function y=dequat(b,x)
N=max(size(x));
y=zeros(1,N);
P=max(size(b));
for m=1:P-1
    for i=0:m-1
        y(m)= y(m)+ x(m-i)*b(i+1);
    end
end
for m=P:N
    for i=0:P-1
        y(m)= y(m)+x(m-i)*b(i+1);
    end
end
end