ELLIPTIC FUNCTIONS FOR FILTER DESIGN

This paper offers a simple description of the elementary properties of the Jacobian elliptic functions and of the Landen transformation, whi ch connects them with the circular and hyperbolic functions and thereb y provides one of the most accurate methods of evaluating elliptic fun ctions, The use of elliptic functions in creating equal-ripple lowpass filters is explained and their numerical evaluation is illustrated by means of an example, A Fortran program for effecting the design is in cluded and a faster and more accurate replacement for the Matlab progr am ELLIPAP is given.