Vol 62, No 6 (2019)

The methodology of simulation of high voltage glow discharge electrodes’ systems with anode plasma, formed the profile electron beams with the ring-like focus, is considered in the article. The universality of proposed model is confirmed by the fact, that the slope angle of generatrix line of conic anode surface correspond to the axis of the electrodes system have been chosen as one of model parameters. Such novel solution has led to simulating the different types of electrodes’ systems, which form the profiled electron beams. The position of plasma boundary in considered high voltage glow discharge electrodes’ systems is firstly calculated on the basis of one-dimensional model of discharge gap, and after that recalculated with taking into account the real geometry of electrodes’ system. Such approach allows to significantly simplify the proposed mathematical model and to avoid using the sophisticated iteration numerical methods for defining plasma boundary form and position without decreasing the accuracy of simulation results. The results of simulation of plasma boundary position are compared with obtained experimental data and disagreement between simulation and experimental results is nearly 10–15%. The results of simulation of distribution of electric field in the cathode-fall region as well as results of simulation of distribution of beam current density in the ring-like focus of formed hollow electron beam are presented in the article. The simplicity and universality are the main advantages of the proposed model.

Oscillators with the primary tone synchronization and based on the frequency-divider mode have been considered in this study. The paper proposes a generalized model of injection-locked oscillator using the linear polynomial approximation of nonlinear characteristic of its amplifying element, and a new analysis technique based on peculiarities of the oscillator operation in injection-locked mode. These peculiarities imply that the oscillation amplitude can be considered as steady-state at an arbitrary instantaneous value of phase shift and that the curvature of phase characteristic of the oscillator decreases with the rise of synchronization signal amplitude within certain limits. The development of the new technique involved the use of the linear approximation method of reduced equations of injection-locked oscillator and the small parameter method. The new technique is insensitive to the form of nonlinear terms, and it allows us to obtain analytical solutions of reduced equations having different nonlinear terms that depend on the oscillator operation mode. This technique features small errors and essentially simplifies the investigation of injection-locked oscillators and their systems. The experimental test confirmed its high efficiency.

The article analyzed the possibility of the appearance of an acoustic information leakage channel that is formed by analyzing the video stream on the video record. The authors investigated the possibilities of speech recovery from a low quality recording, determined by the signal-to-noise ratio (SNR), sampling frequency, number of quantization levels, and clipping level, taking into account the features of the leakage channel under study. As a result, the required frame rate of the video image, the minimum SNR, the number of quantization levels, and a sufficient dynamic displacement range of the oscillating object are determined. The authors also investigated the requirements for the leakage channel parameters and possible ways for an attacker to improve its quality. The requirements for the displacement of an object oscillating under the action of acoustic waves in a video were calculated. The article justified the potential of reducing the requirements for the displacement of an object by applying averaging of a large number of different points on the object. The authors performed an assessment of the existing noise reduction software for sound recordings, which is used to increase the intelligibility of the message that is intercepted by the attacker in the considered information leakage channel. Obtained results revealed that there are potential causes for the leakage of acoustic information by analyzing the video stream on the video. The conditions for the emergence of such a channel are not excessive. Therefore, the possibility of its appearance is a security risk and it is necessary to provide the means to protect the object of information activity from it.