The article explores the holographic method of measuring the antenna pattern. A flat antenna array is used as the antenna under test, and a planar rectangular surface is used as the surface on which the amplitudephase distribution in the near field is measured. Using the example of a flat antenna array, we consider the influence of the size of the measurement surface of the amplitude-phase distribution of the field in a plane orthogonal to the reconstruction plane of the radiation pattern. Antenna emitters are excited with a combined amplitude distribution and linear phase distribution. The field in the longitudinal zone of the lattice is determined using the Kirchhoff integral. The reconstructed radiation patterns are estimated using the amplitude-phase distribution over the entire measurement plane in comparison with the array radiation pattern in the far zone. A numerical analysis of the influence on the errors in determining the parameters of the lattice radiation pattern using the holographic method is also carried out: the number of columns of the amplitude-phase distribution on the measurement plane, the position of this plane in three coordinates relative to the plane of the aperture of the lattice. It is shown that if the spacing of the points of measurement of the amplitude-phase distribution and the pitch of the lattice are equal, to restore the radiation pattern using the holographic method, it is sufficient to use one column of the amplitude-phase distribution on the measurement plane. This greatly simplifies and reduces the cost of the measurement process and the necessary equipment. Examples of determining errors in measuring the parameters of the antenna array when shifting the plane of measurement of the amplitude-phase distribution in three coordinates are given.

In this paper, it’s described a method that allows to implement highly efficient amplitude modulation of radiation at the output of a ring resonator by controlling its artificial light losses, which are derived from it using two Y-shaped couplers. At the same time, the necessary constant level of light energy is provided in the resonator, which, due to the absence of radiation losses when entering it into the ring resonator, allows one to achieve a significantly lower value of the required control electric voltage than existing electro-optical modulators, and, therefore, a smaller amount of consumed electric power and an increase in working frequency range of modulation of optical radiation. The possibility of implementing the method under consideration is ensured by the fact that the input of light energy into the ring resonator can be carried out without loss, in addition, single-mode waveguides are able to maintain the temporal coherence of transmitted radiation, which ensures the implementation of multipath interference. The stabilization of the optical characteristics of a ring resonator, which is very sensitive to changes in various external factors, for example, temperature, pressure, vibrations, can be achieved by electro-optical correction of the length of the optical path of the resonator by introducing a controlled phase element operating on the transverse electro-optical effect into the ring resonator and implementing corresponding optoelectronic feedback circuit.

Results of ice quality assessment depending on various conditions of the environment and ice preparation are presented in article. The optimum indicators of the studied values influencing the ice surface quality are revealed. It is possible to estimate ice speed qualities objectively with the device, that imitates skater sliding. The purpose of the study is to determine the dependence of the sliding friction coefficient on the parameters of water treatment, the conditions for freezing the ice surface, the temperature of the ice surface, hardness and other parameters. The imitation is the movement of the mobile platform mounted on skates, supplied with the module transferring to the personal computer the values of skates sliding on the ice surface friction parameters. To measure the distance traveled by the device, the laser ranging method was used. The efficiency of the developed device and the technique of its application for assessment of ice quality on sports arenas are shown. The dependences of the quality of the ice surface on the surface temperature of the ice, air temperature, temperature of the poured water are considered. Accounting of these indicators during competitions allows to create «fast» ice for high sports results demonstration. The best values of the range of the device were recorded with the following parameters: ice surface temperature – from –3,5 to –4,5 °С, concrete slab temperature – –6 °С, ice thickness – 27–29 mm, filled water temperature – 50–55 °С, cutting the top layer of ice with an ice-filling machine – 100 %. The worst values of the range of the device were obtained with the following parameters: ice surface temperature – from –5,3 to –5,4 °С, filled water temperature – 30–35 °С, the top layer of ice was not cutby an ice-filling machine.

The paper contains a new text searching method representing modification of the Boyer-Moore algorithm and enabling a user to find the places in the text where the given substring occurs maybe with possible errors, that is the string in text and a query may not coincide but nevertheless are identical. The idea consists in division of the searching process in two phases: at the first phase a fuzzy variant of the Boyer–Moore algorithm is performed; at the second phase the Dice metrics is used. The advantage of suggested technique in comparison with the known methods using the fixed value of the mistakes number is that it 1) does not perform precomputation of the auxiliary table of the sizes comparable to the original text sizes and 2) it more flexibly catches the semantics of the erroneous text substrings even for a big number of mistakes. This circumstance extends possibilities of the Boyer–Moore method by addmitting a bigger amount of possible mistakes in text and preserving text semantics. The suggested method provides also more accurate regulation of the upper boundary for the text mistakes which differs it from the known methods with fixed value of the maximum number of mistakes not depending on the text sizes. Moreover, this upper boundary is defined as Levenshtein distance not suitable for evaluating a relevance of the founded text and a query, while the Dice metrics provides such a relevance. In fact, if maximum Levenshtein distanse is 3 then how one can judge if this value is big or small to provide relevance of the search results. Consequently, the suggested method is more flexible, enables one to find relevant answers even in case of a big number of mistakes in text. The efficiency of the suggested method in the worst case is O(nc) with constant c defining the biggest allowable number of mistakes.

The aim of this article is to create analytical models that estimate the continuity and effectiveness of digital radio communication systems using multipositional types of modulation (CAM-M, PM-M, FM-M, AM-M) and block coding according to the Reed–Solomon algorithm (RS) with hard decoding. In contrast to the well-known approaches to determining the noise immunity of systems that require computation model, new estimating models are presented that do not require knowledge of the spectrum coefficients, computer simulation training methods and graphical construction of interference curves for various types of modulation and coding parameters. The calculated ratios presented in the article include only the main parameters of the code (free distance, codeword length, relative code speed) and of the modulation type (modulation order, squared noise immunity). They make it possible to directly determine the theoretically required values of signalto-noise ratios (SNR) for input devices from given probabilistic errors based on RS signals, as well as to study the energy gain from coding (EGC), accessible and frequency-efficient systems. Based on the proposed rations, the calculations of the main characteristics of the communication channels for various parameters of the RS codes, the reliability of reception, types and orders of modulation are performed. Comparison of the results of calculation of noise immunity and system effectiveness given in the article with known similar characteristics obtained as a result of computer modeling confirms the correctness of the presented analytical models. The error of the constructed noise immunity curves does not exceed 0.1 dB in the operating range of the SNR. The materials presented in this article are original and can be used in the design, calculation and development of terrestrial and satellite systems.

The purpose of the work was to develop a speech signal processing method for the hearing pathologies correction based on psychoacoustically motivated transposition of high-frequency components of the signal spectrum to the low-frequency region with subsequent frequency-dependent amplification. To achieve this goal, several tasks related to the development of principles of frequency transposition in a speech signal were solved. The adjustment of the method is carried out according to the audiogram of a deaf person. For frequency transposition, source and target frequency bands are selected. The width of the source frequency band is fixed, while the width of the target band is adaptive. Spectrum transposition is performed only for consonants, the perception of which is more difficult for people with hearing loss. The classification of sounds (into vowel-consonant - pause classes) is implemented using one-layer neural network. The feature vector consists of: the zero crossing rate, short-term energy, short-term magnitude, normalized autocorrelation function and the first spectral moment. To preserve the naturalness of transposed sounds, the concept of equal loudness is used. To compensate for the attenuation in the perception of sound by a deaf person, a frequencydependent signal amplification based on an audiogram is used. The effectiveness of the proposed method was verified experimentally using hearing loss effect simulation. The experiment involved 10 people who were given to listen to the recordings passed through the hearing loss model, as well as recordings passed through the hearing loss model with subsequent correction (using proposed method). The results showed that using the proposed hearing correction method improves speech intelligibility on average by 6 %.

The purpose of the article is the need to create a single portrait of a radioemission source and identification methods. Radiomonitoring tools are used to detect, identify and locate sources of radioemission in the coverage area. One of the important tasks solved by the radio monitoring system is the reception (interception) of transmitted messages on the air and signal identification. The article deals with the classification of the main parameters of radioemission sources, provides a classification of the modulation types and the main its parameters. The signal structure can be determined by autocorrelation and correlation methods. Autocorrelation is used to determine signal parameters such as the transmission duration, data block duration. Correlation allows to identify a specific signal from the set. To detect a radioemission source, two generalized algorithms are presented: recognition of the radioemission source type by unknown parameters and an algorithm for identifying a radiation source by given parameters. A simulation result of a radioemission source recognition algorithm with given parameters is presented; a linear frequencymodulated signature was used as a given signal. The result of the algorithm is a single outlier with full signal compliance, when the signals diverge, the outlier width increases, which indicates a discrepancy. This algorithm can be used to search for a given type of signal, which allows to increase the strip analysis speed and the detection accuracy. To increase the detection accuracy, it is recommended to use a combination of two algorithms with additional digital signal processing, which should lead to an increase in the accuracy of type of signal determining and a more rapid determination of the radiation source parameters.

The influence of silicon wafer crystallographic orientation on the formation of porous silicon during anodization in an HF solution is studied. Cross-section SEM image comparison of samples with different crystallographic orientations has shown that (111) Si samples exhibit a more branching, tree-like pore structure with a higher porosity value compared to (100) Si samples. This phenomenon is explained by pointing out differences in crystal structure and numbers of Si-Si chemical bonds in different crystallographic directions. Namely, in (100)-oriented silicon crystals every surface Si atom has two bonds connecting it to atoms underneath it, as well as two broken bonds able to interact with Fions. Through electron injection into silicon, enough energy is applied to break the underlying bonds, forming SiF as a result. The presence of two Fions bonded with every surface silicon atom leads to weakening the bonds of surface silicon atoms with the underlying atoms, thus making the process of breaking the Si-Si bonds more energy efficient. As for (111)-oriented crystals, silicon atoms only have one broken surface bond, and breaking backbonds with underlying silicon atoms requires a higher value of activation energy due to their larger amount (three as opposed to two for (100) silicon). It is concluded that this very reason leads to slower etching speeds of (111)-oriented silicon wafers. The results help evaluate the way the silicon crystal structure affects the etching process, including its speed and direction, which is an especially important factor to consider when forming (111)-oriented porous silicon.

The article is devoted to assessing the intelligibility of the Kazakh speech when it's masked by combined signals, including «white» noise and speech-like signals. The phonetics features of the Kazakh language have been considered taking into account the law of syngarmonism and the spectrum differences of speech in the Kazakh language and speech in the Russian language. A technique for assessing the intelligibility of the Kazakh speech when it's masked by «white» noise and speech-like signals is proposed. The aim of the work is to analyze well-known methods for speech intelligibility assessing and applying these methods to assess speech intelligibility in the Kazakh language, taking into account masking by its combined signals. Due to the fact that the use of the articulation method of assessing intelligibility for the Kazakh speech requires a dependence of intelligibility on the articulation index for this particular language (the application for the Kazakh language has not been experimentally tested), the use of the formant approach to speech intelligibility assessing will be examined in more detail. The curried out experimental studies of the spectral density of speech in the Kazakh language made it possible to obtain it's approximate dependence on the frequency and take into account the phonetic features of the Kazakh speech when assessing the security of the speech information using the formant method.

The objective of the work is investigation the dielectric permittivity and dielectric loss tangent of BaTiO3 films in a capacitor structure formed by sol – gel method on a Si/TiOx/Pt substrate. The basis of this capacitor is a four-layer film of barium titanate xerogel with a thickness of about 200 nm. The film was synthesized by sol-gel method at a final annealing temperature 750 °C. The problems related to the development of method of forming multilayer capacitor structures, the analysis of the morphology and phase composition of BaTiO3 film, and also the measurement of the capacitance-voltage characteristics in the frequency range 10 kHz – 2 MHz have been solved. Morphology of the films was analyzed using a Hitachi S-4800 scanning electron microscope. X-ray diffraction spectra was recorded using a DRON-3 automated diffractometer, using monochromatic CuKα radiation. Capacitance-voltage characteristics were obtained using a B1500A semiconductor analyzer. Dielectric constant and dielectric loss tangent, calculated for capacitance measurements, are changed as follows: for a bias voltage of U = 0 V, the change in ε is 232–214, and tanδ 0.022–0.16, and for a bias voltage of U = 10 V, ε occurs in the range 135–124 and tanδ from 0.02 to 0.1. The obtained frequency dependences of the dielectric constant of BaTiO3 films show a decrease in the dielectric constant in the range of 10 kHz – 2 MHz. It was found that, with a BaTiO3 film thickness of less than 100 nm, a thin-film capacitor with a lower platinum electrode is not always formed, which is probably caused by shunting of the structure.

Present work is devoted to determination the regularity of change of specific resistance and Schottky barrier height of nickel films on n-type silicon (111) at their rapid thermal treatment in the temperatures range from 200 to 550 °C. Nickel films of about 60 nm thickness were deposited by magnetron sputtering onto the silicon substrates having a resistivity of 0.58 to 0.53 Ohms×cm. The rapid thermal treatment was carried out in the range of 200 to 550 °C under heat balance mode by irradiating the backside of the substrates with non-coherent light flux in nitrogen ambient for 7 seconds. The thickness of the nickel films was determined by scanning electron microscopy. The sheet resistance of the samples was measured by a four-probe method. The Schottky barrier height was determined from I-V plots. It is shown that at a temperatureы of rapid thermal treatment of Ni/n-Si (111) 200–250 °C nickel will be transformed to Ni2Si, increasing in thickness by 1.15–1.33 times, specific resistance increases to 26–30 μOhm×cm, and Schottky barrier height decreases from 0.66 to 0.6 V. At a rapid thermal treatment temperature of 300°C the initial nickel film thickness increases by 1.93 times, the resistivity and Schottky barrier height decrease to 26–30 μOhm×cm and 0.59 V respectively due to the conversion of the Ni2Si into NiSi and the fixation of the barrier height by surface states at the silicidesilicon interface. Rapid thermal treatment of 350–550 °C transforms the original nickel film into NiSi, increases its thickness by 2.26–2.67 times, reduces its resistivity to 15–18 μOhm×cm and increases the Schottky barrier height to 0.62–0.64 V. The minimum defects and better reproducibility of electrophysical properties are characterized by NiSi films formed by rapid thermal treatment of nickel films on n-type silicon at a temperature of 400–450 °C. The results obtained can be used in the technology of integrated electronics products containing rectifying contacts.

A method for creating the electromagnetic radiation shields, which consists in fixing fragments of aluminum foil on the surface of a needle-punched carbon-containing material has been proposed. In accordance to the proposed method the shield samples have been made. The fragments of the used aluminium foil were in the form of rectangles or half rings the overall dimensions of which didn't exceed 20 mm. Using an automated meter of transmission and reflection coefficients SNA 0.01–18, shielding characteristics in the frequency range 0.7–17 GHz of the shield samples made in accordance with the proposed method have been obtained. Using the measuring stand, the main components of which were a white noise generator, power amplifier, speaker, sound analyzer MANOM-2, in the frequency range 20–16000 Hz, the soundproofing properties of the shield samples made in accordance with the proposed method have been obtained. It was shown that the values of the electromagnetic radiation reflection coefficients in the frequency range of 0.7–17 GHz of the investigated shields vary from –0.5 to –19.0 dB, and the electromagnetic radiation transmission coefficient in the specified frequency range vary from –2.0 up to –18.0 dB. It was found that the of electromagnetic radiation reflection coefficient values in the frequency range 0.7–17 GHz and the electromagnet radiation transmission coefficient values in the frequency range 6–17 GHz of the shields made in accordance with the proposed method using fragments of aluminum foil in the form of half rings, by 1,0–6.0 dB below the same values of the shields made using fragments of aluminum foil in the form of rectangles. It was determined that the studied shields provide sound attenuation by 2–3 dB in the frequency range from 20–16000 Hz. In view of the obtained results, shields manufactured in accordance with the proposed method are recommended for use in order to protect information circulating in the premises from leakage through the acoustic channel and the channel of secondary electromagnetic radiation.

The technic of the processing of the meteorological data for conclusion on the presence of the time trends in the quantitative characteristics of the weather on the example of the analysis of the average yearly atmospheric temperature change at the meteorological station Minsk from 1989 is presented. The average yearly atmospheric temperature received from the measurements is approximated by the least square error method in the linear time dependence regression function. The linear time dependence regression function received in such a way has some positive growing (positive trend). The aim of this paper is to clarify the significance of this growth. For this aim, the usage of the regression analysis with its procedures of hypotheses testing is proposed. First of all, the performing of the demands presented to the regression analysis is checked: normality of the distribution of the disturbance and the homogeneity of the variance (dispersion) of the disturbance. The normality of the distribution of the disturbance was checked and confirmed by the Kolmogorov test. The homogeneity of the dispersion of the disturbance was checked and confirmed both by checking the hypotheses on the equality of the dispersions of two normal distributions and by the Smirnov test for checking the hypotheses on the equality of two distributions. For checking the significance of the positive trend of the yearly mean temperature, the hypotheses on the significance of the coefficients of the linear regression function by the Student t-statistics and the hypothesis on the linear connection presence by the analysis of variance were checked. As the result, the insignificance of the positive linear trend from 1998 to 2016 and from 1998 to 2017 and its significance from 1998 to 2018 and from 1998 to 2019 on the level of significance 0.05 for mean average yearly atmospheric temperature at the meteorological station Minsk was stated.