An extension of Darlingtonʹs algorithm for the design of elliptic filters

For the computation of parameters of elliptic filters, the evaluation of elliptic functions is necessary. For this, one can use numerical methods like Landen’s transformation or Darlington’s algorithm. In this paper, Darlington’s algorithm is extended and connected with Landen’s transformation. All formulae are mainly derived for symmetric and antimetric wave digital filters having either an even or an odd characteristic function.