A simple design of maximally flat delay digital filters

The problem of maximally flat delay design of recursive digital filters has been solved by Thiran, using a direct z-domain approach. In this paper, the solution is obtained in a much simpler way by making use of the familiar bilinear transform s of the variable z. A suitable continued fraction expansion available in the mathematical literature is shown to lead immediately to the required solution. The approach corresponds to the one used by Abele in transmission line filter design.