A simplified tuning algorithm for FIR digital filters using subband decomposition

Simplifying methods for tuning the frequency response of FIR digital filters realized using the structural subband decomposition are described. Based on numerous optimal filter designs, a linear approximation for the filter coefficients as a function of the cutoff frequency has been derived. In many cases, a number of filter coefficients can be replaced with zero values without significantly altering the frequency response characteristics. The frequency response of the filters are variable within narrow frequency ranges around the nominal cutoff frequency. The proposed methods do not change the filter length since the filter coefficients are directly controlled.<<ETX>>