The influence of self-excited and parametric vibrations on system vibrations has been examined in this paper. External harmonic excitation in the main area of the parametrical resonance was taken into account as well. The influence of the parameter values, including the system external excitation, on its behavior in the synchronization area was calculated analytically. The vibration amplitudes, the width of the synchronization areas and the characteristic system features were calculated as well. The solution stability analysis was verified by numerical and analog simulation.