Minimax design of recursive digital filters with a lattice denominator

Abstract

The authors deal with the problem of minimax recursive digital filter design with a lattice structure for the denominator. The design problem is formulated so that the coefficients for the numerator and denominator of a recursive filter can be found by solving the best linear complex Chebȳshev approximation (LCCA). A design technique based on the weighted least-squares algorithm previously proposed by one of the authors is then developed for solving the resulting LCCA problem. During the design process, this technique finds the tap coefficients for the numerator and the reflection coefficients for the denominator simultaneously. The stability of the designed recursive filter is ensured by incorporating an efficient stabilisation procedure to make all of the reflection coefficient values fall between –1 and +1. Computer simulations show that the proposed technique provides better design results than existing techniques.