Approximating delay elements by feedback
Alessandro Beghi, A. Lepschy, Umberto Viaro · IEEE Transactions on Circuits and Systems I Fundamental Theory and Applications · 1997
A procedure for obtaining a proper rational approximant of the transfer function of a delayer is suggested. In particular, the step response of the unity-feedback system with the delayer in the direct path is first approximated by truncating the Fourier series expansion of its periodic component, and then the corresponding direct-path rational transfer function is derived, thus arriving at a stable Blaschke product.