An input-balanced realization-based structure for efficient implementation of digital IIR filters

Abstract

Based on an input-balanced state-space realization, this paper derives a novel structure for efficient implementation of digital IIR filters. Such a structure is very similar to a normalized lattice and, for an N th order IIR filter, it possesses 5 N -1 non-trivial multipliers: two multipliers less than in a normalized lattice. Expressions for transfer function sensitivity measures and roundoff noise gain for the proposed structure are derived. Interestingly, it is shown that, when the filter is all-pass, the proposed structure requires 4 N multiplications in order to compute one output sample. Moreover, the corresponding roundoff noise gain is 4 N , much smaller than that of ( N +1) 2 given by the classical minimum roundoff state-space realizations. Results of simulations performed show that the proposed structure outperforms many classical ones in terms of implementation efficiency and robustness against finite-word-length effects.