  Definition of a quantum corridor describing monitoring a quantum observable
in the framework of the phenomenological restricted-path-integral (RPI)
approach is generalized for the case of a finite resolution of time. The
resulting evolution of the continuously measured system cannot be presented by
a differential equation. Monitoring of the position of a quantum particle is
also considered with the help of a model which takes into account a finite
resolution of time. The results based on the model are shown to coincide with
those of the phenomenological approach.
