V.E. Avvakumov - Dr. PhD., associate professor, Experimental physics chair of the Volgograd State Technical University (VSTU). E-mail: xcpvlad@front.ru A.G. Shein - Dr. Sci., professor, Physics chair of the Volgograd State Technical University (VSTU). E-mail: alexandershein39@gmail.com M.C. Martinova - Electronics and computer techniques faculty student of the Volgograd State Technical University. E-mail: marina.111992@gmail.com

Operation of any electron microwave device is determined by the interaction of an electromagnetic wave and electronic beam. The electrons bunching is responsible electromagnetic wave, velocity close to the speed of the beam. At presence in the interaction space of several simultaneously propagating electromagnetic waves with phase velocities close to the speed of the beam, the bunch condition is more complex. This leads to the appearance of complex nonlinear effects due to competition waves. To study phenomena in M-type traveling wave amplifier is a mathematical model advanced for the dual interface. The frequency spectrum of the competing waves is presented as a set of spectral components of some of the fundamental frequency. Relationship of waves due to electronic processes only thread, submitted as a set of large particles. The paper considers processes while increasing three signals with close frequencies corresponding to 99, 100 and 101-nd harmonics of the fundamental frequency. This slows the system has zero variance in the specified frequency range. On the competition of main and additional signals significantly influence the ratio of power levels of input signals and their initial phases. At low power levels of competing signals on input output always dominates the main wave (it corresponds to the 100-th harmonic). In case of exceeding of the input of some «critical» levels of power of competing with the main signal wave picture dramatically changed. The main harmonics suppression occurs and additional amplification. There are areas of volatility, depending on the ratio of the initial phases of the waves. Identified criteria, leading to the emergence of possible unsustainable over time of the amplifier.