(hn4)));