Procedure for the generation of equiripple functions

Equiripple polynomials and rational functions find extensive use in the design of filters. An Hth-order equiripple polynomial is obtained by the expansion of the function cos (n cos-1 ω). 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. © 1973, The Institution of Electrical Engineers. All rights reserved.