  A new method for designing non-uniform filter-banks for acoustic echo
cancellation is proposed. In the method, the analysis prototype filter design
is framed as a convex optimization problem that maximizes the signal-to-alias
ratio (SAR) in the analysis banks. Since each sub-band has a different
bandwidth, the contribution to the overall SAR from each analysis bank is taken
into account during optimization. To increase the degrees of freedom during
optimization, no constraints are imposed on the phase or group delay of the
filters; at the same time, low delay is achieved by ensuring that the resulting
filters are minimum phase. Experimental results show that the filter bank
designed using the proposed method results in a sub-band adaptive filter with a
much better echo return loss enhancement (ERLE) when compared with existing
design methods.
