Fast-lifting approach to the computation of the spectrum of retarded time-delay systems

This paper discusses a new method for computing the spectrum of retarded time-delay systems based on the lifting technique. Stimulated by a recent study that applied (conventional) fast-sample/fast-hold (FSFH) approximation, we consider applying modified FSFH approximation, developed in the fast-lifting approach to sampled-data systems. We show that this leads to an asymptotically exact method in a quite straightforward fashion. The effectiveness of the method is demonstrated with numerical examples.