Accelerated design of linear or minimum phase FIR filters with a Chebyshev magnitude response

An accelerated version of the well known program of Parks and McClellan for the design of linear-phase FIR filters is combined with an improved cepstral procedure to find the corresponding minimum-phase solution. Among three possibilities of speeding up the program, two recently published ones are shown to be doubtful, although a third and new one proves useful. The minimum-phase part follows the method preferred from two methods proposed previously, with some improvements. Further improvements, implemented already or yet to be investigated, are given.