  The paper establishes frequency predictability criteria and presents
predictors for two-sided non-vanishing bounded continuous time signals, i.e.,
for signals from $L_{\infty}(\R)$ that do not necessarily vanish at
$\pm\infty$. The notions of transfer functions, the spectrum gaps,
bandlimitness, and high-pass filters are introduced for these signals. This
allowed to obtain some frequency criteria for predictability and predictors for
signals with spectrum degeneracy.
