Journal of the Russian Universities. Radioelectronics最新文献

{"title":"Simulating the Profile of a Radio Altimeter Echo Signal","authors":"M. Borodin","doi":"10.32603/1993-8985-2022-25-4-52-62","DOIUrl":"https://doi.org/10.32603/1993-8985-2022-25-4-52-62","url":null,"abstract":"Introduction. Radio altimeters are used for remote monitoring of the Earth and sea surface based on the signal power profile, i.e. the dependence of echo signal power vs time, averaged over a set of sounding measurements. Calculation of the power profile in the presence of sea waves requires information about the probability distribution density (PDD) of sea surface applicates. The existing applicate PDD models (linear, Gram-Charlier, combined model) are characterized by certain drawbacks leading to errors in assessing sea surface parameters based on the signal power profile. In this work, the echo signal of a radio altimeter is simulated using the nonlinear Creamer model for calculating sea surface applicates.Aim. To test the validity of the non-linear Creamer model for obtaining the PDD of sea surface applicates in the problem of simulating the power profile of a radio altimeter echo signal while providing an unambiguous relationship between the statistical parameters of PDD and wind speed.Materials and methods. A two-dimensional sea surface of finite dimensions with an Elfohaily spatial spectrum was simulated in the MATLAB environment based on both linear and non-linear Creamer models.Results. Under small wind speed values of up to 3 m/s, the PDD of sea surface applicates formed by the non-linear Creamer model obey the Gauss law. For the non-linear model, an increase in the duration of an radio altimeter echo signal along with an increase in the wind speed was shown to be 5.47 % slower on average compared to that for the linear model. The time shift of the leading edge of an echo signal for the nonlinear model relative to the linear model due to the PDD transformation may reach 70 ns, which is equivalent to 10.5 m. The conducted study confirmed the validity of the non-linear Creamer model for obtaining the PDD of sea surface applicates when simulating the power profile of a radio altimeter echo signal.Conclusion. The non-linear Creamer model can be recommended for simulating an echo signal power profile for use as input data when estimating the parameters of a radio altimeter echo signal at the stage of post-processing. ","PeriodicalId":217555,"journal":{"name":"Journal of the Russian Universities. Radioelectronics","volume":"208 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117102134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diagnostics of Cognitive Development in Children by Assessing Shared Intentionality in a Biotechnical System","authors":"I. Danilov, N. I. Kurakina, S. Mihailova","doi":"10.32603/1993-8985-2022-25-4-105-115","DOIUrl":"https://doi.org/10.32603/1993-8985-2022-25-4-105-115","url":null,"abstract":"Introduction. Recent research shows that up to 17 % of children are diagnosed with cognitive developmental disorders. Early identification of developmental delay in children allows an earlier onset of treatment with greater efficiency. However, the modern diagnostic approach has limitations associated with the problem of correctly assessing behavioral markers of children. This classical assessing approach depends on specialists’ professionalism of and parents' competence in reporting the issue timely and informatively.Aim. Developing a computerized methodology and algorithm for estimating shared intentionality in mother-child dyads; designing a biotechnical system for the early diagnosis of a lag in children's cognitive development.Materials and methods. We analyze our own previous research, in which: 1) the goal was to measure the intellectual activity of a group while stimulating their shared intentionality; 2) the independent variable was the intellectual task; 3) the stimuli of shared intentionality were described. The method employs the mathematical apparatus of measurement theory, systems theory, and statistical methods of analysis.Results. The developed biotechnical system uses specific software for diagnosing cognitive delay in children during a 15-minute test. Two factors of the biotechnical system impact the object of assessment: an electromagnetic field for stimulating shared intentionality and an intellectual test. The system's software instantly provides the assessment results to the user (specialist or parents) in the form of recommendations understandable even to a non-specialist – it saves this database in a convenient form for further storage and processing.Conclusion. The advantage of the method is its unbiased computerized assessment, which can also diagnose subjects online, conversely to the classical approach based on behavioral markers. Another advantage of the assessment method is the possibility of diagnosing a lag in children's cognitive development at an earlier age, which does not yet imply verbal communication.","PeriodicalId":217555,"journal":{"name":"Journal of the Russian Universities. Radioelectronics","volume":"76 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126034651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Analysis of Mathematical Models of Tracking Radio Altimeters","authors":"A. Monakov, A. A. Tarasenkov","doi":"10.32603/1993-8985-2022-25-4-72-80","DOIUrl":"https://doi.org/10.32603/1993-8985-2022-25-4-72-80","url":null,"abstract":"Introduction. Tracking radio altimeters of low altitudes are widely used in civil aviation. These devises use periodic frequency modulated continuous wave (FMCW) signals, while altitude measurements are based on processing the beat signal processing. For this purpose, a closed automatic control loop is arranged to maintain the frequency of the beat signal at a fixed level by changing parameters of the transmitted signal (the frequency deviation or the modulation period). An alternative approach to arranging the tracking loop for altitude variations is based on the use of a phase locked loop (PLL), which adjusts the reference signal – a copy of the emitted signal – to obtain the maximum cross-correlation of the beat and reference signals. А comparative analysis of short-range radio altimeters with other currently known tracking radio altimeters for various types of frequency modulation of the transmitted signal seems to be a relevant research task.Aim. An analysis of the influence of the type of frequency modulation on the accuracy of altitude estimation in a PLL-based radar altimeter, as well as a comparative analysis of this altimeter with other known tracking altimeters.Materials and methods. Mathematical models of tracking radio altimeters are proposed, and a computer simulation of their performance is carried out for the case of altitude estimation over a smooth flat surface.Results. The conducted comparative analysis of tracking radio altimeters confirmed the effectiveness of the PLL when processing signals of different frequency modulation type (sawtooth, triangular, and harmonic FM). Altitude estimates produced by PLL-based radar altimeters are unbiased, with their standard deviation not exceeding 3 cm for the signalto-noise ratio of greater than 10 dB and under the scenario parameters adopted in the work. The conducted comparison with other tracking altimeters showed that estimation errors of this radar altimeter are an order of magnitude smaller.Conclusion. A PLL-based tracking radar altimeter can be used to estimate the height of the aircraft flight. The quality of altitude estimates produced by this device is higher than those produced by other known tracking radio altimeters. Further research and field tests will investigate the accuracy of altitude estimation when working over a rough surface.","PeriodicalId":217555,"journal":{"name":"Journal of the Russian Universities. Radioelectronics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129839341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mathematical Model of an Antenna-Waveguide Path with Separation of Signals by Frequency–Polarization","authors":"D. D. Gabriel’ean, A. E. Korovkin, S. I. Boychuk, S. Dvornikov, M. R. Bibarsov, G. S. Bibarsova","doi":"10.32603/1993-8985-2022-25-4-41-51","DOIUrl":"https://doi.org/10.32603/1993-8985-2022-25-4-41-51","url":null,"abstract":"Introduction. The creation of antenna-waveguide paths of multi-band mirror antennas (AWP MMA) is a significant task in the development of antenna-feeder devices for satellite communication systems (SSS). This task involves the construction of an adequate mathematical model of AWP MMA both without and with the implementation of an auto-tracking function built using the \"frequency separation – polarization separation\" method. However, the existing mathematical models have been developed only for specific AWP MMA types, thus making them unsuitable for the development of new AWP MMA. The model proposed in this paper can be used for an arbitrary number of combined frequency ranges and types of polarization.Aim. Development of a mathematical model of the AWP MMA of SSS both without and with the implementation of an auto-tracking function built using the \"frequency separation – polarization separation\" method.Materials and methods. The mathematical model under consideration assumes a description of the AWP MMA using block matrices. Each of these matrices describes the complex amplitudes of signals arising in each of the AWP MMA devices. This, in turn, makes it possible to analyze the influence of the parameters of each device on the characteristics of the AWP MMA of SSS as a whole with an arbitrary number of combined frequency ranges and types of polarization.Results. Two options for the construction of AWP MMA of SSS are proposed. The first option can be used in communication system antennas with software support, while the second option is applicable when a monopulse tracking method is implemented. To construct an AWP MMA model, it is proposed to use a matrix description of the characteristics of AWP MMA devices. This allows the structure of the considered AWP MMA to be varied within a wide range.Conclusion. The developed mathematical model makes it possible to describe the characteristics of each of the devices in the AWP MMA system using a certain multipole. The proposed model provides ample opportunities for controlling, at the stages of development, production and debugging, not only the characteristics of each device in the AWP MMA, but also the transmission coefficient and polarization isolation in each frequency range of the entire AWP MMA. The presented dependencies can be used to assess the relationship between parameter tolerances and the limits of changes in the characteristics of the motor vehicle.","PeriodicalId":217555,"journal":{"name":"Journal of the Russian Universities. Radioelectronics","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132321712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Algorithms for Increasing the Accuracy of Solid-State Wave Gyroscopes","authors":"K. A. Smirnov, E. A. Zarubailo","doi":"10.32603/1993-8985-2022-25-4-81-89","DOIUrl":"https://doi.org/10.32603/1993-8985-2022-25-4-81-89","url":null,"abstract":"Introduction. Wave solid-state gyroscopes (SWG) are promising sensors of inertial information used in the navigation systems of air- and spacecrafts. Over the past decade, much attention has been paid to the problem of improving the accuracy of SWGs. The accuracy of measurements performed by inertial navigation instruments can be increased by developing effective algorithms, which fact determines the relevance of the present study. Research works conducted at the JSC Research Institute of Command Instruments are aimed at developing a compensationtype angular velocity sensor (AVS) based on an SWG with a cylindrical metal resonator, an electrostatic system for excitation of oscillations and information readout, with a digital feedback.Aim. To develop methods for increasing the accuracy of SWGs based on the connection between the measurement and excitation channels, as well as accounting for the uncompensated component.Materials and methods. To obtain information about the output signal of the sensing element (SE), the fast Fourier transform (FFT) method was used. A PID controller was used to control the effect on the sensitive element.Results. Methods for increasing the accuracy of an SWG-based AVS by means of compensating the output signal errors were proposed, whose correctness was confirmed experimentally. The use of the developed algorithm for reducing the instability of the zero-velocity signal allowed its root-mean-square deviation at startup to be decreased by 76.4 %. The application of the developed method for increasing the accuracy using the uncompensated component led to a decrease in the standard deviation by 69.52 %.Conclusion. The obtained experimental results demonstrate the possibility of improving SWG characteristics significantly by using various mathematical algorithms for processing information.","PeriodicalId":217555,"journal":{"name":"Journal of the Russian Universities. Radioelectronics","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125511053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimating Disturbance Torque Effects on the Stability and Control Performance of Two-Axis Gimbal Systems","authors":"Ngoc Hung Nguyen, Van Phan Do, Hoa Tien Vu","doi":"10.32603/1993-8985-2022-25-4-63-71","DOIUrl":"https://doi.org/10.32603/1993-8985-2022-25-4-63-71","url":null,"abstract":"Introduction. Two-axis gimbal systems are applied for stabilizing and controlling the line of sight (LOS) of an optical or imaging system mounted on a moving vehicle. Gimbal systems are intended to isolate various disturbance torques and control the LOS toward the direction of a target. Two-axis gimbals can be of two main types, namely Yaw-Pitch and Swing-Roll type. In this article, we focus on investigating mathematical models of two-axis gimbals, which describe the impact of cross-disturbance torques on their stability and control performance. Simulations were conducted to compare advantages and disadvantages of the two types of two-axis gimbals.Aim. To study mathematical models describing the impact of cross-disturbance torques on the stability and control performance of two-axis gimbals.Materials and methods. Mathematical models of two-axis gimbal systems were synthesized by the Lagrange method. The operation of two-axis gimbal systems was simulated in the Matlab-Simulink environment. Results. Mathematical models and structural diagrams of the synthesized Yaw-Pitch and Swing-Roll gimbals were obtained. The conducted simulations of typical cases revealed different cross-disturbance effects.Conclusion. Motion equations for Swing-Roll and Yaw-Pitch gimbals were derived using similar methodology. The impact of cross-disturbance torques on gimbal systems was evaluated. The obtained results form a basis for selecting an optimal structure of tracking systems meeting the desired characteristics.","PeriodicalId":217555,"journal":{"name":"Journal of the Russian Universities. Radioelectronics","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116253582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Calibration Algorithm for Microelectromechanical Inertial Sensors","authors":"Nguyen Trong Yen, Nguyễn Quốc Khánh, Ha Manh Thang","doi":"10.32603/1993-8985-2022-25-4-90-104","DOIUrl":"https://doi.org/10.32603/1993-8985-2022-25-4-90-104","url":null,"abstract":"Introduction. Systematic errors of microelectromechanical (MEMS) inertial sensors, such as those related to zero drift, scale factor, and nonorthogonality of sensitive axes, are the main sources of errors in strapdown inertial navigation systems (SINS). Uncompensated sensor errors accumulate over time as motion state errors, thus reducing the overall accuracy of SINS. Consequently, calibration of inertial sensors is a relevant research task. The disadvantage of existing sensor calibration methods consists in a strict requirement for the initial alignment of sensitive sensor axes relative to a reference coordinate system, which complicates the entire process of calibration. Therefore, alternative methods for MEMS sensor calibration should be developed.Aim. To develop a calibration algorithm for microelectromechanical (MEMS) sensors, which allows calibrating sensors regardless of the angular orientation of the sensor axes relative to a reference coordinate system at the initial installation, as well as to simplify the design of testing tools.Materials and methods. Publications in national and international journals on the theory of calibration of inertial sensors were reviewed. A calibration algorithm was developed based on the least squares method.Results. An algorithm for determining the calibration parameters of sensors regardless of the initial alignment of the sensor sensitive axes relative to a reference system was developed. A simple alternative design for testing MEMS sensors was proposed.Conclusion. The method of calibrating MEMS inertial sensors proposed in this work differs from conventional calibration methods by increased reliability of the results and a simplified design of testing tools. Importantly, the results of determining the calibration coefficients of a micromechanical accelerometer (MMA) do not depend on its angular position relative to a geographic coordinate system (GСS). This works contributes to improving the accuracy of SINS based on MEMS inertial sensors.","PeriodicalId":217555,"journal":{"name":"Journal of the Russian Universities. Radioelectronics","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128766681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine Learning System for Predicting Cardiovascular Disorders in Diabetic Patients","authors":"A. Mayya, H. Solieman","doi":"10.32603/1993-8985-2022-25-4-116-122","DOIUrl":"https://doi.org/10.32603/1993-8985-2022-25-4-116-122","url":null,"abstract":"Introduction. Patients with diabetes are exposed to various cardiovascular risk factors, which lead to an increased risk of cardiac complications. Therefore, the development of a diagnostic system for diabetes and cardiovascular disease (CVD) is a relevant research task. In addition, the identification of the most significant indicators of both diseases may help physicians improve treatment, speed the diagnosis, and decrease its computational costs.Aim. To classify subjects with different diabetes types, predict the risk of cardiovascular diseases in diabetic patients using machine learning methods by finding the correlational indicators.Materials and methods. The NHANES database was used following preprocessing and balancing its data. Machine learning methods were used to classify diabetes based on physical examination data and laboratory data. Feature selection methods were used to derive the most significant indicators for predicting CVD risk in diabetic patients. Performance optimization of the developed classification and prediction models was carried out based on different evaluation metrics.Results. The developed model (Random Forest) achieved the accuracy of 93.1 % (based on laboratory data) and 88 % (based on pysicical examination plus laboratory data). The top five most common predictors in diabetes and prediabetes were found to be glycohemoglobin, basophil count, triglyceride level, waist size, and body mass index (BMI). These results seem logical, since glycohemoglobin is commonly used to check the amount of glucose (sugar) bound to the hemoglobin in the red blood cells. For CVD patients, the most common predictors inlcude eosinophil count (indicative of blood diseases), gamma-glutamyl transferase (GGT), glycohemoglobin, overall oral health, and hand stiffness.Conclusion. Balancing the dataset and deleting NaN values improved the performance of the developed models. The RFC and XGBoost models achieved higher accuracy using gradient descending order to minimize the loss function. The final prediction is made using a weighted majority vote of all the decisions. The result was an automated system for predicting CVD risk in diabetic patients.","PeriodicalId":217555,"journal":{"name":"Journal of the Russian Universities. Radioelectronics","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114957671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calculation of Band-Pass Filters with Fixed Frequencies of Infinite Attenuation","authors":"E. N. Chervinskiy","doi":"10.32603/1993-8985-2022-25-4-23-40","DOIUrl":"https://doi.org/10.32603/1993-8985-2022-25-4-23-40","url":null,"abstract":"Introduction. When calculating band-pass filters (BPF) with infinite attenuation frequencies using the frequency conversion method, the parameters of the prototype – an inverse or quasi-elliptic low-pass filter (LPF) – are recalculated into BPF parameters according to conventional formulas. Using the selected low-pass filter cutoff frequency and the Q-factor of the band-pass filter, one can select at their discretion only one infinite attenuation frequency (attenuation pole). In order to suppress a pair of concrete frequencies in the attenuation band, the synthesis of BPF should initially fix the frequencies of maximum attenuation and the central frequency of the filter. The reverse transition toward the frequency response parameters of a low-frequency prototype is carried out using frequency conversion formulas.Aim. To develop of a method for calculating band-pass filters with fixed attenuation poles.Materials and methods. Odd-order filters with an additional capacitor in the transverse branch of the П-link and an inductance in the longitudinal branch of the Т-link were used as low-frequency prototypes of the BPF with attenuation poles. Approximation of the frequency response of a low-frequency prototype (inverse or quasi-elliptical LPF) was performed by methods based on solving systems of nonlinear equations.Results. A realizable transfer function (TF) of an n-th order LPF with attenuation poles was written as the ratio of the product of binomials and a polynomial of power n with real coefficients. Systems of equations were derived to determine amplitude-frequency response coefficients with a given frequency of maximum attenuation interference for both types of filters. Analytical expressions for the TF of the low frequency prototypes of 3th and 5th orders were recorded through the capacitances of the BPF circuits tuned to the central and suppressed frequencies, thus allowing the desired capacitances to be directly calculated. The BPF inductances were determined by formulas expressing the dependences of the BPF central frequency on the circuits parameters, taking into account the relationships given in the article. An example of calculating a 10th order quasi-elliptic BPF was provided.Conclusion. The proposed method can be used to determine the BPF parameters directly, without an intermediate calculation and subsequent transformation of the LPF prototype parameters. The given analytical expressions for the frequency response of the П- and Т-shaped BPFs of the 6th and 10th orders make it possible to verify the performed calculations and to correct the frequency response using inductances, when replacing the calculated capacitance values with their standard values.","PeriodicalId":217555,"journal":{"name":"Journal of the Russian Universities. Radioelectronics","volume":"230 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128619969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing the Shape of Signals with Quadrature Amplitude Modulation According to the Criterion of Given Reduction Rate of Out-of-Band Emissions","authors":"S. Makarov, S. Zavjalov, A. Ovsyannikova","doi":"10.32603/1993-8985-2022-25-4-6-22","DOIUrl":"https://doi.org/10.32603/1993-8985-2022-25-4-6-22","url":null,"abstract":"Introduction. The growth in the volume of information transmitted through communication channels leads to their significant congestion. Almost all methods conventionally used to increase the data transfer rate in given frequency bands have been exhausted. In this regard, it is of interest to use new approaches aimed at improving the spectral efficiency of radio engineering and telecommunication systems by applying optimal signals that make it possible to use the bandwidth reserves of transmission channels given by Shannon's theory.Aim. Improvement of the spectral efficiency of digital messaging systems by using signals with a compact spectrum and increased volume of the channel alphabet at the same time as minimizing energy losses.Materials and methods. When searching for optimal signals, the mathematical apparatus of communication theory and functional analysis, as well as the methods of calculus of variations, were used. The evaluation of bit error rate performance of the obtained optimal signals transmitted in a channel with additive white Gaussian noise was performed in the MatLab environment. Results. It was established that, in a channel with additive white Gaussian noise, optimal signals with a signal constellation size of 64 in the case of quadrature amplitude-phase modulation provide an energy gain of more than 1 dB relative to signals obtained by narrowband filtering under the conditions of uncontrolled intersymbol interference. Optimal signals were shown to provide for an energy gain of 4.9 dB with respect to signals based on narrow-band filtering at a fixed spectral efficiency of 7 (bit/s)/Hz.Conclusion. The paper proposes a method for improving the spectral efficiency of quadrature signals with amplitudephase modulation, based on the use of optimal pulse shapes obtained as a result of solving an optimization problem. The optimization problem was solved according to the criterion of minimizing out-of-band emissions with the constraint on bit error rate performance in case of amplitude-phase modulation. The energy and spectral efficiency of signals with optimal pulse shapes and signals based on narrow-band filtering were compared.","PeriodicalId":217555,"journal":{"name":"Journal of the Russian Universities. Radioelectronics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131157286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}