Canonic look ahead: critical cycle relaxed IIR filtering with minimum multiplicative complexity

In this paper we present an architecture to relax the critical cycle associated with the feedback operations in IIR filtering when high sampling frequencies exceed the computation bandwidth of digital arithmetics. Its complexity, evaluated in terms of multiplications per output sample per pole, equals that of the canonic IIR recursion and provides considerable savings in comparison to existing techniques such as clustered and scattered look ahead. The procedure is shown to yield unconditionally stable implementations