An alternative approach for generating linear-phase FIR filters from IIR-like filter blocks in cascade

The structure composed of a stable IIR filter G(z) in cascade with its anticausal counterpart G(z^-1) is equivalent to a zero-phase IIR filter. Truncating the impulse responses of G(z) and G(z^-1), followed by a subsequent delay transforms the structure into a linear-phase FIR. A design technique to implement the above scheme has already been proposed by the authors. This paper takes a new approach to the implementation problem by introducing a new truncation scheme, and illustrates its superiority for certain design specifications.