d2.m

心电信号滤波

x=[-4,-2,0,-4,-6,-4,-2,-4,-6,-6,...
   -4,-4,-6,-6,-2,6,12,8,0,-16,...
   -38,-60,-84,-90,-66,-32,-4,-2,-4,8,...
   12,12,10,6,6,6,4,0,0,0,...
   0,0,-2,-4,0,0,0,-2,-2,0,...
   0,-2,-2,-2,-2,0];
subplot(1,2,1)
n=0:55;
stem(n,x,'.r');
axis([0 60 -100 50]);
b=[0.09036,0.09036*2,0.09036];
a1=[1.2686,-0.7051];
a2=[1.0106,-0.3583];
a3=[0.9044,-0.2155];
k=1;
for k=1:3
switch(k)
 case 1 
    y=filter(b,a1,x);x=y;
 case 2
    y=filter(b,a2,x);x=y;
 case 3
    y=filter(b,a3,x);x=y;
end
end
subplot(1,2,2)
stem(n,y,'.r');
axis([0 60 -15 5]);