A necessity of introducing into the spectral analysis the concept of non–degenerated (degenerated) Morse critical points due to which one can completely explain an effect of intertype oscillations is substantiated. To this end the Morse points and the arising intertype oscillations are studied for a cavity open resonator and the one study inclusions with dielectric. The of the Morse points of the open resonator dispersion equation leads to fundamental changes of ideas concerning the processes in electrodynamics including the classification of fundamental frequencies.