DESIGN OF DISCRETE COEFFICIENT FIR DIGITAL-FILTERS WITH ARBITRARY AMPLITUDE AND PHASE RESPONSES

The paper considers the design of FIR digital filters with discrete coefficients in the complex frequency domain. A design method based on a recently developed weighted least squares (WLS) algorithm is presented. First, we design FIR filters with continuous coefficients using the WLS algorithm to meet the desired frequency response specifications in the minimax sense. To avoid the effect of nonuniformly distributed coefficient grid due to discretization of filter coefficients, a procedure is then performed for obtaining an optimal filter gain factor. Finally, utilizing the resulting error weighting function obtained by the WLS algorithm, we perform an efficient discrete optimization process for obtaining a discrete solution in the minimax sense. The efficiency of the proposed method is illustrated by the design of discrete coefficient FIR filters with constant group delay and filter length greater than 60.