Recursive two-channel filter banks based on FRM approach

In this paper, we consider the application of a recursive half-band filter pair in the structure of two-channel filter bank, which is based on the frequency response masking (FRM) technique. The recursive filter pair is used as a complementary model filter pair, whereas the masking filters are linear-phase FIR filters. Efficient realization structures for the analysis and synthesis filter banks consisting of all-pass sub-filters and polyphase components of masking filters are derived. The resulting analysis/synthesis filter bank satisfies the all-pass and the nearly perfect magnitude reconstruction properties. It is shown in the paper that by making use of the two-channel filter bank and the two-stage FRM-approach, very sharp filters with nearly linear phase can be achieved. The performances of the analysis/synthesis bank are demonstrated by means of example. An example is also used to illustrate the application of the two-stage FRM-based filter design.