On a certain energy relationship for waves in systems having traveling parameters

A relationship is derived that couples the total energies and frequencies of quasimonochromatic wave packets that propagate in linear systems having parameters that vary in time and space according to the law governing a traveling wave having an arbitrary profile.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 15, No. 1, pp. 51–54, January, 1972.The author thanks N. S. Stepanov for raising the problem and his help with the work, and likewise M. A. Miller and L. A. Ostrovskii for their helpful comments.