A novel structure for 2nd order digital filters

In this paper, based on a new parametrization of the input-balanced realizations a novel structure is proposed for implementation of 2nd order digital filters. Like the normalized lattice structure, it contains a Givens rotation. The expression of roundoff noise gain for this structure is derived. This proposed structure is simpler than the normalized structure. Though having the same number of structure parameters as that of the classical optimal state-space roundoff realizations, it can be implemented much more efficiently using the CORDIC techniques. Numerical examples show that the proposed structure also outperforms the normalized structure and the classical optimal state-space realizations in terms of minimizing roundoff noise.