Signed power-of-two allocation scheme for the design of lattice orthogonal filter banks

In signed power-of-two (SPT) coefficient digital filter design, it is well known that a better frequency response performance can be achieved if the number of SPT terms for each coefficient is not limited to a fixed number but instead, is allowed to vary subject to a given number of total SPT terms for the filter. Many SPT term allocation schemes have been developed for distributing the number of SPT terms to the coefficients. In this paper, an SPT term allocation scheme is developed for the design of lattice orthogonal filter banks. The SPT terms are allocated to coefficients one at a time to minimize the frequency response errors due to rounding the coefficients to SPT numbers. Examples show that the proposed allocation scheme is eminently suitable for the design of SPT coefficient lattice filter banks. It is superior to those reported in the literature.