Accelerated procedure for the design of equiripple nonrecursive digital filters

An accelerated procedure for the design of equiripple nonrecursive digital filters is described. The new procedure entails two techniques. The first technique is a selective search for the maxima of the error function, and it replaces the exhaustive search proposed by Rabiner, McClellan and Parks. It leads to a large saving in the number of function evaluations. The second technique is a more effective approach for the rejection of superfluous maxima of the error function. It can lead to a significant reduction in the number of iterations. The two techniques together lead to an overall saving in the amount of computation in the range 55 to 83%, depending on the filter specifications.