  We prove the existence of stationary random fields with linear regressions
for $q>1$ and thus close an open question posed by W. Bryc et al.. We prove
this result by describing a discrete 1 dimensional conditional distribution and
then checking Chapman-Kolmogorov equation. Support of this distribution consist
of zeros of certain Al-Salam-Chihara polynomials. To find them we refer to and
expose known result concerning addition of $q-$ exponential function. This
leads to generalization of a well known formula $(x+y)^{n}%
=\sum_{i=0}^{n}\binom{n}{k}i^{k}H_{n-k}(x) H_{k}(-iy) ,$ where $H_{k}(x) $
denotes $k-$th Hermite polynomial.
