DESIGN OF FIR FILTERS WITH COMPLEX DESIRED FREQUENCY-RESPONSE USING AGENERALIZED REMEZ ALGORITHM

Complex approximation with a generalized Remez algorithm is used to de sign FIR digital filters with nonconjugate symmetric frequency respons es. The minimax criterion is used and the Chebyehev approximation is p osed as a linear optimization problem. The primal problem is converted to its dual and is solved using an efficient, quadratically convergen t algorithm developed by Tang [1]. Optimal Chebychev real-coefficient FIR filters with group delay smaller than half the filter length can b e designed with slightly better magnitude responses compared to linear -phase filters. Linear-phase filters can also be designed when the gro up delay is specified to be half the filter length. Most importantly, the design method is capable to produce filters with complex coefficie nts that approximate nonconjugate symmetric frequency responses.