Pipelined lattice digital filters utilizing asymmetrical look-ahead

Chung and Parhi (1994) introduced a simple design scheme for obtaining the k-parameters of pipelined lattice IIR digital filters utilizing the scattered look-ahead technique. The present authors show that this method actually requires double the delay suggested in order to accommodate the required delay compensation within lattice feedback loops. They propose a pipelined minimum-multiplier lattice digital filter design method which utilizes asymmetrically scattered look-ahead as in the minimum denominator multiplier technique for direct form structures. A search algorithm selects coefficients for a pre-specified frequency response, as in scattered look-ahead. The result are digital filters with lower order, and thus fewer latches and multipliers. This method does not require pole-zero cancellation, since all pipelined poles contribute to the desired response. As was the case for direct form structures, this minimum-multiplier approach of utilizing asymmetrically scattered look-ahead is demonstrated to be superior to the stricter sub-case of the scattered look-ahead technique