Further results on complex Chebyshev FIR filter design using a multiple exchange algorithm

In a previous paper, the author presented a multiple exchange algorithm for designing optimal complex Chebyshev finite impulse response (FIR) filters. This algorithm tackles the complex Chebyshev approximation problem by systematically solving a sequence of subproblems in which each subproblem is defined over a selected set of distinct frequency points. It is pointed out that the approach employed in the previous paper for solving the subproblem, which is based on an efficient implementation of Lawson´s algorithm, may encounter numerical difficulties. To alleviate this problem, a new approach which implements Lawson´s algorithm with the same computational efficiency as the previous approach while possessing better numerical property is derived