Some Comparisons Between FIR and IIR Digital Filters

Some comparisons are made between optimum, linear phase, finite impulse response (FIR) digital filters and infinite impulse response (IIR) digital filters which meet equivalent frequency domain specifications. The basis of comparison is, for the most part, the number of multiplications per sample required in the usual realizations of these filters -i.e., the cascade form for IIR filters,and the direct form for FIR filters. Comparisons are also made between group-delay equalized filters and linear phase FIR filters. Also, a set of design charts is made for determining the minimum filter order required to meet given low- pass filter specification for both digital and analog filters