%approximations
kk=11;
[LO_D,HI_D,LO_R,HI_R] = WFILTERS('db2')
h=LO_R * 2 / sum(LO_R)

K=length(h)-1;S=128
p=[ones(1,3*S*K),0]/(3*K);
P=p(1:K*S)
axis([0 K*S+2 -0.5 1.4]);
hu=upsam(h,S);
for iter =0:kk
    p=dnsample(conv(hu,p))
    plot(p);
    pause;
end