H(z)=(z^2+0.5z+0.1)/[(z^2+0.2z+0.4)(z-1)]
=[(z^2+0.2z+0.4)+(0.3z-0.3)]/[(z^2+0.2z+0.4)(z-1)]
=1/(z-1)+0.3/(z^2+0.2z+0.4)