An estimation of the logarithmic timescale in quantum systems having an
ergodic dynamics in the semiclassical limit of quasiclassical large parameters,
is presented. The estimation is based on the existence of finite generators for
ergodic measure-preserving transformations having a finite Kolmogorov--Sinai
(KS) entropy and on the time rescaling property of the KS-entropy. The results
are in agreement with the obtained in the literature but with a simpler
mathematics and within the context of the ergodic theory