Minimax Design of Time-domain Constrained FIR Filters by a Sequential Constrained Least-Square Method

Since minimax FIR filters with timedomain constraints may not satisfy the alternating theorem, the Remez-type exchange algorithms are not guaranteed to converge or may not converge to optimal filters.A Sequential constrained least-square (SCLS) method converts a constrained minimax problem into a series of Constrained least-square (CLS) problems with unique solutionswhich positively converge to one of the minimax solutions.This paper presents an SCLS method for the minimax design of FIR filters with time-domain constraints. The effectiveness and effciency of the SCLS method are demonstrated by design examples of Nyquist, and step-responseconstrained FIR filters in comparison with several existingmethods.