Direct Design of Infinite Impulse Response Filters Based on Allpole Filters
Alfonso Fernandez-Vazquez, Gordana Jovanovic · Signal Processing · 2010
In this chapter, we have proposed a new general framework to designing real and complex allpole filters with given degree of flatness, and with phase and group delays at any desired set of frequency points. The filter coefficients are obtained by solving a set of linear equations. In the proposed allpole filter design, we can control the phase, group delay, and degree of flatness at different frequency points. Consequently, as demonstrated here, our proposal is useful for special IIR filter designs, i.e., linear-phase Butterworth-like filter, Butterworth-like filters with improved group delay, complex wavelet filters, fractional Hilbert transformers, and new IIR filters based on three allpass filters.