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The article investigates the operations of identifying a cellular network and searching for a cell at various signal-to-noise ratios. The estimation of frequency and time displacement, criteria for detecting the primary synchronization... more
The article investigates the operations of identifying a cellular network and searching for a cell at various signal-to-noise ratios. The estimation of frequency and time displacement, criteria for detecting the primary synchronization signal are presented. The main contribution of this article is the consideration of the step-by-step execution of the 5G cell search procedure in a complex interference environment. The decoding steps of the primary and secondary synchronization signals are being investigated. This is achieved by analyzing the signals at each step of the correlation algorithm for different signal-to-noise ratios. In order to verify the adequacy of the proposed models, a sequence operation for synchronizing 5G mobile networks with base station signals is considered. The dependence the magnitude of the error vector modulus on the signal-to-noise ratio of a physical broadcasting channel is investigated for three different channel profiles without line of sight. As a result of the experiment, the error vector of the physical broadcast channel changes from 55% to 10%, when the signal-to-noise ratio changes from 0 to 20 dB. In the multiple-input multiple-output (MIMO) mode, we received a 3 dB increase in communication energy efficiency. The findings will be useful for 5G system designers to troubleshoot synchronization problems.
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The paper represents identification of natural frequency and form of oscillation for the main construction elements of the electronic packages such as printed circuit boards, walls of the cases and other bearing parts subjected to... more
The paper represents identification of natural frequency and form of oscillation for the main construction elements of the electronic packages such as printed circuit boards, walls of the cases and other bearing parts subjected to vibration and shocks during operation. The current study is focused on using elements of plate bending theory, in which main boards, case walls and other planar rectangular structures are considered as equivalent homogeneous plates, in order to estimate their natural frequencies and forms of free cross oscillations and hence to identify their possible resonances with purpose to avoid them and correspondent dangerous operational modes. The significant attention was paid to the experimental research of dynamic characteristics conducted by using experimental setup created on the base of reverse and direct piezoelectric effects and also the shaker with vibration test cross appliance, representing results in form of Chladni figures and amplitude frequency response.
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The development of mobile telecommunications proceeds by increasing the productivity of communication systems, increasing the speed of information transmission, expanding the frequency band, and reducing delays. A software defined radio... more
The development of mobile telecommunications proceeds by increasing the productivity of communication systems, increasing the speed of information transmission, expanding the frequency band, and reducing delays. A software defined radio (SDR) is a programmable transceiver that supports various wireless technologies without the need for hardware upgrades. The best development environment for SDR devices is field-programmable gate arrays (FPGAs) because they provide parallel data processing. The signal in the communication channel is distorted under the influence of many factors: conversion of the signal sampling frequency in the transmitter and receiver, frequency and phase shift of the signal in the communication channel, signal delay, effect of white noise, etc. To reduce the impact of these effects, the receiver includes a synchronization circuit. The receiver contains the following units: automatic gain adjustment; frequency offset correction; recovery of symbol synchronization; ...
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Mathematical model for dynamic force analysis of printed circuit boards has been designed to calculate dynamic deformations and stresses in printed circuit boards and assess their dynamic strength and rigidity. The represented model... more
Mathematical model for dynamic force analysis of printed circuit boards has been designed to calculate dynamic deformations and stresses in printed circuit boards and assess their dynamic strength and rigidity. The represented model describes a printed circuit board as a separate oscillatory system, which is simulated as prismatic beam set on two oscillating supports. Simulation and assessment of stress and deflection in printed circuit boards and obtaining their amplitude frequency responses provided recommendations, which ensure strength and stiffness of printed circuit boards subjected to dynamic loads.
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The paper represents strength research of solder joints produced on printed circuit boards by through-hole and surface mount technologies. The research methods involve static mechanical tensile and bend tests and acoustic emission method... more
The paper represents strength research of solder joints produced on printed circuit boards by through-hole and surface mount technologies. The research methods involve static mechanical tensile and bend tests and acoustic emission method application with simultaneous monitoring both mechanical characteristics and acoustic emission parameters in order to find their correlation. On the base of conducted experiments method for nondestructive strength diagnostics of solder joints on printed circuit boards by using pure bending cycling tests and method of acoustic emission has been developed.
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The paper demonstrates that vibration sustained by electronic packages while their operation or tests cannot be characterized by vibration measured either on their supporting base or on the shaker transmitting this vibration. The... more
The paper demonstrates that vibration sustained by electronic packages while their operation or tests cannot be characterized by vibration measured either on their supporting base or on the shaker transmitting this vibration. The theoretical model of the oscillating system representing electronic unit installed on the support subjected to vibration is described. Vibration transmission from the shaker to the tested electronic unit is explained as the complex problem to solve. The experimental measurement of vibration conducted inside of tested electronic units verified significant difference in amplitude of vibrations transmitted inside the units and external vibrations that units are exposed to.
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The research given in the paper is focused on the static and dynamic strength and hermetic seal of the super-high-frequency modules in conditions of excessive air pressure and temperature impacts. For conducting overpressure tests the... more
The research given in the paper is focused on the static and dynamic strength and hermetic seal of the super-high-frequency modules in conditions of excessive air pressure and temperature impacts. For conducting overpressure tests the test installation has been developed on the base of tensometry, acoustic emission, thermal and overpressure systems. The nondestructive hermetic seal diagnostics and prediction method has been developed for super-high-frequency modules' cases.
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Electronic packages with complete encapsulation by compound are in the research objective for the represented study. Encapsulation designed to provide reliable protection against all climatic impacts and increases mechanical strength of... more
Electronic packages with complete encapsulation by compound are in the research objective for the represented study. Encapsulation designed to provide reliable protection against all climatic impacts and increases mechanical strength of the package becomes the reason for potentially destructive mechanical stress that appears when packages are subjected to thermal impacts due to internal mechanical interaction between sealed components and sealant caused by difference of their physical and mechanical characteristics. The Lame-Gadolin theory that considers interaction of compound thick-walled cylinders in form of axially symmetric problem has been substantiated for the stress calculations in electronic components represented as the solids of revolution surrounded by the layer of compound and subjected to simultaneous action of pressure and temperature. Statically indeterminate problem was solved with considerations in the material properties and compatibility in deformations in order ...
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Mathematical modeling and experimental research represented in this paper is aimed at dynamic force analysis of circuit cards in order to eliminate or reduce dynamic stress and deflection to an acceptable level and to provide strength and... more
Mathematical modeling and experimental research represented in this paper is aimed at dynamic force analysis of circuit cards in order to eliminate or reduce dynamic stress and deflection to an acceptable level and to provide strength and reliability in design of circuit card assemblies subjected to vibration. In conditions when viscous friction forces are negligible and viscous friction dampers, such as liquid dampers, cannot be used reduction of oscillation amplitude in critical frequencies was proposed by creating dry friction damper. On the base of mathematical model, the method for reducing dynamic stress and deflection in critical section of circuit cards in resonance conditions has been developed by inserting additional elastic and dissipation joint introduced by dry friction damper. The dry friction damper device is introduced in three variants of design. The effectiveness of dry friction damper is characterized by its elastic and damping characteristics and especially by th...
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В даній роботі розглядаються потенційні способи захисту сигналу на базі існуючої математичної моделі каналу витоку інформації в умовах радіотехнічної розвідки. Використана в дослідженні математична модель, при різних модифікаціях функції... more
В даній роботі розглядаються потенційні способи захисту сигналу на базі існуючої математичної моделі каналу витоку інформації в умовах радіотехнічної розвідки. Використана в дослідженні математична модель, при різних модифікаціях функції правдоподібності, яка по суті представляє собою математичний запис теореми Байєса, показує яким чином із апріорних даних і результатів аналізу прийнятого коливання формуються апріорні значення. Розглянута оптимальна схема виявлення детермінованого сигналу на фоні шуму, а також чотири можливих випадки виявлення сигналу, що порівнюються с встановленим порогом H і завжди супроводжуються помилками двох видів – неправильне рішення про наявність сигналу та помилкове рішення про його відсутність. На базі першого і третього випадків запропоновані потенційні варіанти захисту вихідного сигналу.
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The article explores megatrends in management, related to the transition to digital technologies in all spheres of the economy and production in the COVID-19 pandemic. The main contribution to the analysis of the current state of... more
The article explores megatrends in management, related to the transition to digital technologies in all spheres of the economy and production in the COVID-19 pandemic. The main contribution to the analysis of the current state of digitalization HR in business. The possibilities of a set of processes and methods of interaction with information in the formation of a strategy of people's management, are investigated. This is achieved through the use of integrated mobile applications and the automation of HR processes. From the results, the methodology for determining the severity of competences, indicators of behavior are proposed, the strengths and weaknesses of the company's staff management system in the COVID-19 conditions are taken into account. The practical usability of work is due to the proposed competency-based approach, which makes it possible to increase the efficiency of personnel selection, taking into account key macro-competencies that find an applied form through appropriate behavioral indicators.
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The article is devoted to the design the proposed construction of the antenna system for the direction-finding complex of the UAV. The experimental part is represented by the results of mathematical modeling the behavior of the antenna in... more
The article is devoted to the design the proposed construction of the antenna system for the direction-finding complex of the UAV. The experimental part is represented by the results of mathematical modeling the behavior of the antenna in different parts the operating frequency range. The effectiveness of the adopted design solutions was evaluated in comparison with analogues of leading companies in the world. Based on the results of the research, the areas of application the antenna as part of the built-in functional mobile UAV direction finding systems were determined.
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В запропонованій роботі розглянуто схемотехнічні аспекти забезпечення умов синхронізації в системах зв’язку з OFDM. Наведено дослідження оцінок міжканальних та міжсимвольних завад в системах синхронізації. Описано та алгоритмізовано... more
В запропонованій роботі розглянуто схемотехнічні аспекти забезпечення умов синхронізації в системах зв’язку з OFDM. Наведено дослідження оцінок міжканальних та міжсимвольних завад в системах синхронізації. Описано та алгоритмізовано можливі сценарії оцінки завад в каналах з OFDM за навчальними послідовностями та пілот-сигналами. Наведено експериментальні результати оцінки спотворення OFDM-сигналів в умовах міжканальних завад на основі сигналів типу 16QAM. Здійснено порівняльний аналіз середньоквадратичної оцінки міжканальних завад для трьох методів синхронізації які досліджувались у статті. Розглянуто конструкції OFDМ-сигналів з пілот-сигналами. Досліджено концепції схемотехнічної реалізації систем тактової синхронізації в каналі зв’язку з OFDM. Проілюстровано процес спрацювання системи синхронізації з метою компенсації спотворень на основі сформованої сітки ресурсів в каналі зв’язку з OFDM.
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The article is devoted to the design the proposed construction of the antenna system for the direction-finding complex of the unmanned aerial vehicle (UAV). The experimental part is represented by the results of mathematical modeling the... more
The article is devoted to the design the proposed construction of the antenna system for the direction-finding complex of the unmanned aerial vehicle (UAV). The experimental part is represented by the results of mathematical modeling the behavior of the antenna in different parts the operating frequency range. The effectiveness of the adopted design solutions was evaluated in comparison with analogues of leading companies in the world. Based on the results of the research, the areas of application the antenna as part of the built-in functional mobile UAV direction finding systems were determined.
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In a digital communication system, the transmitter and receiver have several generators for modulation and demodulation; increasing and decreasing the sampling frequency; synchronization of symbols and bit streams. The causes of phase and... more
In a digital communication system, the transmitter and receiver have several generators for modulation and demodulation; increasing and decreasing the sampling frequency; synchronization of symbols and bit streams. The causes of phase and carrier frequency errors are the instability of the frequency of the local generators of the transmitter and receiver; presence of Doppler frequency shift; signal propagation delay from the transmitter to the receiver. Synchronization circuits of modern digital communication systems are built on the basis of phase-locked loop (PLL). The purpose of the work is: research of various characteristics of the digital PLL (locking time; established error; transient behavior) for various types of input action; study of the bit error rate of a coherent digital communication system. The PLL consists of the following components: a phase detector that generates a signal that varies in proportion to the phase difference between the input signal and a locally gen...
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Wrapping vehicles with a special foil is not only a desire to stand out, change color, advertise your company or mark a special vehicle, but also a from of protecting the paint coating against the negative influence of external factors –... more
Wrapping vehicles with a special foil is not only a desire to stand out, change color, advertise your company or mark a special vehicle, but also a from of protecting the paint coating against the negative influence of external factors – e.g. UV radiation, acid rain, road pollution. It is therefore necessary to do it in a professional plant, which will guarantee that the appropriate selection of the applied film will fulfill its protective character. The article presents the issue related to the proteciton of the paint coating.
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The article explores methods for detecting and tracking air targets in radar with an artificially reduced radar cross-section (RCS). A technique for control the radar antenna system using an adaptive method is presented, which is based on... more
The article explores methods for detecting and tracking air targets in radar with an artificially reduced radar cross-section (RCS). A technique for control the radar antenna system using an adaptive method is presented, which is based on adapting the system to the conditions of information uncertainty due to fluctuations in the excitation signal of the radar target's radar-absorbing coating. Known methods of radar aircraft (active and passive, which do not take into account the structure of the coating of the aircraft) do not allow obtaining information about an air target with an artificially reduced RCS. The main contribution of this article is the development of radar and control methods based on the resonant frequency-phase interaction of the microwave electromagnetic field with the crystal structure of the radar absorbing coating of the aircraft. The stages of antenna system control based on the "frequency-phase detection method", "passive-active" track...
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У статті піднімаються питання віддаленого підключення користувачів до робочих місць. Аналізуються технології досягнення безпечного підключення та реалізація двоетапної аутентифікації зареєстрованих осіб внутрішньої мережі, що дає... more
У статті піднімаються питання віддаленого підключення користувачів до робочих місць. Аналізуються технології досягнення безпечного підключення та реалізація двоетапної аутентифікації зареєстрованих осіб внутрішньої мережі, що дає можливість підвищити продуктивність працівників завдяки доступу до файлів і системних ресурсів. Розглянута технологія полегшує роботу з іншими колегами, які працюють в межах офісу або в інших місцях. Організації мають можливість найняти найкращих спеціалістів із будь-якої частини світу, що забезпечує покращену якість продукції без додаткових накладних витрат. Проведено аналіз принципів надання віддаленого доступу за допомогою VPN. Показано, що VPN було розроблено щоб дозволити філіям безпечно отримувати доступ до програм організації. Таким чином, він забезпечує зашифроване та безпечне підключення до мережі. Визначено особливості налаштування віддаленого доступу, що має важливе значення для віддалених працівників, оскільки воно дає їм прямий доступ до ресурс...
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The article describes modern concepts for the development of Software-defined Radio (SDR) technology. A functional diagram of a software-defined radio station using the method of transmitting information with modulation based on... more
The article describes modern concepts for the development of Software-defined Radio (SDR) technology. A functional diagram of a software-defined radio station using the method of transmitting information with modulation based on Orthogonal Frequency Division Multiplexing (OFDM) is proposed. The conditions for ensuring symbol synchronization of OFDM signals are investigated. It is determined that the disruption of the orthogonality of OFDM symbols is accompanied by such phenomena as the occurrence of inter-symbol interference and inter-channel interference. The method of constellation diagrams was used to study the effect of errors caused by interference on the quality of processing of multiposition signals. The effect of interference in a channel from OFDM on the phase of signals during their processing is estimated. Mathematical models of signals with OFDM in the presence of interference effects are obtained. Two types of errors are considered, which are caused by carrier distortio...
: Software-defined radio (SDR) allows using software to set or modify working radio frequency parameters: communication standard, frequency range, modulation type, output power, etc. An interpolator is an integral part of the transmitter,... more
: Software-defined radio (SDR) allows using software to set or modify working radio frequency parameters: communication standard, frequency range, modulation type, output power, etc. An interpolator is an integral part of the transmitter, which increases the sampling frequency of the modulated signal. Interpolators are built on the basis of integrated cascaded integral-comb (CIC) non-multiplier filters. CIC interpolation filters have uneven amplitude-frequency characteristic (AFC), so the CIC compensator filter is turned on for its alignment. The eye-diagrams of signals with different interpolation coefficients are investigated in the paper. The quality of the signal in the transmitter can be evaluated by the eye-diagram. Interpolation is accompanied by the effect of amplifying the signal, reducing the time of increase in pulse, reducing the signal quality factor. The jitter in the transmitter decreases when the interpolation factor is a multiple of the sampling rate of the information sequence of symbols. If the signal quality factor is Q>7, the bit error rate has a BER<10-9 value for practice. Ref. 11, pic. 16Технология программно-управляемого радио (SDR) позволяет с помощью программного обеспечения устанавливать или изменять рабочие радиочастотные параметры стандарта связи, диапазон частот, тип модуляции, выходную мощность и тому подобное. Составной частью передатчика является интерполятор, который повышает частоту дискретизации модулированного сигнала. Интерполятор строят на основе интегральных Сascaded Integral-Comb (CIC) фильтров, не содержащих умножителей. Фильтры CIC-Interpolation имеют неравномерную АЧХ, поэтому для ее выравнивания предложено фильтр CIC-Compensator. В статье исследованы глазковые диаграммы сигналов с различными коэффициентами интерполяции. По глазковым диаграммам проведена оценка качества сигнала в передатчике. Интерполяция сопровождается эффектом усиления сигнала, уменьшением времени нарастания импульса, уменьшением коэффициента качества сигнала. Джиттер в передатчике уменьшается, если коэффициент интерполяции кратный частоте дискретизации информационной последовательности символов. Если коэффициент качества сигнала Q> 7, то коэффициент битовых ошибок имеет допустимое для практики значение BER <10-9.Библ. 11, ил. 16Технологія програмно-керованого радіо (SDR) дозволяє за допомогою програмного забезпечення встановлювати або змінювати робочі радіочастотні параметри: стандарт зв’язку, діапазон частот, тип модуляції, вихідну потужність, тощо. Складовою частиною передавача є інтерполятор, який підвищує частоту дискретизації модульованого сигналу. Інтерполятори будують на основі інтегральних Сascaded Integral-Comb (CIC) фільтрів, що не містять помножувачів. Фільтри CIC-Interpolation мають нерівномірну АЧХ, тому для її вирівнювання запропоновано фільтр CIC-Compensator. У статті досліджені око-діаграми сигналів з різними коефіцієнтами інтерполяції. За око-діаграмою проведено оцінювання якісті сигналу у передавачі. Інтерполяція супроводжується ефектом підсилення сигналу, зменшенням часу наростання імпульсу, зменшенням коефіцієнту якості сигналу. Джиттер у передавачі зменшується, якщо коефіцієнт інтерполяції кратний частоті дискретизації інформаційної послідовності символів. Якщо коефіцієнт якості сигналу Q>7, то коефіцієнт бітових помилок має припустиме для практики значення BER<10-9.Бібл. 11, іл. 1