Efficient Non-Uniform FilterBank Equalizer

An efficient realization of a low delay filter-bank will be proposed, which can be regarded as a filter-bank used as equalizer with either fixed or time-varying spectral gain factors. The proposed filter-bank equalizer (FBE) results in a time-domain filter whose coefficients are adapted in the (short-term) spectral-domain. Perfect signal re-construction is obtained for a broad class of spectral transforms, including the generalized discrete Fourier transform (GDFT), the Walsh and Hadamard transform, with less restrictions compared to a common analysis-synthesis filter-bank (AS FB). A non-uniform frequency resolution can be achieved by frequency warping based on an allpass transformation. In this case, the filter-bank equalizer can achieve near perfect signal reconstruction with lower effort than for an allpass transformed analysis-synthesis filter-bank. The filter-bank equalizer is especially useful for adaptive filtering requiring a low signal delay with coefficient adaptation based on frequency-domain algorithms. 1