Theory and performance of adaptive IIR filterbanks with variable center frequencies

The theory and performance of adaptive IIR filterbanks with variable center frequencies is examined. First, the performance of a single adaptive IIR bandpass filter with fixed gain and variable center frequency is examined. The particular bandpass filter is derived from a first order Butterworth lowpass by a bilinear transformation. Next, a parallel filterbank of first order bandpass filters that cover the range up to the folding frequency is implemented. Performance error surfaces are generated. A range of frequencies are tested. The results are compared favourably with adaptive FIR filters.<>