  The paper studies discrete time processes and their predictability and
randomness in deterministic pathwise setting, without using probabilistic
assumptions on the ensemble. We suggest some approaches to quantification of
randomness based on frequency analysis of two-sided and one-sided sequences. In
addition, the paper suggests an extension of the notion of bandlimitiness on
one-sided sequences and a procedure allowing to represent an one-sided sequence
as a sum of left-bandlimited and predictable sequences and a non-reducible
noise.
