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Subject and Purpose. A new method for detecting narrow band interferences is discussed, with the use of an example record of Jovian Io-C decametric radio storm as obtained with the UTR-2 array on April 10, 2020. We aimed at developing an efficient and simple algorithm based on a detailed analysis of the effect the radio interference environment and the frequency response of the telescope may have on the efficiency of the interference mitigation procedure. Methods and Methodology. The ‘orthogonal detection’ method proposed for identifying linear interference patterns in dynamic spectra of powerful radio sources has been adapted for application to narrow band interferences of various spectral widths and variable brightness, which often happen to be located close to (or intersect with) the signal of interest. In order to minimize the impact of the telescope’s frequency response, a discretized frequency-scanning technique is used, which permits a steady approximation of the averaged spectrum by low order polynomials, as well as removal of the frequency trend which hinders distinguishing between the low-level interference signals and those coming from the source. Results. An efficient approach to the problem of detecting long lasting, narrowband interference's in dynamical spectra (conditionally stationary interferences) is proposed. The algorithm has been tested on the example of a powerful storm of Jovian radio emission. The proposed technique can be especially useful in situations where the signal of interest overlaps with the interference in the time-frequency domain. Conclusions. The new approach to the problem of interference mitigation, based on the development of combined algorithms of signal separation in the time-frequency domain, has been shown to offer an effective method of signal processing. In contrast to the previously used methods based on calculation of statistical moments for amplitudes, the new approach allows avoiding use of the same statistical indicators for both interference detection and subsequent steps of data analysis intended for building physical models and interpreting the observational data.

Subject and Purpose. The writers aim at developing and testing a new method of interference mitigation, proceeding from the example of radio emissions from Jupiter. Its effectiveness is compared with the results of other workers, equally relating to the case of a significant overlapping, within the time-frequency window under analysis, of the areas occupied by the useful signal and the interference. Methods and Methodology. The analysis has revealed several fundamental limitations associated with the use of standard statistical methods for identifying sources of interference. A new approach is proposed that allows separating useful signals from interference in the time-frequency plane. It is based on the idea of transferring the statistical analysis from the space of signal amplitudes to such of linear patterns which are formed by maximal readings while the spectrograms are being scanned in time, frequency or otherwise. Results. Methods of statistical data processing have been suggested which allow analysis of signals of a variety of power levels against the background of interference of comparable intensity. This enables a detailed analysis of the time-frequency patterns demonstrated by signals with a broad range of parameter variations. The algorithms developed demonstrate stability against changes in the interference background conditions that may be caused either by human activity or by natural factors, such as, e.g. ionospheric perturbations, changes in the fronted frequency response of a receiver resulting from a changed antenna beam orientation, or else from Faraday’s polarization plane rotation in the radio emission being received. Conclusions. The necessity of creating new interference mitigation techniques is stipulated both by worsening of the general level of interference at radio frequencies, and by the growth of complexity in the sporadically emerging time-frequency patterns that result from the improved time and frequency resolutions in the course of signal reception. A significant progress has been achieved, owing exclusively to the fundamental modifications of the signal processing algorithms that are based on varying the direction of analysis in the time-frequency plane. Conclusions. The necessity of creating new interference mitigation techniques is stipulated both by worsening of the general level of interference at radio frequencies, and by the growth of complexity in the sporadically emerging time-frequency patterns that result from the improved time and frequency resolutions in the course of signal reception. A significant progress has been achieved, owing exclusively to the fundamental modifications of the signal processing algorithms that are based on varying the direction of analysis in the time-frequency plane.

Background. This research relates to the field of aircraft location using electrostatic reconnaissance equipment. For digital processing of non-stationary electrostatic sensor signals of the system in question, convolution from the analyzing function, including a special type for a specific signal, is usually used. In this paper, a new algorithm for the synthesis of the analyzing function is proposed. Materials and methods. The least squares method was used as the initial synthesis method. The equations describe the target properties of a rational analyzing function. The properties are selected in accordance with the algorithm of using the modified Morlet wavelet function. In addition, the analyzing function was chosen to be similar to the one being analyzed. When writing the properties of functions in the form of equations, the integrals were revealed through Cauchy's residue theorem. Results. An algorithm is described and implemented that determines the coefficients of the analyzing function programmatically. Conclusions. The presented algorithm determines the coefficients of the analyzing function more accurately and in much less machine time than the algorithm based on gradient search.

Background. Digital signal processing involves sampling continuous signals. Unlike linear systems, performing this operation in nonlinear systems has a number of features associated with expanding the spectrum of the output signal. The purpose of this research is to study the sampling of signals in nonlinear systems when solving problems of modeling the dynamics of the system and restoring the output signal. Materials and methods. A class of nonlinear systems defined by the Volterra expansion is considered. Discrete nonlinear filters are used to digitally simulate system behavior. The spectral representation of nonlinear systems through multidimensional characteristics (kernels) in the frequency domain is used. Results and conclusions. The choice of sampling frequency in nonlinear systems is determined by the type of problem being solved. At the same time, the tasks of identifying the dynamic characteristics of the system and restoring the output signal of the system are highlighted. For the linear case, these problems are identical and their solution is achieved by choosing the sampling frequency of the input signal in accordance with Kotelnikov’s theorem. It is shown that the effect of expanding the spectrum of the output signal imposes different requirements on the choice of sampling frequency when solving problems of identifying and restoring the output signal in nonlinear systems.

The article considers the computational methods and features of the construction of a complex functional block for the implementation of the discrete wavelet transform (DWT) Dobeshie 9/7 in digital image signal processing systems based on FPGA. We proposed a mathematical model and algorithms for the implementation of parallel and series-convector methods of signal processing to calculate the coefficients of a discrete bi-orthogonal Dobeshie wavelet 9/7 taking into account the architecture of used FPGA. The model is based on wavelet transform factorization methods using lifting schemes. In contrast to conventional lifting schemes, the proposed method and algorithms can increase the speed of FPGA calculations with simplified hardware implementation. CAD Quartus II and ModelSim are used as a development environment. The behavioral model is written in Verilog HDL. Altera Cyclone® IV 4CE115 was used as FPGA. On the basis of the obtained behavioral model the testing module was developed and the simulation of digital circuit in the ModelSim environment was carried out. The formula for estimating the number of clock cycles of the forward and reverse DWT has been proposed; on its basis the estimate of the number of parallel computations depending on the number of input elements and the characteristics of the FPGA was obtained. As a result of experiments the dependences of the number of cycles for DWT computation depending on the size of the side of a square image with different variants of the number of parallel processing blocks were obtained. It is shown that parallel work of several independent modules gives a possibility to conduct concurrent processing of several input columns (rows) from input 2D array, and unification of the multiplier-summing module allows to increase efficiency of calculations and to reduce volume of occupied hardware resources. Conveyor based DWT structure is characterized by less hardware costs in terms of implementation of the calculator unit and memory allocation. As a result of testing the digital circuit, it was found that the developed block structure can significantly increase the DWT speed as well as reduce the cost of the system on a chip. The proposed realization of the block of two-dimensional forward and reverse wavelet transform for the Dobeshi 9/7 filter bank forms a complete module and can be used as a ready-made complex functional block for further development of high quality image transmission systems in real time.

Background. The low performance of digital filtering devices is the main problem for solving practical problems of digital signal processing. One of the ways to improve the performance of such devices is parallel signal processing using residue number system arithmetic. Materials and methods. The article proposes architectures of a truncated multiply and accumulate unit and converters for calculating modulo 2n +1. A method for filtering digital filter signals with a finite impulse response using truncated multiply and accumulate unit in residue number system with moduli of a special type {2n −1, 2n ,2n +1} was also proposed. Results. The use of moduli {2n −1, 2n ,2n +1} makes it possible to reduce hardware costs compared to moduli{2n −1,2n}. The results of hardware simulation showed that for a 32-bit filter in residue number system, the proposed moduli set allows reducing hardware costs to 32.5%, but at the same time, the delay increased to 16.4%. Conclusions. The results obtained open up the possibility of creating devices with low hardware costs.

The article deals with the concept of monitoring based on nonparametric statistics. It is supposed the possible application to monitor the technological systems of nuclear power plants. Modern complex plants and technogenic objects are equipped with industrial monitoring systems. The evolution of such systems in natural form is the generation of alternative concepts, constructs, and items selection for efficiency during operation

The paper proposes a facet vision system composed from identical facet elements. Each facet element contains an optical system, several photodetectors, a preamplifier, and a universal microcontroller. In such a system, all facet elements operate independently of each other. Each facet element performs fast measurements of the angular velocity of objects in its field of view by calculating the discrete correlation functions of the signals from the photodetectors. The paper considers the possibility of using economical microcontrollers in facet elements for fast calculation of the discrete correlation functions. The authors perform a comparative analysis of the techniques based on the direct calculation and the calculation with fast Fourier transform. The investigation of the corresponding program code for microcontrollers in assembly language is done with calculations of the number of machine instructions and their execution time. The study confirms that economical universal microcontrollers are able to perform fast measurements by finding the maximum values of discrete correlation functions. In the case of receiving signals from 4 photodetectors, the calculation time is less than 10 milliseconds for input data arrays of 384 elements and less than 1.2 milliseconds for input data arrays of 128 elements. These results make the proposed facet vision systems applicable in navigation, orientation, and collision avoidance with moving and stationary objects in automatic vehicles, including unmanned aerial vehicles.

Gas-filled proportional detectors of ionizing radiation often contain such elements as thin anode wire, which make them sensitive to external acoustic or vibrational impact. This study investigates such sensitivity for the case of the proportional γ-radiation detectors filled with high-purity xenon gas. The detector demonstrates a dependence of its signal noise on the external acoustic wave frequency, the character of which most likely depends on the design of the detector, i.e. on such parameters as diameter and tension strength of the anode wire, etc. To suppress the negative impact of acoustic noise on the characteristics of the detector, the detector digital signal is processed in a Field-Programmable Gate Array board. The authors investigate the algorithm of «time windows», which allows separating (filtering) low-frequency noise in the output signal of a gas-filled detector, which arises due to the influence of external sound, from the useful signal, i.e. the ionization pulses. This approach allows performing spectral measurements of γ-radiation with a significant acoustic noise background, when detectors with a conventional analog spectrometric channel cannot handle the task.

Objectives. Developing the element base of field-programmable gate arrays (FPGA) may significantly affect the design of electronic devices due to the enhanced logical capacity of such chips and the general tendency towards increased subsystem integration. The system-on-a-chip (SoC) concept is aimed at combining receiving, processing, and exchange subsystems onto a single chip, as well as at implementing control, diagnostic, and other auxiliary subsystems. The study aimed at developing a method for soft processor applications, i.e., processors based on configurable logical resources, for implementing control functions in an FPGA-based SoC.Methods. A digital system design methodology was used.Results. For soft processors, a unified design route based on selecting architectural parameters qualitatively corresponding to control tasks was considered. In particular, such parameters as instruction set addressness, number of pipeline cycles, and arithmetic logic unit configuration are adjustable at the design stage to allow the optimization of the soft processor in the discrete parameter space. An approach to rapid prototyping of the assembler based on stack-oriented programming language with regular grammar was also considered. The control of digital signal processing hardware as part of an SoC is the promising application area for soft processors. An implementation is considered on the example of an SoC based on Xilinx Virtex-7 FPGA containing several processor cores developed using the proposed methodology.Conclusions. The considered approaches to soft processor design allow the rapid prototyping of the control processor core for operation as part of an FPGA-based SoC.

Subject and Purpose. Smoke, fog, avalanches, debris of collapsed structures and other optically opaque obstacles in both natural and man-made disasters make optical sensors useless for detecting victims. Electromagnetic waves of the decimeter range penetrate well almost all obstacles, reflect from the trapped people and return to the radar receiver. Due to the breathing and heartbeat, the human-reflected sounding signals get the Doppler phase modulation, which is an information signal. These information signals and their properties provide the subject matter for the present research with the aim to create optimal methods and algorithms of random event processing for the prompt location of survivors by rescuers. Method and Methodology. The method of stochastic analysis of the fluctuation Doppler spectra of reflected sounding signals shows that the information signals have properties of conditional Markov processes. Results. The problem of optimal nonlinear filtering of conditional Markov processes entering the radar signal processing unit has been examined closely. An optimal adaptive filter has been proposed to reduce the masking effect of interferences caused by non-stationary noises and sounding signal reflections from stationary objects. The optimality criterion is the minimum mean square error function whose current value is evaluated in real time during the filtering process as the statistics is accumulated. The filter coefficients are calculated by the recurrent, steepest descent algorithm. The real-time work is carried out through the use of fast Fourier transform algorithms. Conclusion. The structure of the optimal adaptive filter to be built into the radar signal processing unit has been developed. Real radar signals have shown that the optimal filtering during the signal processing in systems designed for detecting live people by their breathing and heartbeat facilitates the interpretation of the observed signals. Some spectra of real signals generated by human breathing and heartbeat are presented.

The paper presents the results of research of electromyography signals and their application to control prostheses. There are compiled upper limb prostheses classification scheme. Signals are determined with the potential to identify them in various patterns responsible for the hand gestures. A program for processing signals has been developed to obtain the resulting patterns of hand movements in the LabView software environment. The main result of the program is the identification of possible gestures and the development of an appropriate response to control the prosthesis.

Biomechanics of motor actions solves the problems of analysis of external motor events - kinematic and dynamic movement parameters. Inertial measurement devices such as gyroscope and accelerometer are used for biomechanical analysis of human movements. The paper describes an algorithm for analysis of kinematic characteristics of the running based on inertial gyro signals. Running is used to estimate the physical performance, endurance, coordination abilities of a person. Gyroscope signals were registered using the TrignoTM Wireless System. For data analysis in the MATLAB, the software for automated evaluation of electromyographic and biomechanical motion patterns was developed. The algorithm allows one to calculate time, spatial and spatial-to-time parameters of motion, symmetry of movements of the left and right limbs, and also stability of repetition of biomechanical movement pattern. The algorithm includes the following stages: 1) adaptive filtering of signals; 2) identification of movement phases; 3) calculation of spatial and time symmetry of left and right limbs; 4) analysis of the repetition stability of biomechanical movement pattern. The proposed algorithm was used to estimate the motor coordination potential of high-skilled athletes in longdistance running. The research made it possible to estimate individual features of work of each group of muscles for each sportsman while performing a test task with stepwisely increasing load on a running track. This approach is a tool to detect asymmetric work of paired muscle groups and of muscle groups with irrational workability. The proposed algorithm for the analysis of running kinematic characteristics can be used to develop new criteria for evaluating the effectiveness of solving a movement problem, as well as to assess the correctness of the movement technique and identify errors that can lead to injuries.

Background. In the field of digital signal processing, there are many problems that can not be solved with traditional linear filtering methods. In particular, the use of linear filtering does not allow separating signal from the noise in the case when the spectra of the useful signal and interference overlap. The purpose of this work is to research a class of digital nonlinear filters that have significantly wider capabilities than linear filters. Materials and methods. To describe the process of nonlinear filtering, a discrete Volterra representation is used, which makes it possible to represent a digital nonlinear filter in the form of a set of nonlinear discrete convolutions characterized by kernels of different orders. This representation is a natural generalization of digital linear filtering to the non-linear case. To reduce the dimensionality of the kernels and simplify the analysis of the nonlinear filtering process, the reference regions of digital nonlinear filters are limited to slices in the time and frequency domains. Results and conclusions. The proposed approach allows one to describe the variety of digital nonlinear filters defined on the slices of kernels from a single point of view, and to classify them in the time and frequency domains. As examples of use, the problems of noise suppression in pulsed and narrow-band signals are considered, the solution of which is impossible using linear filtering methods. The proposed classification of digital nonlinear filters makes it possible to reasonably choose the structure and characteristics of a nonlinear filter for solving various problems of digital signal processing.

The purpose of this paper is to develop a method to enhance reliability of vibrational diagnosing of variable-speed industrial equipment. A dataset of vibration acceleration signals, picked up at the variablespeed test stand, has been obtained. Preliminary splitting of a vibration signal into three frequency ranges has been proved to be necessary. Vibration power dependencies on the main shaft speed have been estimated in different frequency ranges. The paper proposes an algorithm compensating variations of instantaneous power of vibration signal where equipment operation speed varies. It is based on the use of empirical dependencies of vibration signal power on shaft speed, which were derived by ensemble averaging of preliminarily split signals. A root mean square (RMS) value calculated in a sliding window is used to estimate variation of signal power. For signals within each frequency range, ensemble-averaged relative power variation produced by speed deviation is to be estimated. Instantaneous values of signals in each frequency range are to be divided by relations estimated as above. Thus, only power variations caused by variable speed are compensated. Variations caused by defect evolution are preserved. The resulting signal to be further analysed is derived by summation of processed signals in three frequency ranges. Power variation compensation decreases dispersion of parameters of signal that are used for estimation of equipment state. Preliminary compensation of vibration power variation caused by variable operation speed has proved to be effective for improving vibrational diagnostic system results. The proposed algorithm was validated on such statistical parameters of vibration as RMS and peak-factor of vibration signal.

Subject and Purpose. The paper presents a technology of constructing a promising meteor-burst communication system (MBCS) with code division multiplexing. It increases the bandwidth and improves the noise immunity and covert operation of the system. Methods and Methodology. The proposed technology is based on software-defined radio (SDR) and provides MBCS adaptation to the environment conditions by means of software parameter control of the signals and their transfer protocols. It includes a technique of forming a large ensemble of signals with a direct sequence spread spectrum and improved auto- and cross-correlation properties, involves the optimal reception and matched digital filtering of large-base signals. In order to improve the noise immunity, the narrow-band interference rejection in the signal spectrum is proposed and is jointly software installed with the matched filtering. The detection and synchronization techniques effectively working in the non-Gaussian and non-stationary interference conditions gained consideration. Results. A method of forming a large ensemble of direct sequence spread spectrum signals with improved auto- and cross-correlation properties has been software implemented using a pseudorandom permutation of codeword elements of a maximum-length register code. Designed with the use of fast Fourier transforms, algorithms of digital matched filtering and interference rejection as applied to large-base signals have been implemented via field-programmable gate arrays (FPGA). A method of detection and synchronization of large-base signals has been proposed and software implemented on the FPGA basis. Conclusion. The proposed algorithms and their implementation methods make it possible to increase the bandwidth, improve noise immunity and enhance covert operation of the meteor-burst communication system with code division multiplexing.

This article presents automatic level control system for the HF radio-transmitting devices implemented on the basis of the inexpensive of the audio codec and field-programmable gate array. The presented automatic level control system provides a quick recovery of the output level without significant surge. А compression algorithm based on the Hamming window function is used to correct the spectral mask of the signal and increase the mean-square average power of the radio-transmission path. In conclusion, the results of laboratory tests of the offered of automatic level control system.

Two periods of scientific activity of Professor Alexander Alexandrovich Petrovsky, who was a member of the editorial board of the journal "Informatics" for 15 years (2004–2019), are presented. The main scientific results, his contribution to the development of the theory and to the hardware and software of the problem-oriented real-time systems and the processing of audio, speech and graphic information are shown, a list of the most significant works of the scientist is given.

To improve the accuracy of measuring the S-parameters of microwave devices using vector network analyzers, it is proposed to use a digital processing algorithm based on the quadrature decomposition of the measurement signal followed by accumulation during the entire observation period. The article presents the results of mathematical modeling of the algorithm, as well as the results of the algorithm in a vector network analyzer of heterodyne type P4-mvm-118.

The article introduces method of vibration signals representation based on phase trajectories. The method is proposed as a supplement for current methods in expert systems of vibration analysis to solve tasks of prior uncertainty. Preliminary feasibility analysis of the method was carried out by visual comparison using large data selection.

The methodical and software for the speech signal analysis at neurological pathologies, in particular, bulbar violations, has been offered. The approach is based on the digital signal processing methods adapted to the problem of speech analysis in clinical medicine. The result is a program developed in MatLab that performs the calculating and plotting spectrogram, histogram, kepstrogramm, frequencies of the main tone for the recorded speech tests. Approbation of the method was performed on the basis of Republican research and clinical center of neurology and neurosurgery and showed the prospects of its use for the diagnosis of bulbar syndrome.

Increasing the effectiveness of vibration-based diagnosis is carried out by developing new approaches to assess the technical condition of equipment. The effectiveness of the use of a scalogram as a tool for condition monitoring of equipment is estimated in the article.

Evaluation of the technical condition of rotary equipment on vibration signals is traditionally important task in the practice of its production and operation. At the present an increase in the effectiveness of vibration-based diagnostics is achieved by automating the solution of this problem and also by the use of matched sets of informative features, which causes the urgency of the development of algorithms for their detection. The algorithm of sparse wavelet decomposition is proposed to detect shock processes in vibration signals. The algorithm is tested on the experimental material. The results of the experiment are compared with the matched wavelet filtration.

The effective approach to the estimation of athletes coordination abilities based on the reproducibility analysis of the electromyographic patterns of motion tests under the influence of external destabilizing factors is proposed. The following factors are chosen as external perturbing ones: disabling the visual and disabling the sound analyzer of a person. Two coefficients for the quantitative estimation of influence of the visual and sound analyzer on the stability of reproduction of movements with a complex coordination structure are introduced. The recommendations on the practical use of the research results for young athletes are given.

Evaluation of the technical condition of rotary equipment by vibration signals is traditionally an important task in the field of its production and maintenance. At the current stage of development increasing the effectiveness of vibration-based diagnostics is achieved by automating the solution of this problem and developing new analysis approaches. The influence of changes in shaft rotational speed of rotary equipment on the quality of frequency-domain processing is analyzed in the article. The results of experiments on test equipment are presented.

The Kola Science Center of the Russian Academy of Sciences together with the Polar Geophysical Institute is carrying out research concerning the effect of geomagnetic storms on the state of electrical networks and transformer substations on the Kola Peninsula and in Karelia. A regional system for monitoring currents in transformer neutral was created which collected a huge array of information on the influence of geomagnetic disturbances on a 800 km electric network. Overhead transmission lines are giant antennas that capture electromagnetic energy of any nature from the surrounding space. An analysis of the data accumulated over many years shows that in the current of a grounded neutral there are reliable responses to a wide range of electromagnetic phenomena on the Earth and in the near-Earth space: pulsed and quasisinusoidal pulsations of the geomagnetic field, extremely-low frequency components of artificial signals, lightning discharges and internal transients in the power system. To identify phenomena, a visual method is used to analyze the time and spectral characteristics of signals, which takes a long time and is rather subjective. There is always the possibility that some important, previously unidentified phenomena will go unnoticed. The paper describes the characteristic features of signals detected in neutral currents of power transformers. Algorithms of digital signal processing that can be used to create programs for automatic analysis of large data sets have been considered. To the greatest extent, numerical methods based on wavelet expansion and Fourier transform are suitable for studying nonsteady signals of a complex structure.

Protection of the underwater space within the territorial sea of Ukraine is one of the functions of the Armed Forces of Ukraine. Responsibility for the exercise of these functions lies directly with the Naval Forces of the Armed Forces of Ukraine. The illumination of the situation in the underwater space is one of the tasks for the Navy's ships, the successful solution of which contributes to the functions of ensuring the protection of the underwater space, increasing the protection of ships from underwater threats in the parking lots and during tasks in less dangerous areas. In order to perform these functions, the article analyzes the two-step method of additional gating of analogue-digital converter counters during I / Q-demodulation of OFDM signals, and more significantly different way of additional gating of digital signal counts in a "sliding window" mode is offered. The above proposals can be used as a basis for further scientific research on the development of the theory of digital signal processing, as well as in the production of digital segments of control systems and communication complexes of small scale surface vessels based on modern technologies.

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This article presents the implementation of digital filters used in digital relay protection current measuring elements. Mathematical descriptions of the considered digital filters as well as the computer programs for their coefficients calculation are described. It has been shown that in order to reliable estimate the digital filter performance its input signals waveforms must be close to the actual secondary current waveform of the current transformer to which the digital protection with the estimated digital filter is connected. For these purposes in MatLab–Simulink dynamic simulation environment the power system and the current measuring element models were developed. Performed calculations allowed to reveal that the exponentially decaying DC component which in some cases contains in primary fault current drives the current transformer core into saturation even when its nominal parameters are not exceeded. This results in distortion of the current transformer secondary current which in this case contains higher and inter-harmonics. Moreover, such harmonic content is not completely taking into account during coefficients calculation of the considered digital filters what results in signal magnitude estimation inaccuracy. Comparison of the digital filters response to the above-mentioned input signals allowed to find out such digital filter implementations which enable signal magnitude estimation with a minimum error. Ways of filtering quality improvement concerned with the window functions are proposed. Thus, the joint usage of digital filter and Hamming window allows to achieve the zero value of the signal magnitude gain factor in high-frequency range and substantially suppress all spectral components above 100 Hz. The increasing of the signal magnitude settling time in this case can be reduced by choosing the most optimal parameters of the all components of the current measuring element.

This article presents a comprehensive model for the two-winding power transformer digital differential protection functioning research. Considered comprehensive model is developed in MatLab-Simulink dynamic simulation environment with the help of SimPowerSystems component library and includes the following elements: power supply, three-phase power transformer, wye-connected current transformers and two-winding power transformer digital differential protection model. Each element of the presented model is described in the degree sufficient for its implementation in the dynamic simulation environment. Particular attention is paid to the digital signal processing principles and to the ways of differential and restraining currents forming of the considered comprehensive model main element – power transformer digital differential protection. With the help of this model the power transformer digital differential protection functioning was researched during internal and external faults: internal short-circuit, external short-circuit with and without current transformers saturation on the power transformer low-voltage side. Each experiment is illustrated with differential and restraining currents waveforms of the digital differential protection under research. Particular attention was paid to the digital protection functioning analysis during power transformer abnormal modes: overexcitation and inrush current condition. Typical current waveforms during these modes were showed and their harmonic content was investigated. The causes of these modes were analyzed in details. Digital differential protection blocking algorithms based on the harmonic content were considered. Drawbacks of theses algorithms were observed and the need of their further technical improvement was marked.

In the article identified a tendency of combined platforms hardware tools radiofrequency and digital signal processing for general solution communication and radiolocation tasks. The analysis of developments in the application of mobile communication of GSM standard to solving problems for airspace radar control. An analysis of developments in the area of the use of mobile communication GSM standard for solving problems of radiolocation control of airspace were made. Investigated the use of digital technology of beam forming to detect air targets with the help of mobile communication systems. Presented the results of research upper limit radio emission cellular communication systems. Appropriate researches were made by the authors during an ordinary regular flights of passenger airliners, using smartphone IPhone 5S, which was switched on mode satellite navigation to determine the current flight altitude and location coordinates. At the same time on the display of smartphone was monitored indication of presence connection with terrestrial cellular base stations appropriate for that or another locality operator communication services. Substantiated creating air space control system for the needs of special users Ukraine based on existing GSM networks.

The experience of development of a digital receiver/pulse analyzer is described. The measuring set has a modular structure and consists of three functionally independent systems: Radio Frequency Tuner, Digital Pulse Analyzer, and Data Record and Storage System. The ultra-wideband Tuner operates within 0.4 to 18 GHz. The high performance Pulse Analyzer detects up to 2 million pulses per second in real time. The Data Recording System is capable of recording raw data and results of processing for as long as 40 min at the rate of up to 3 GB/s. This measuring set is perfectly suitable for usage in radiolocation, radioastronomy, spectroscopy, in the systems for radioemission monitoring and in within the measuring-calibrating equipment.

A new two-channel digital receiver-spectrometer whose parameters and functional capabilities are optimized to provide its effective use in decameter telescopes, as well as in other systems where high precision and synchronization of measurements are required, is described. The receiver has a low level of noise floor, a high dynamic range and sensitivity. The implemented features of the receiver are continuous writing of raw data waveform mode) for the two channels simultaneously at ADC sampling rate up to 160 MHz (the maximum regulated relative inter-channel delay is 8 μs and increment 8 ps. The receiver offers flexible selection of a segment size of the fast Fourier transform ( NFFT = 210+k , k=1, ..., 5) and resulting frequency range selection (spectrometer mode) with increment of 1024 spectral samples, an ability of inter-channel cross-spectrograms real-time calculation.

Speech segmentation is intended for separation of homogeneous oscillation parts of the signal which correspond to different types of phonemes. The speech segmentation module is the fundamental element of speechlike signal generating systems for information security. The approach of the development of the speech segmentation module is considered.

Hardware realizations of arithmetic with complex integer numbers were proposed. The generators of sine and cosine with different frequency were used to make behavior stand. Real verification was made by block Spartan–3–400 Evaluation Kit, which connect up PCI of personal computer.