A class of dual-rate sampled-data models for continuous-time systems

This paper proposes a class of dual-rate sampled-data models for continuous-time systems. The proposed models are useful in digital control and in numerical simulations involving dual sampling rates which are integer related since they warrant a known time-domain performance in the limit of the sampling periods approaching zero. Designing a dual-rate control system complying to the conditions put forth in the paper, the designer warrants an intersample behavior free of undesired ripples, at least in the limit. The conditions pertain to the exogenous input signals, the discrete-time controller, and the dual-rate generalized holds and samplers. Furthermore, equivalences between dual-rate and single-rate systems are established. A numerical example illustrates the concept of dual-rate sampled-data models.