Volume 7 Issue 2
ELECTRONIC NETWORK JOURNAL "RUSSIAN TECHNOLOGICAL JOURNAL"
Volume 7 Issue 1
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ROBOTIC SYSTEMS, TECHNOLOGIES FOR REMOTE SENSING AND NON-DESTRUCTIVE TESTING |
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Bityukov V.K., |
Non-contact method of measuring surface temperature 36 AbstractA non-contact method is proposed for measuring the surface temperature of an object using a standard radiator and standard object having optico-physical properties identical to those of the monitored object. Placed co-planarly with the monitored object in the field of view of an optoelectronic system (OES) is a standard object, the temperature of which is regulated and measured, and a standard radiator, whose normal spectral emissivity and temperature are known. In addition, the OES has its three fixed points, at which it registers the normal emissivity of the standard object, monitored object, and standard radiator (SR). The main distinction of the proposed method from the known ones is that the limits or tolerances for the nature of reflection and the quantitative parameters of reflection of the monitored object make no difference. The obtained analytical expression is an equation of the non-contact method of measuring the surface temperature of the monitored object, which can be applied for any spectral range of operation of the OES. A metrological analysis of the proposed method is made using a monochromatic optoelectronic system working at wavelengths of 0.65, 2.0, 5.0, 14.0, and 50.0 μm for the temperature of the monitored object, T, equals to 400, 700, and 1000 K. Based on the analysis of the results the requirement for the implementation of the proposed method of measuring the surface temperature has been formulated, which says that the choice of an optoelectronic system for measuring the surface temperature of objects should be preceded by a methodological and metrological analysis of the optico-physical properties of the monitored object, the surrounding background, and the OES itself. Keywords: pyrometry, non-contact/contactless method, measurement, temperature, mathematical model, monitored object, standard object, standard radiator, methodical and metrological analysis, monochromatic mode, optoelectronic system, background light. |
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MODERN RADIO ENGINEERING AND TELECOMMUNICATION SYSTEMS |
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Kulikov G.V., |
Abstract The energy and spectral advantages of signals with phase shift keying predetermined their widespread use in modern digital navigation, communications and television systems. The use of such signals is the base of communication standards of DVB-S, DVB-S2 / S2X, GLONASS, CDMA, WiFi IEEE 802.11 and others. To increase the capacity of radio channels, multiple phase shift keying (MPSK) is applied. This increases the number of possible phase states of the signal and, thus, the information capacity of the channel symbol. However, such an increase greatly affects the noise immunity of MPSK signal reception. In the article the noise immunity of receiving signals with multiple phase shift keying in the presence of noise and phase-shift interference is analyzed by the methods of statistical radio engineering. The dependencies of bit error probability on the signal-to-noise ratio, on the interference intensity, on the relative transmission speed of the interference, and on its detuning relative to the center frequency of the spectrum of the useful signal are calculated. It is shown that signals with multiple phase shift keying are very strongly influenced by phase-shift interference, and this influence increases with increasing signal positionality. The degree of reduction of the noise immunity of the reception depends on the magnitude of the relative transmission rate of the interference and its intensity. The damaging effect of the phase-shift interference is most pronounced when it hits the main lobe of the signal spectrum. As the relative transmission rate increases, the interference becomes more broadband and pseudo-noise, and it affects even with very large frequency detuning somewhat decreasing in the region of the main lobe of the signal spectrum. This decrease seems natural, since the analyzed algorithm for receiving MPSK signals is optimal for the effects of noise interference. Keywords: bit error rate, phase-shift interference, multiple phase-shift keying, noise immunity. |
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Legkiy N.M., |
Formation of the direction diagram in phased antenna array 33 AbstractThe article presents the results of the study of phase and temporal methods in the formation of the direction diagram of phased antenna array, and carries out a comparative analysis using an eight-element equidistant antenna array based on Vivaldi wideband slot-hole emitters as example. The practical implementations of constructing devices for forming phased antenna array direction diagrams on phase shifters for the phase diagram generation method and on delay lines, for the temporal method, are considered. The characteristics of the most frequently used Analog Devices phase shifters in the phased antenna arrays, as well as experimental delay lines are given. The results of the mathematical modeling allowed estimating the bandwidth of both types of antenna arrays. Authors note that the phase method of beamforming is not widely used in broadband systems due to the dependence of the phase of a signal on the frequency and, as a consequence, the narrow range of operation of phase shifters. In delay lines, the delay time for all channels does not depend on the frequency component of the signal, which suggests that the beamforming devices based on the principles of time delay are ultra-wideband, and the maximum length of the signal delay path for extreme emitters depends only on the maximum calculated angle of beam deflection. Phased antenna arrays built using delay lines have not only greater bandwidth, but also greater attenuation of signals. In the manufacture of phased antenna arrays with a small number of antenna elements in the range, the use of delay lines as phase-shifting elements gives a significant gain in performance with a slight loss in power. Keywords: antennas, phased arrays, radiation pattern, beamforming, phase shifters, delay line. |
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Tolkachev P.A., |
Abstract The article describes the actual problem of calculating the level of parasitic fluctuations of the phase of the output signal of the frequency synthesizer of indirect synthesis based on phase-locked loop. The basis for constructing a polynomial model is the model of output noise distribution based on the Leeson generator principle. The described principles of operation of frequency synthesizers with a divider with a fractionally variable division factor allow us to understand the nature of the appearance of the so-called shot noise. The analysis of the characteristics of all the elements included in the frequency synthesizers makes it possible to ensure that the noise components of each individual unit can be represented as a polynomial. The possibility of using the developed polynomial model for estimating the noise level in frequency synthesizers at the stage of selecting the structure of the proposed implementation structure is proposed. As a demonstration of the adequacy of theoretical calculations, the results of phase noise simulation by the polynomial method for all circuit components are presented, as well as a comparison of the results obtained with the simulation of a similar frequency synthesizer in the «ADIsimPLL» simulation package from Analog Devices. Such a simulation allows not only to obtain the level of side components in the spectrum of the output signal, but also to estimate the degree of influence of each specific element of the circuit. Keywords: frequency synthesizer, phase noise, phase-locked loop, polynomial model, digital device design. |
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MATHEMATIC MODELING |
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Ozherelkova L.M., |
The temperature dependence of unsteady heat conduction in solids 22 AbstractA mathematical model of the process of unsteady thermal conductivity of solids is proposed in the case where the dependence of the thermal characteristics of the medium (heat capacity, density and thermal conductivity coefficient) on temperature cannot be neglected in the heat conduction equation. Based on the experimental data equations of thermal conductivity are obtained for the cases of high ( ) and low ( ) temperatures (θ is the Debye temperature). Both in the case of high and low temperatures, the temperature dependences of the heat capacity and the thermal conductivity coefficient are power-law, which allows us to bring the original heat conduction equation to a form that allows the use of the classical method of variable separation in solving the corresponding boundary value problems for the heat conduction equation. The solution of the thermal conductivity equation is considered in the approximation, in which the free path of phonons is limited and does not depend on temperature, so that the temperature behavior of the thermal conductivity coefficient is determined only by the temperature dependence of the heat capacity. Exact analytical solutions for boundary value problems modeling thermal conductivity in dielectrics and metals in the polycrystalline state are obtained. The solutions relating to both areas with fixed and moving boundaries are considered. In order to solve boundary value problems with moving boundaries, in the framework of the proposed model of thermal conductivity, the functional transformation of a special kind is used. This allows reducing the original problem to the problem with fixed boundaries, but with the transformed heat conduction equation. The obtained results can be used in engineering studies of the kinetics of some physical and chemical processes in solids and liquids – diffusion, sedimentation, viscous flow, neutron deceleration, fluid flow through a porous medium, electrical oscillations, sorption, drying, combustion, etc. Keywords: equation of unsteady thermal conductivity, Debye temperature, high and low temperatures, fixed and moving boundaries. |
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Petrusevich D.A. |
Analysis of mathematical models used for econometrical time series forecasting 39 AbstractIn the paper changes of the Russian citizens’ welfare are explored. The time lapse of the data is: 2000–2018. In the first part of the paper the representative individual samples of “The Russian Longitudinal Monitoring Survey – Higher School of Economics (RLMS-HSE)” data of the 2008–2017 time period are analyzed. The 10%–95% quantiles of the salary have been constructed with the regard to year inflation, and their behavior has been analyzed. In the second part the monthly wage index based on the dynamic series of macroeconomic statistics of the Russian Federation data (2000–2018) has been explored. The mathematical models of the wage of this time lapse have been presented. They are based on the ARIMA (p, d, q) models with d≤5, p≤5. Forecasts of these models have been compared to predictions of the models with parameters p = 6 or q = 6. The constructed models have made better forecast than the automatically fitted ARIMA model with d≤5, p≤5. They have been compared using two metrics, and also the Akaike information criterion (AIC) has been considered. The seasonal factors of the wage index have been taken into account. It has been shown that the lags of 6 and 12 months are connected to the today wage index; there are maxima of this value situated at the end of the year or in summer. It’s explained with the vacations which traditionally take place in summer, and also officially held vacations in January. The further research is going to target the trend – seasonal – noise decomposition of time series. Statistical packages which are often in use have got different methods to compute the ARIMA coefficients. That fact is also going to be under research. Keywords: Russian Longitudinal Monitoring Survey, RLMS, quantiles, real salary index, ARIMA, stationarity, time series, prediction, forecast, Akaike informational criterion. |
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PHILOSOPHICAL FOUNDATIONS OF TECHNOLOGY AND SOCIETY |
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Molchanov K.V. |
Abstract The article discusses the dialectical study of the English language in the light of the work “Science of Logic” by Hegel. But this is not English language learning only – it is the study of this language in the wide sense. In the course of the study, some links between new dialectic cognition (including dialectical programming) and the English language were ascertained. The main result of our research is to identify the processes of thinking. The discussed provisions define the complex of issues relating to dialectical cognition. The results of the research can be used to develop epistemology, programming, linguistics, and psychology. Keywords: dialectics, epistemology, thinking, programming, linguistics. |
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