  One-dimensional tight-binding lattice, single site of which possesses
harmonically vibrating level is studied. The states of non-interacting
electrons incident with fixed energy from infinity are considered. It is shown
that at definite conditions the site reflects electrons {\it absolutely and
elastically} (high-frequency blockade states). The problem is treated both
numerically and (in the case of narrow band) analytically. The results are
compared with the free-electron 1D problem with vibrating $\delta$-functional
potential. Together with the blockade states the local and reflectionless
states are examined. Possible realization of the system as a lattice of quantum
dots is discussed.
