Model objects can represent single-input, single-output (SISO) systems or multiple-input, multiple-output (MIMO) systems. You can represent both continuous-time and discrete-time linear systems, and systems with time delays. Basic model objects such as transfer functions and state-space models represent systems with fixed numeric coefficients. Build up more complex models of control systems by representing individual components as LTI models and connecting the components to model your control architecture. For an example, see Control System Modeling with Model Objects.