Filter design with simultaneous magnitude and phase specifications

This paper presents a simplified method for determination of filter functions with simultaneous magnitude and phase specifications. For such, the approximation functions that attend magnitude requirements are cascaded with second-order equalizing steps, improving phase linearity. The equalizing steps are obtained through an optimization process in which convergence is achieved in all cases, from a new proposed strategy for determining initial conditions. Several examples are presented, confirming the validity of the proposed strategy and indicating that the best solution in terms of the total order of the system should be obtained from the study of each particular case. The equalization program used in this work is available for download.