H. Johansson et L. Wanhammar, High-speed recursive digital filters based on the frequency-response masking approach, IEEE CIR-II, 47(1), 2000, pp. 48-61
Citations number
48
Categorie Soggetti
Eletrical & Eletronics Engineeing
Journal title
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-ANALOG AND DIGITAL SIGNAL PROCESSING
The frequency-response masking approach for highspeed recursive infinite-im
pulse response (IIR) digital filters is introduced. In this approach, the o
verall filter consists of a periodic model filter, its power-complementary
periodic Filter, and two masking filters. The model filters are composed of
two all-pass filters in parallel, whereas the masking filters are linear-p
hase finite-impulse response (FIR) filters. The transfer functions of the a
ll-pass filters are functions of z(M), which implies that the maximal sampl
e frequency for the overall filter is M times that of the corresponding con
ventional IIR filter The maximal sample frequency can be increased to an ar
bitrary level for arbitrary band-widths. The overall filter can be designed
by separately optimizing the model and masking filters with the aid of con
ventional approximation techniques. The obtained overall filter also serves
as a good initial filter for further optimization. Both nonlinear-phase an
d approximately linear-phase filters are considered. By using the, new appr
oach, the potential problems of pole-zero cancellations, which are inherent
in algorithm transformation techniques, are avoided. Further, robust filte
rs under finite-arithmetic conditions can always be obtained by using wave-
digital all-pass filters and nonrecursive FIR biters, Several design exampl
es are included illustrating the properties of the new filters.