Sobre o projeto de filtros digitais de segunda ordem imunes a ciclos limite

• Autor(a) principal: Camponêz, Marcelo Oliveira
• Data de Publicação: 1998
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/4023
• topic: Engenharia Elétrica; Eletrônica digital; Filtros digitais (Matemática); 621.3

A set of three constant-input limit cycle-free state-space second-order digital filtersections were proposed in a paper of 1986, to be used as building blocks for cascade orparallel higher order filter design. They were called structure type I, structure type II (which isentirely identical to the first one) and structure type III, by the authors who proposed them.Those structures are different from other constant-input limit cycle-free second-orderbuilding blocks in the sense that they are computationally less complex. As showed in thepaper that introduced it, the structure type I is also a low roundoff noise one, when comparedto the minimum noise structure designed under L∞ scaling. Unfortunately, because thestructure type III is slightly more complex than the structure type I (its demands three two-input adders more to be computed), its synthesis procedure and noise performance were notaddressed in the initial paper. However, it was demonstrated later, that the structure type IIIpresents relative output roundoff noise variances lower than the structure type I for the case ofL2 scaled lowpass filters.Then, in this work, the structure type III is revised, and new strategies for designing itare proposed. Under proper design, it is showed that the relative output roundoff noisevariance is minimal. Both L2 and L∞ scaling are here discussed. Examples are shown tosupport the results presented.Finally, in order to stress the good noise performance of the structure type III designedaccording to the strategies here discussed, it is compared to the noise performance of someother filter structures known in the literature. The conclusion is that the new structure type IIIhere proposed is a good candidate for being the building block to implement high ordernarrowband filters.