sys

Dynamic system model or array of such models.

bool

Logical value indicating whether sys is a discrete-time model.

bool = 1 (true) if sys is a discrete-time model (sys.Ts ≠ 0). If sys is a continuous-time model, bool = 0 (false).

For a static gain, both isct and isdt return true unless you explicitly set the sample time to a nonzero value. If you do so, isdt returns true and isct returns false.

For arrays of models, bool is true if the models in the array are discrete.