Simplified error models for digital filters

Statistical error models for digital filter roundoff noise estimation are usally based on a set of noise sources interconnected according to the filter structure. The location of the noise sources depends on the location of the quantizers within the filter network. Roundoff noise analysis by both, simulation of digital filters and analysis of noise models yields the result that the entire roundoff noise behaviour even of multimesh digital filters can be described by exactly one quatizer if the noise power is not too great. In this contribution the assumptions for the conventional statistical noise analysis are discussed in detail Also practical methods for the determination of the characteristics of the one-quantizer-model are given. The applicability of the proposed simplified error model is demonstrated by the roundoff noise analysis of different filter structures utilizing various quantizers.