A least-squares design of nonrecursive filters satisfying prescribed magnitude and phase specifications

A method is described which can be used to design nonrecursive filters satisfying prescribed magnitude and phase specifications. The method is based on formulating the absolute mean-square error between the frequency response of the practical filter and the desired response as a quadratic function. The coefficients of the filters are obtained by solving a set of linear equations. Examples for designing lowpass filters, differentiators, and allpass phase equalizers are presented. It is shown that the authors' method leads to a lower mean-square error and is computationally more efficient than the eigenfilter method.<>