Classic сoupled-line couplers with a high lateral coupling level by type of directivity are counterdirectional. Restrictions on their synthesis are imposed by the gap between transmission lines, which must be extremely small (tens of microns), the difference in the phase velocities of even and odd modes, which must be compensated and others. This makes it difficult of manufacturing couplers. Described in technical literature сoupled-line couplers with a high lateral coupling level with changed types of directivity are either quite bulky or have small dimensions due to the use of discrete inductors and capacitances, which complicates the technological process with surface mounting when implementing the final device. In this article we propose a compact сoupledline coupler with a high lateral coupling level, which implements power transfer to a single port (0 dB, crossover). The coupler topology uses periodic loops that are located between сoupled-line. The equivalent circuit of the coupled lines was calculated and analyzed for a single periodic stub. This allowed us to determine the necessary parameters and dimensions of the topology. The device is narrow-band (3 GHz ± 5 %), transmission coefficient minus 0.44 dB at the center frequency of 3 GHz, isolation for isolated ports is not less than 35 dB. The proposed compact coupler with a coupling level of 0 dB suits building distribution circuits in which it is necessary to exclude the intersection of transmission lines. The information on the synthesis of the 3 dB co-directional microwave coupler on coupled strip lines with lateral electromagnetic coupling is given. The coupler is characterized by a high isolation level with an isolated port, not less than 40 dB. The imbalance of the amplitudes between the working (through and connected) and the input port is minus (3.4 ± 0.8) dB.

The purpose of this article is to investigate the application of DFT-modulated filter bank in systems with significant spectral component amplification like hearing aid. There is a description of analysis / synthesis method based on short-time Fourier transform (STFT), which is used in most systems of speech information processing. It is shown that DFT-modulated filter bank is a generalization of STFT-method. In analysis / synthesis system based on DFT-modulated filter bank, the input signal is divided into subbands, passing through the analysis filter bank then each subband is amplified and the last step is to reconstruct the signal with synthesis filter bank. However, in digital systems with significant spectral component amplification, the resulting signal is distorted after reconstruction because of amplification factor difference in each subband. The article provides expressions for the distortion and the aliasing functions, allowing to estimate the distortion value, which appears in analysis / synthesis system of DFT-modulated filter bank. Efficient algorithms for calculating the distortion and the aliasing functions are also offered. In future it is planning to develop a procedure for optimizing the DFT-modulated filter bank based on the proposed efficient algorithms for calculating distortion and spectral aliasing in the filter bank.

Influence of electrolyte composition and deposition parameters on the composition, structure, physicalmechanical and functional properties of composite silver-tungsten coatings was studied. It was shown that addition of sodium tungstate in electrolyte and application of ultrasound at the electroplating leads to formation of silver layers that contains tungsten oxides and demonstrates lower crystalline nucleus. Application of ultrasound vibration at the electrochemical deposition increases ability for plating process control and allows to optimize electrophysical and functional properties of composite electrochemical coatings, to make dense fine crystalline thin layers. Obtained layers demonstrate increased microhardness (by 10–50 %), wear resistance (1,5–2 times), corrosion resistance and improved contact electrical resistance. It is shown that application of ultrasound effect to electrodeposition allows increased level of permissible current density and provides.

Stabilization of residual point defects at the finishing stages of noise diodes can be ensured by the selection of appropriate ignition modes and the environment of its conduct. The method and technology of reducing the concentration of point defects in the structure of p-n-transition, taking into account the content of impurities of secondary metals, oxygen and nitrogen is proposed. It has been established that the burning of readymade structures and diodes of noise generators in nitrogen environments at temperatures of 450…600 °С for (80 ± 3) min leads to an increase in spectral noise density and a significant (twice) reduction of its unevenness. The most important result of this burn is a reduction in the spread of the average values of the noise parameters studied: by 61.2 % in effective noise voltage; spectral density by 34.2 %; at the boundary frequency of the signal by 34.9 %; in non-linear density by 25.9 %. This improves the quality of random numerical sequences in information protection software systems.

The goal of the work is to substantiate the technique for assessing the intensity of electromagnetic background generated by the set of radiating user devices of mobile communications in multi-storey buildings. For known empirical models of radio wave propagation in buildings, expressions are obtained for the probability distribution density and expectation of the power flux density of electromagnetic fields generated inside building by these sources from various parts of the building's interior space: from the near zone with radio wave propagation conditions similar to free space; and from the far zone, for which, along with intense attenuation of radio waves due to internal obstacles, a «quasi-waveguide» propagation of radio waves along corridors and industrial premises is also possible in certain directions. Relationships are obtained for the average levels of individual components of the electromagnetic background, determined as scalar sums of power flux density values of the fields generated by the sets of radiating devices of both the near zone and the far zone as a whole or its individual parts, characterized by different conditions of radio wave propagation. A method is proposed for assessing the electromagnetic background inside buildings based on approximation of sections of the inner surface of the premises in which the observation point is located, and the outer surface of the building, in the inner space of which radiation sources are randomly distributed, by the corresponding sections of the inner and outer spherical surfaces that are the subtend areas of the corresponding solid angles, in space elements of which a different spatial densities and radiation powers of sources and different conditions of radio wave propagation are possible. The results can be used to analyze the electromagnetic ecology of habitat and the electromagnetic safety of population at the full-scale implementation of 4G/5G/6G mobile communications, as well as to analyze the electromagnetic compatibility of systems using frequency bands for mobile communications on a primary and secondary basis.

The problem of automatic speech generation from a text file is considered. An analytical review of the software has been completed. They are designed to recognize texts and convert them to an audio stream. The advantages and disadvantages of software products are estimated. Based on this, a conclusion was drawn about the relevance of developing a software for automatic generation of an audio stream from a text in Russian. Models based on artificial neural networks, which are used for speech synthesis, are analyzed. After that, a mathematical model of the created software is built. It consists of three components: a convolutional encoder, a convolutional decoder, and a transformer. The architecture of the software is designed. It includes a graphical interface, an application server, and a speech synthesis system. A number of algorithms have been developed: preprocessing text before loading it into a software, converting audio files of a training sample and training a network, generating speech based on arbitrary text files. A software has been created, which is a single-page application and has a web interface for interacting with the user. To assess the quality of the software, a metric was used that represents the average score of different opinions. As a result of the aggregation of different opinions, the metric received a sufficiently high value, on the basis of which it can be assumed that all the tasks have been solved.

Present work is devoted to the development of a mathematical model for the forward current-voltage characteristic of Schottky diodes with a metal – oxide – semiconductor (MOS) trench structure, which takes into account the accumulation of the main carriers in silicon near the walls of the trenches at a forward bias. The proposed model considers the decrease of the series resistance of the Schottky diode drift region with an increase in the voltage at the rectifying contact due to the enrichment of silicon with electrons near the walls of the trenches. The proposed model is compared with the experimental results for Schottky diodes with a metal – oxide – semiconductor trench structure with a nominal reverse voltage of 45.0 V and a nominal forward current of 50.0 A. It is shown that the error in calculating the direct voltage value for the new model does not exceed 1.2 % in the range of direct currents from 20.0 to 50.0 A, which is 4.6–9.7 times less than the calculation error for the classical model. The results obtained can be used to develop the structure and geometry of Schottky diodes with a metal – oxide – semiconductor trench structure with required electrical parameters.

A research stand for microplasma treatment of object surfaces with the ability to move the discharge zone along the object using a program-controlled linear stepper motor has been developed. The design of the stand allows the use of different types of plasma generation systems, as well as processing with feeding of various gases such as air, nitrogen, oxygen, etc. into the discharge zone. The research bench is equipped with measuring equipment for monitoring the electrical and physical characteristics of the discharge (digital oscilloscopes, optical emission spectrometer, air ion meter, etc.). A microhardness tester, goniometer, interference microscope, tribometer, tensile testing machine, etc. can be used to further evaluate the quality and characteristics of the treated surfaces. Examples of the electrical characteristics of discharge devices tested as part of the research stand, optical emission spectroscopy of plasma, and results of measurements of the contact angle of treated objects surfaces are given.

The self-heating effect poses a main problem for high-power electronic and optoelectronic devices based on gallium nitride. A non-uniform distribution of the dissipated power and a rise of the average temperature inside the gallium nitride heterostructure field-effect transistor lead to the formation of a hot spot near the conducting channel and result in the degradation of the drain current, output power and device reliability. The purpose of this work is to develop the design of a gallium nitride heterostructure field-effect transistor with an effective heat-removal system and to study using numerical simulation the thermal phenomena specific to this device. The objects of the research are the device structures formed on sapphire, each of whom features both a graphene heat-eliminating element on its top surface and a trench in the passivation layer filled by a high thermal conductivity material. The subject of the research is the electrical and thermal characteristics of these device structures. The simulation results verify the effectiveness of the integration of the heat-removal system into the gallium nitride heterostructure field-effect transistor that can mitigate the self-heating effect and improve the device performance. The advantage of our concept is that the graphene heat-eliminating element is structurally connected with a heat sink and is designed for removing the heat immediately from the maximum temperature area through the trench in which a high thermal conductivity material is deposited. The results can be used by the electronics industry of the Republic of Belarus for developing the hardware components of gallium nitride power electronics.

The problem of parallel segmentation of halftone images by brightness for implementation on the basis of programmable logic integrated circuits is considered. Segmentation divides an image into regions formed from pixels with approximately the same brightness, and is a computationally complex operation due to multiple checks of the value of each pixel for the possibility of joining an adjacent region. To speed up segmentation, parallel algorithms for growing areas have been developed, in which processing begins from the neighborhoods of preselected initial growth pixels. The condition of joining an adjacent pixel to an area takes into account the average brightness of the area to limit the variance of its pixel values. Therefore, when each new pixel is added to the area, its average brightness is recalculated. This leads to high time complexity. In some parallel algorithms, the sample mean is calculated in a small window, which makes it possible to slightly reduce the time complexity when matching the window size with the segment sizes. To significantly reduce the temporal complexity, the article proposes a model for the parallel growth of image regions based on a simplified condition for joining adjacent pixels to a region, taking into account the sample average value of the region's brightness along the growth route connecting the boundary pixel of the region and the initial growth pixel through a sequence of pixels used to attach the considered boundary pixel to area. A significant decrease in the temporal complexity of the proposed model of parallel growing of image regions in comparison with the known models is achieved due to a slight increase in the spatial complexity.

The features of the implementation of the algorithm for the synthesis of detail radar images for an aperture synthesis radar using the built-in functions of the Cuda library are presented. The estimation of computational complexity from the standpoint of the organization of parallel computing on Nvidia GPUs is given. The estimation of the real performance of radar synthesis is given, taking into account the volume and features of the placement of primary radar information.

The modeling results and industrial tests of a typical automatic control system (ACS) and the proposed invariant cascade ACS are presented. The advantages of structural-parametric optimization methods for creating high-quality control systems for heat-and-power processes have been substantiated. The following algorithm for forming a block diagram of a high-quality invariant cascade SAR is proposed. At the beginning, the structure of the optimal transfer function of the stabilizing regulator is determined as the product of the inverse transfer function of the leading section of the object by a given transfer function of the open system of the internal circuit in the form of an ideal integrating link with one calculated parameter of dynamic tuning, which allows optimally working out both internal disturbances and the task of the stabilizing regulator. Then, the parameters of the dynamic adjustment of the corrective regulator are calculated for optimal processing of the extreme external disturbance. Next, an equivalent external perturbation is isolated without its direct measurement using a complete model of the inertial section of the object. At the same time, the obtained difference between the main adjustable value and the model output is fed to the input of an equivalent external perturbation compensation device implemented in the form of a differentiator, which makes it possible to increase the accuracy and speed of the invariant SAR compared to the standard one. To ensure high quality control over the entire range of load changes, the parameters of the dynamic adjustment of the invariant SAR and the model of the inertial section are adjusted in the load function.