  A finit periodic $\delta-\delta'$ comb was solved by the help of both
classical approach based on a direct solving of a Sr\"{odinger} equation and a
quantum wave impedance method. It was demonstrated that the violation of a
periodicity leads to the formation of energy levels in band gaps. The expresion
for a surface levels (Tamm's levels) were found in this model system. Obtained
results allow extending the scope of theoretical models which are applicable
for a describing real quantum mechanical systems as well as better
understanding the physical properties of systems in which the boundary
dependent states are involved, especially the influence of boundary dependent
electronic states on the physical properties of low-dimensional systems.
