Procedure for the generation of equiripple functions

Equiripple polynomials and rational functions find extensive use in the design of filters. An nth-order equiripple polynomial is obtained by the expansion of the function cos (n cos¿1 ¿). Equiripple rational functions with specified poles can be obtained using either the method of Darlington or that of Sharpe. In the letter, a different procedure is given that can be used to generate either equiripple polynomials or rational functions with specified poles and equiripple magnitude.