A new stable second-order section for recursive digital filters realized with logarithmic arithmetic

A new stable second-order digital filter is presented. This filter section enjoys all the stability properties of wave digital filters, including forced-response stability and stability under looped conditions. Conventional stable cascade and parallel realizations of digital filters using logarithmic arithmetic can freely be made by using this second-order section. This substantial advantage is achieved with only a slight extra cost. The simulation results demonstrate that the proposed second-order digital filter implemented with logarithmic arithmetic is always stable under all conditions of operation, as a simple strategy is taken into account in hardware realization.