A novel approach to an IIR digital filter bank with approximately linear phase

A filter bank is presented, which is based on coupled all-pass filters. The special properties of the filter bank are approximately linear phases of the subbands, perfect reconstruction and a low group delay. The synthesis filter bank is just a simple summation. The filter bank represents a generalization of the well-known lattice wave digital filters (LWDFs). For this reason, most properties of the wave digital filters are maintained, for instance, their excellent stability behavior and an extremely low sensitivity coefficient (see Fettweis, A., Proc. IEEE, vol.74, no.2, p.270-327, 1986). The design of the all-pass filters is performed by an iterative procedure. Finally, the filter bank is illustrated by means of a design example