Elliptic approximation and elliptic filter design on small computers

Two programs for the design of -ladder elliptic filters, which can be implemented on small computers, are presented. The nonconventional method used for the synthesis of ladders is first described. Then the approximation using elliptic functions better adapted to the numerical calculations than Jacobi\´s function is sketched. The first part of the first program can be used independently to solve classical elliptic approximation problems, including the calculation of the natural frequencies.