Magnitude and Phase Approximations of Linear Phase FIR Digital Filters by Reduced-Order IIR Digital Filters
Takashi Yahagi, Marco Aurélio Amaral Henriques · Transactions of the Institute of Systems Control and Information Engineers · 1993
This paper compares the time and memory requirements of an approximately linear phase IIR digital filter with those of a linear phase FIR digital filter, and shows that, only if a substantial difference between the orders of the filters exists, the former can be considered as an attractive substitute for the latter. Furthermore, it presents a method which makes feasible the design of reduced-order IIR digital filters that resemble the characteristics of a linear plase FIR digital filter. Some design examples are shown, illustrating how the proposed method can be used to design approximately linear phase IIR digital filters that are faster and require less memory than their equivalent linear plase FIR counterparts.