Wave digital filter structures for high-speed narrow-band and wide-band filtering

Wave digital filter (WDF) structures for high-speed narrow-band and wide-ba nd filtering; are introduced. The narrow-band filter is composed of a perio dic model filter and one or several, possibly periodic, masking filters in cascade. Lattice and bireciprocal lattice WDF filters are used for the mode l and masking filters, respectively, The wide-hand filter consists of a nar row-band filter in parallel with an all-pass filter. The overall filters ca n be designed by separately designing the model and masking filters. The fi lters obtained in this approach also serve as good initial filters for furt her optimization, Both nonlinear and approximately linear phase filters are considered. One major advantage of the new filters over the corresponding conventional filters is that they have a substantially higher maximal sampl e frequency. In the case of approximately linear phase, the computational c omplexity can also be reduced. Further, the use of bireciprocal lattice wav e digital (WD) masking filters also makes it possible to reduce the complex ity; compared with the case in which FIR masking filters are used. Several design examples and a discussion of finite wordlength effects are included for demonstrating the properties of the new filters.