In this paper the concept of undular frame is defined as a system of tools consisting of waves, having the same nature as observed waves. Such definition of used tools set is equivalent to the problem about behavior and self-organizing of waves in absence of heterogeneous objects. The theorem has proved that the velocity of signal propagation in medium does not depend on undular frame selected. The location of undular frames cannot be determined relatively to the medium-carrier of waves. Between undular frames the principle of relativity is completely observed, is not possible to distinguish any undular frame. If the waves interactions are considered in undular frames, then there are gained not only trivial solutions corresponding to a principle of superposition, but also solutions, which describe interactions between waves as between mechanical particles. At the interaction of stable standing wave with the traveling wave the quantization of the latter takes place.