For authors
Search
Search Results
##search.searchResults.foundPlural##
-
RESEARCH OF THE CHARACTERISTICS OF THE NOISE SIGNAL CONDITIONER AS A NOISE SOURCE IN MULTI-CHANNEL NOISE GENERATORS
P.A. Zemlyanukhin , A. V. Kondratiev, S.S. Svidelsky2021-01-19Abstract ▼The purpose of this work is to study the principle of operation and characteristics of a modulation-
type noise signal conditioner in which quasi-harmonic noise signals are used as a carrier
oscillation and modulating signal and in which the spectrum width of the noise signal is controlled
in a given frequency range. A study of the structure of the construction characteristics of the noise
signal generator that can be used to create adaptive multichannel noise generators to provide
active protection of informative components of side electromagnetic radiation and interference
(SERaI). According to the sources of domestic and foreign literature, as well as patent documentation,
the analysis of technical solutions for the implementation of noise generators intended for
masking SERaI were analyzed. The analysis confirmed the relevance of the problem of creating
adaptive noise generators. It is noted that it is necessary to create multichannel adaptive noise
generators to improve the characteristics of noise generators and make them more widely used in
order to effectively counteract unauthorized leakage of information by hackers through the SERaI
radiation channels. In these generators, each noise channel can be adjusted for power, generated
noise signal and control of the noise masking frequency bandwidth, which will increase the electromagnetic
compatibility of such devices. To ensure this, it is proposed to use two analog signalmultipliers in the noise signal conditioner, from the outputs of which the noise signals are summed
and sent to the output of the noise signal conditioner which allows to obtain a uniform noise signal
in amplitude. It provides control over the spectral width of the noise signal at least twice as compared
to traditional methods of generating a noise signal using modulation methods. -
ADAPTATION OF INFORMATION AND TECHNICAL CHARACTERISTICS TO THE CONSTANTLY CHANGING PARAMETERS OF IONOSPHERIC PROPAGATION
A.I. Rybakov, R.E. Krotov, S.A. Kokin2020-07-20Abstract ▼The aim of the research work was to study and select the existing adaptation options for
transmission parameters, in order to reduce the influence of shortcomings of the short-wave radio
line, it is advisable to use the methods of digital signal processing as efficiently as possible. According
to the results of the characteristics of analog-to-digital converters (ADCs), it became a
study of the available hardware for constructing extended radio links, it was concluded that with
an increase in the performance of FPGAs on which digital signal processing is implemented, it is
possible to implement the technology of creating an active antenna array (AAR), consisting of the
Nth number of independent antenna modules, which is a conceptual task in solving the issue of
adapting information and technical characteristics to constantly changing parameters of
ionospheric transmission, for a more energy-efficient approach to designing an ionospheric radio
communication system. Improving the performance of the radio system by improving communication
protocols, solving the problem of optimal channel load from the time of formation and reception
of signals. The main idea of such an AAR is to digitize or generate a high-frequency signal in
the immediate vicinity of the antenna, as part of the antenna modules. The indicated results make
it possible to replace separately tuned radios and transceivers built according to a complex superheterodyne
circuit with a limited number of available hardware units operating under software
model of a software-configurable radio channel. In the next work, it is planned to conduct studies
to assess the passage of OFDM signals through multipath communication channels with fading of
Rayleigh and Rice. The resulting model will allow us to evaluate the noise immunity at different
lengths of the cyclic prefix of the OFDM symbol and to observe the behavior of the signal constellation
under the influence of various instabilities. -
REALIZATION OF METHODS FOR SYNCHRONIZATION OF DATA FLOWS IN DIGITAL SIGNAL PROCESSING SYSTEMS
I.I. Levin , D.S. Buryakov119-1342025-07-24Abstract ▼In digital signal processing applications involving coherent processing of data from a phased antenna array, it is important to ensure the coordinated arrival of digitized data from antenna elements to processing units. As the number of data transmission channels in DSP complexes grows, the probability of errors in the data transmission channels increases significantly, which puts forward increased requirements to the assurance of the program complex of isochronous data transmission. The paper presents the results of the development and realization of methods that increase the assurance of isochronous data transmission. A combined method of isochronous data transmission is proposed, characterized by the use of service gaps in the transmission of operand arrays and dynamic compensation of delays in data channels. The most probable errors occurring during data transmission are singled out and methods of their parrying are proposed. A program complex realizing the combined method is described. Using the attributive model of dependability, the dependability of the program complex is analyzed. The analysis has shown that the use of the combined method will quadruple the number of data transmission channels in the DSP complex at a given level of dependability and fixed time of reliable operation in comparison with the basic method. With a significant increase in the number of data channels, there is a need to maintain a given level of dependability. In this regard, a modernized method of isochronous data transmission is proposed, in which the algorithms for checking data integrity, checking the acceptable range of delay mismatch in the data channels and the algorithm for switching the reference channels were improved. An evaluation of the implementation dependability of the modernized method showed its ability to provide twice the number of data channels compared to the combined method.
-
DETERMINATION OF TARGET COORDINATE ERRORS IN MULTI-POSITION RADAR USING GROUPS OF UNMANNED AIRCRAFT
I.V. Borisov , А.S. Kuzmenko , V. Е. Kuryan , Е. М. Levchenko , М.V. Kuryan273-2842025-07-24Abstract ▼The article proposes and develops an algebraic method for determining the coordinates of targets and their errors as part of a group of unmanned aerial vehicles. The main assumptions of the developed model of the functioning of a group of unmanned aerial vehicles: The speeds of aircraft do not exceed the speed of sound in the air, and the speeds of targets do not exceed the first space were justified. The main assumptions of the model of operation of a group of unmanned aerial vehicles: the UAV speeds do not exceed the speed of sound in the air, and the target speeds do not exceed the first space one, are justified in the article. Qualitative estimates of the radar signal reception time for a given spatial error of the target coordinates were presented. The conditions for the number of aircraft in the group are formulated, which increase the accuracy of determining the location of the target in space. The various types of errors that arise when organizing the search for targets by a group of aircraft are analyzed. The issues of dependence of the resulting error in calculating the coordinates of the search target on the error in measuring the distance between the aircraft in the group and the target itself, depending on their mutual spatial orientation, are investigated. An algorithm has been developed, calculations and analysis of the results for this task have been carried out. The simulation is based on the proposed algorithm, taking into account random coordinates of the target in a fixed sector and taking into account random errors in the measured distance between a group of aircraft and the search object. The results of modeling the influence of the configuration of a group of unmanned aerial vehicles and the location of the target on the error in determining its coordinates are presented. An assessment was carried out to determine the coordinates of the goals and an error estimate of the proposed algebraic approach. The ways of further research are determined. The issues of estimating the amount of calculation for a large number of goals are considered.
The scope and effectiveness of the proposed algorithm and method for solving the problem as a whole are determined. -
DEVELOPMENT OF ENERGY EFFICIENT COMMUNICATION SYSTEM IN THE TROPOSPHERE RADIO CHANNEL BASED ON OFDM SIGNALS
P.V. Luferchik, P.V. Shtro, А.N. Konev, А.А. Komarov2022-11-01Abstract ▼It is known that inter-symbol interference may occur during data transmission in radio relay
and tropospheric communication systems. The presence of multipath propagation and frequencyselective
fading in the tropospheric, radio relay channel significantly reduces the energy efficiency
of the communication system as a whole. The aim of the work was to increase the efficiency of
using the channel for radio relay and tropospheric communication by using OFDM (orthogonal
frequency-division multiplexing using the methods of reducing the peak factor of the OFDM signal
and increasing the linearity of the transmission path. To evaluate digital predistortion algorithms
in the Matlab/Simulink environment, a model was developed for the LMS, NLMS, RLS, RPEM
methods and a power amplifier model with real characteristics. Based on the results of modeling
algorithms, RLS was chosen. In addition, in this work, a modified version of the adaptation algorithm
based on the recursive least squares method (RLSm) was developed. The main result of the
modification is: a decrease in the number of arithmetic operations per iteration (more than
5 times), an increase in the stability of adaptation algorithms, due to the introduction of regularization
methods, a decrease in the convergence time, due to the introduction of an exponential dependence.
Various algorithms for reducing the peak factor of an OFDM signal were investigated,
the best result was achieved by combining Tone reservation (TR) and Active constellation extension
(ACE). Simulation in the Matlab/Simulink environment showed that the combination of TR
and ACE algorithms reduces the peak factor of OFDM signals by ~5dB for BPSK data stream and
~4.5dB for 8-PSK, QAM-16, QAM-64, QAM-128 and QAM- 256. To increase the linearity of the
transmission path, the RLSm digital pre-distortion algorithm was selected and upgraded, it made
it possible to reduce the magnitude of the error vector modulus (EVM) by 13.5dB, and also increase
the modulation/error ratio (MER) by 13.6dB. -
EXPERIMENTAL STUDY OF A PROTECTIVE DEVICE
А.V. Andrianov, D.Е. Gubarev, А.N. Zikiy, P.N. Zlaman263-2702025-07-31Abstract ▼The protective device (limiter) at the receiver input is an important component, as it ensures
the safety of the receiver operation in conditions of receiving powerful signals. The results of an
experimental study of a protective device in the 1-4 GHz band are presented. It is shown that the
minimum bandwidth losses at a low power level do not exceed 0.63 dB, the maximum bandwidth
losses are 1.23 dB. At an input power of 25 dBm, the protective device operates in a non-linear
mode, therefore it creates harmonics of the input frequency. The experimental amplitudefrequency
response (AFC) of the protective device, as well as amplitude characteristics at three
frequencies are presented. The experiment to remove the frequency response was carried out on a
vector analyzer of circuits. The experiment to remove the amplitude characteristics was carried
out using a standard signal generator and a spectrum analyzer at three frequencies: 1 GHz;
2 GHz; 4 GHz. Structurally, the protective device is a polycor substrate on which all elements
except connectors are placed. The substrate is placed in a frame-type housing and closed with two
sealed lids. Type III sockets according to GOST13317- 89 are used as connectors. A schematic
diagram and a brief description of the design are given. The following main parameters have been
achieved: losses do not exceed 1.23 dB in the operating frequency range from 1 to 4 GHz, the output signal power at a high input power level (f = 1 GHz; Rvh = 25 dBm) does not exceed
12 dBm. The protective device is recommended to be used in the input circuits of communication
receivers, navigation, radar and electronic warfare -
IMPROVING THE EFFICIENCY OF HIGH-PERFORMANCE FREE SPACE OPTICAL COMMUNICATION CHANNELS IN VARIOUS WEATHER CONDITIONS
S. V. Zhilin, V.V. Arkhipenko, Е.S. Basan, М.Y. Polenov114-1262025-08-01Abstract ▼A common problem of traditional radio communication channels - the lack of free frequencies,
noise, low bandwidth, the need to obtain a license to use the frequency, the relative ease of hacking.
Free space optical communication channels overcome these limitations, is one of the types of communication
systems that use open space to transmit information carried by light - this points to the
need for direct visibility of the transceivers. Due to the influence of various weather conditions, the
light flux is subject to atmospheric attenuation. In this paper, a method to improve the efficiency of
high-performance wireless optical communication channels in different weather conditions: clear
sky, fog, rain and snow was investigated. The existing wireless optical communication technology, a
dense multiplexing multiplexing (DWDM) system with one input and one output (SISO), was considered.
And it was proposed to improve the existing system by applying multiple input/output (MIMO).
An impact and attenuation analysis on the wireless optical network in different weather conditions was conducted. The study was based on the use of the Optisystem simulation software toolkit, which
is used to emulate different weather conditions of attenuation in two types of systems. Models were
developed for each of the optical communication systems studied. A comparison between SISO and
MIMO systems is made in terms of quality factor under different weather conditions. The proposed
system shows promising results in terms of performance and received signal quality. The transmission
path length of the proposed system in dense fog conditions increases by 33.6%. The transmission
path length of the proposed system in heavy rain increases by 63.89%. The transmission path
length of the proposed system in heavy snow increases by 35,21%. -
AN IMMUNOLOGICAL MODEL OF TEXT-INDEPENDENT VOICE IDENTIFICATION
Y.A. Bryukhomitsky6-132022-05-26Abstract ▼An immunological model of clonal selection with positive selection based on the principles
of mass-parallel data processing used in artificial immune systems, is proposed. The model is
designed for text-independent identification of a person by voice. In contrast to known passwordbased
voice identification systems, the proposed model implements decentralized recognition of
voice data by matching it with detectors that simulate immunocompetent cells of the immune system.
The initial voice features are generated in a linear speech predictor and are represented by
cepstral coefficients. The sequence of cepstral coefficients is further divided into equal time sections
- morphemes, which are abstract linguistic units that unify phonemes. Morphemes carry the
individual coloring of consecutive temporal segments of speech reproduced by the voice, allowingthem to be used productively as voice identifiers. The matching of voice morphemes with detectors
is carried out according to the principle of positive selection based on the Euclidean proximity
measure. The model's "friend-or-foe" identification decision making is implemented on the basis of
a statistical approach in terms of the frequency of detector response. The proposed model implements
the identification of the speaker's personality at the rate of receipt of his voice data. At the
same time, personality identification is invariant to the language, volume and content of speech.
The advantage of the model is complete protection against replay attacks. The effective realization
of the model, the accuracy and speed of identification are due to the possibility of organizing highspeed
analysis of large volumes of voice data, which in the long term corresponds to the pace of
development and application of high-performance computing systems. -
DIGITAL SIGNAL PROCESSING IN A PASSIVE MULTI-POSITION RADAR, CREATED ON THE BASIS OF THE UAV GROUPING
I.I. Markovich, Е.Е. Zavtur, А.I. Panychev6-172025-08-04Abstract ▼The expediency of creating a passive multi-position radar based on a grouping of unmanned aerial vehicles is substantiated. The variant of building of such radar is proposed, the main tech-nical problems of the sonar developing are evaluated and possible ways to overcome them are considered. It is shown that for detecting aerial targets and determining their coordinates from the radio emission of on-board equipment, the difference-rangefinder method is the most promis-ing as it does not depend on signal modulation and is potentially resistant to interference. For small-sized UAV for transmitting information over open radio channels, the typical frequency ranges are 2.4 and 5.0 GHz. A block diagram of a passive multi-position radar has been devel-oped, including digital shapers of the quadrature components of the received signal, blocks for detecting and determining the coordinates of the target. The main parameters are calculated and analytical expressions of digital signal processing algorithms for detecting and determining the coordinates of the target are given. A stroboscopic effect is used in the digital quadrature compo-nent shaper, which allows for bandpass signals to select the sampling frequency not by the upper boundary frequency of the spectrum, but by its width, which significantly reduces the requirements for the performance of the ADC and the DSP devices following it. The complex envelopes of the detected signals are generated by the method of digital generation in the time domain using digital low-frequency filters. The detection of signals is performed by an energy detector, the advantages of which are simplicity of implementation and operability in the absence of a priori information about the received signal. To determine the coordinates of the radio source, signal delays are calculated between pairs of signals received by three UAV from a multi-position radar, which are determined by the maximum modulo values of the mutual correlation functions of the signals in these pairs. It is shown that the proposed algorithms are well adapted to the processing of possible sources of radio emission on board small-sized UAV. It is established that the required perfor-mance of the radar computer for real-time operation does not exceed 84.62 GFLOPS. The design of an on-board antenna module of a passive multi-position radar in the form of a microstrip re-configurable antenna, tunable in frequency and polarization, is proposed.
-
CIRCUIT AND ELECTRODYNAMIC SIMULATION OF THE OSCILLATORY PROCESS OF ENERGY REDISTRIBUTION IN A BIPOLAR TRANSISTOR
К. А. Boikov2022-03-02Abstract ▼The advantage of the promising method of passive radiosensor technical diagnostics
(PRTD) over the currently existing methods for determining the technical condition (vibrometry,
thermal control, JTAG-testing, optical control) are: no inertia, no processor time, no galvanic
contact with the object of study. In modern scientific literature, almost no attention is paid to numerical
models of electronic devices, including those based on bipolar transistors (BPT), which
describe the process of oscillatory redistribution of energy and radiation used in PRTD. Therefore,
the purpose of this study is to develop the PRTD method through the development, analysis
and comparison of circuit and electrodynamic models of oscillatory energy redistribution in the
BPT. The paper presents and analyzes simplified circuit and electrodynamic models of oscillatory
redistribution of energy in the BPT. The parameters of the models are calculated signal radio
profiles (SRP) are obtained for the electrical component of electromagnetic radiation created by
the radio-electronic unit itself, built on the BPT. Methods for adjusting the reference parameters
depending on the actual conditions for switching on the BPT are shown. It has been established
that the cross-correlation function of the SRP obtained as a result of circuit and electrodynamic
modeling is not lower than 0.93, which indicates a high similarity of the presented models. In
practice, the use of the developed models in the analysis of SRP obtained by recording the intrinsic
emissions of radio engineering components of electronic devices will allow us to determine the
operating mode of the BPT and its speed with a sufficiently high accuracy. This analysis can be
used in the PRTD, indicating a malfunction of the signal circuits, or degradation of the parameters
of the element itself in the early stages -
ANALYSIS OF CERTAIN WEIGHT FUNCTIONS (WINDOWS) AND THEIR APPROXIMATIONS FOR IMPLEMENTATION OF CONTROLLED RECURSIVE LOW-PASS FILTERS WITH A FINITE IMPULSE RESPONSE ON THEIR BASIS
T.V. Shushkevich , А.А. Morozov, I. I. Turulin2021-11-14Abstract ▼There are various types of weighting functions, the so-called windows in digital signal processing,
such as rectangular (Dirichlet window), triangular (Bartlett window), Vallee-Poussin window,
Kaiser-Bessel window, Barsilon-Temesh window, Hann, Bohman, Blackman, Gauss (Weierstrass),
Dolph - Chebyshev, Hamming windows and many others and ideal characteristics of standard filters
such as low-pass, high-pass, bandpass filters. The purpose of this review article is to determine the most
suitable weighting function for implementation on its basis of a controlled recursive low-pass filter with
a finite impulse response. This article presents an analysis of only some of the above windows and their
approximations, namely the Dolph - Chebyshev window, the Gauss (Weierstrass) window and the
Hamming window. In addition to the analysis, the synthesis of recursive filters with a finite impulse
response for weighting data based on the selected windows and their approximations was considered.
The method of synthesis of Dolph-Chebyshev windows is considered. The implementation of the Gauss
(Weierstrass) window is considered. Methods for approximating the Hamming window and methods
and several algorithms for developing filters with FIR in the form of this window are considered. The
estimation of parameters dependencies some quick window of the maximum level of the side lobes.
Based on the data obtained, conclusions were drawn about the selection of the most suitable and
demonstrating maximum performance windows, suitable for implementation on its basis of a controlled
recursive low-pass filter with a finite impulse response. -
SCALING OF INTEGER DATA IN RECONFIGURABLE COMPUTER SYSTEMS WHEN CALCULATING A RADAR RANGE-VELOCITY PORTRAIT
O.V. Ershova, E.V. Kirichenko, M.S. Kocherga, E.A. Semernikov2021-02-25Abstract ▼This article deals with the question of preventing overflows of the bit grid in highperformance
reconfigurable computing systems based on FPGAs, leading to fatal data processing
errors when obtaining a radar range-velocity portrait of the target. The known methods of solving
this problem are briefly considered. A new method for a priori determination of the number of
scaling points in pipeline-parallel computing structures that form the target's radar range-velocity
portrait is proposed. This technique allows to determine in advance the required number of scaling
points at all stages of integer data processing and to prevent overflows when calculating theFFT (IFFT) in all possible situations. An algorithm of forming of range-velocity portrait from an
initial signal matrix is considered by the example of a continuous-wave radar system with linear
frequency modulation (LFM). Formulas for calculating the maximum value of the amplitude of the
converted signals at all stages of obtaining the range-velocity portrait and the number of iterations
with scaling in the FFT (IFFT) procedures are given. A numerical example of calculating the
number of scaling points for all stages of the algorithm of range-velocity portrait formation is
presented. In the example the required number of iterations with scaling is determined when calculating
the fast convolution and Doppler velocity (taking into account multiplication by the window
function). It allows to prevent signal values from going beyond the bounds of the bit grid. As a
result, it was found that the proposed method for calculating the number of scaling points avoids
an excessive drop in the signal level at the processing output and reduces the ratio of digital processing
errors to the signal level of the range-velocity matrix. -
MULTYCHANEL ADAPTIVE PHASE LOCK LOOP SYSTEM FOR GNSS RECEIVER
А. А. Cherkasova, А. Y. Shatilov2025-04-27Abstract ▼Satellite navigation equipment often operates under conditions of a priori uncertainty of the parameters
of the mutual dynamics between the transmitter and the consumer and the signal-to-noise ratio of the
received signals of satellite radio navigation systems. Classical Bayesian algorithms for Phase lock loop
system require a priori knowledge about the parameters of the phase process dynamics and the signal-tonoise
ratio (SNR) of the received signals. As a result, the operation of such algorithms under conditions
other than that a priori specified is not optimal to the criterion of minimum error variance. Moreover, a
sudden change in the signal-to-noise ratio or dynamics can lead to a tracking failure in such a system.
The purpose of this work is to develop an optimal phase tracking system that is adaptive to the dynamics
of the phase process and the signal-to-noise ratio in order to maintain phase tracking in the widest possible
range of operating conditions while tracking global navigation satellite system signal. An adaptive
multichannel phase lock loop system has been synthesized as a result of formulation and solution of signal
processing problem in terms of the statistical synthesis theory. Adaptivity to the changing power of the
received signal is achieved by including the signal-to-noise ratio [dBHz] in the vector of estimated filter
parameters. Adaptability to the intensity of the phase change dynamics is achieved through the use of a
multi-channel filtration system. Statistical modeling of an adaptive multichannel phase lock loop tracking
system with a complex algorithm for tracking the code delay of the signal of satellite radio navigation
systems has been carried out. The values of the sensitivity of phase tracking under various dynamic conditions
are determined. The adaptive multichannel phase lock loop system is able to withstand an signal-tonoise
ratio jump from 50 to 10 dBHz and back without loss of phase tracking in low dynamics conditions
(only the drift of the reference quartz oscillator). The AMPLL system is able to withstand abrupt transitions
of dynamics between low and high (the sinusoidal acceleration 10g and sinusoidal jerk 10 g/s) without
loss of phase tracking under the 24 dBHz signal-to-noise ratio. Thus, in real conditions, when the dynamics
of the GNSS receiver and the SNRs of the received signals change in an unpredictable way, the
AMPLL system keep tracking in a much wider range of conditions than the non-adaptive PLL -
OPTIMIZATION OF REMOTE DOPPLER RECEIVER’S PARAMETERS IN SEMI-ACTIVE RADAR SYSTEMS
P.A. Dyatlov, K.K. Bagrat2021-02-13Abstract ▼This article discusses the issues of increasing the noise immunity of semi-active radar systems
based on the use of transmitters for target illumination using harmonic radiation and remote
Doppler receivers in conjunction with a central information processing station. This solution is
not only the simplest from the point of view of hardware implementation, but also has such advantages
as high speed and increased sensitivity, as well as the ability to search-free spatial and
frequency processing of radiation. Of the shortcomings, it should be noted the low secrecy of the
functioning of this semi-active radar system. The purpose of the work is to eliminate the indicated
drawback by using frequency tuning in the illumination transmitter or when using several spaceseparated
illumination transmitters operating according to a given frequency-time scheme in a
semi-active radio-location system. In addition, the paper deals with the optimization of the main
parameters of portable Doppler receivers of semi-active radar systems. In particular, the paper
gives recommendations for reducing the blinding effect of a direct signal to a Doppler receiver
and presents a set of measures aimed at increasing the range of action of semi-active radar systems
up to forty kilometers. In this paper, we consider the case of operation of a semi-active radiolocation
system operating in a limited spatial sector using one remote receiving point. The illumination
transmitter, which is usually placed on a high-rise object, generates directional radiation,
intended primarily for solving various tasks in the field of telecommunications, for example,
providing mobile communications, relaying satellite information, etc. In this system, the illumination
transmitter is used in as a signal generator for illumination of air targets -
EVOLUTION OF RADIO OVER FREE SPACE OPTICAL COMMUNICATION UTILIZING SUBCARRIER MULTIPLEXING / AMPLITUDE SHIFT KEYING
Hussein Ahmed Mahmood, Al-Karawi Hussein Shookor, K. Y. Rumyantsev2021-01-19Abstract ▼The high demand for increased bandwidth, data rate and quality in optical communication
systems in modern applications. Radio over free space optics (RoFSO) is deemed a new design
methodology over wireless systems and networks. This technique has to ensure data rates like ones
presented by means optical fiber communication techniques in keeping with a portion of its arrangement
cost. Such systems are implemented by combined radio signal (RF) with optical signal,
which containing various wireless administrations and Free Space Optics (FSO) link. In this paper,
the simulation and evaluation system of Subcarrier Multiplexing/Amplitude Shift Keying
(SCM/ASK) transmitter for Free Space Optical Communication is proposed. 1Gb/s data Rate given
to the system. Whilst 10 GHz radio frequency signal setting in electrical amplitude modulator.
Thereafter, radio signal is added with 100 subcarrier channels of 10 MHz spacing channel at
operated first channel frequency of 60 MHz. These subcarrier channels with 900 combined with
10 GHz sin wave signal ( radio frequency ) at hybrid coupler, the combination of each subcarriers
and radio signal are modulated by LiNb Mach-Zehnder optical modulator with 1550 nm wavelength
continues wave laser signal at 10 dBm input power. The optical modulated signal (after
optical modulator) is transmitted over a various free space optical link from 300m to 1km under
the Atmospheric turbulence effect (the structure feature of the refractive index). The system is
evaluated utilizing Opti system software with Q-factor and BER terminology. It is shown that the
maximum optical distance for weak turbulence (
at BER equal to 10-9 is
950m, while the maximum optical distance for strong turbulence
is 850m. -
ANALYSIS OF STABILITY AND FEATURES OF PRACTICAL IMPLEMENTATION OF HOGENAUER FILTERS AS RECURSIVE DIGITAL FILTERS WITH FINITE IMPULSE RESPONSE
I.Е. Moiseenko , S. P. Tarasov , I.I. Turulin37-462025-10-01Abstract ▼The article considers the issues of stability of cascade integrator-comb (CIC) filters used in digital signal processing, including decimation and interpolation. A brief review of modern publications on the architectural optimization of CIC filters is given. The main attention is paid to increasing the stability of filters to the overflow of the bit grid, analyzing their stability and the method of synthesis of recursive FIR filters (filters with a finite impulse response). For a better understanding of the nature of the stability of CIC filters, the paper presents mathematical calculations illustrating the features of the accumulation of the constant component for various block configurations. A change in the structure of the CIC filter is proposed, consisting in the permutation of the integrator and comb filter blocks. It is proved that such a change prevents the accumulation of the constant component of the signal in the integrators and, therefore, eliminates the overflow of the bit grid due to the accumulation of the constant component in the integrator. This approach is based on the property of linear filters, according to which changing the order of inclusion does not affect the transfer function. amplitude-frequency characteristic, but in the case of digital implementations it allows to significantly reduce the probability of overflow. The possibilities of hardware and software implementation of such structures are considered from the point of view of minimizing the loss of accuracy and increasing the reliability of digital signal processing systems. It is proposed to use integers or numbers with a fixed point to eliminate the accumulation of quantization errors. In addition, a program in Python was developed that implements a CIC filter taking into account the stability of the constant component in the input signal and the accurate execution of operations. The obtained results are compared with modern approaches presented in scientific research in recent years. The proposed solutions can be useful in developing digital filters for systems with limited computing resources and increased stability requirements.
-
DEVELOPMENT AND RESEARCH OF THE EQUALIZER CONFIGURATION TO INCREASE NOISE IMMUNITY IN DECAMETER RADIO LINES
А. I. Rybakov212-2272025-10-01Abstract ▼The problem of increasing the noise immunity of decameter radio lines (DRL) in modern domestic radio communication systems, including short-wave (SW) communication, remains significant and in demand, despite the existence of numerous classical studies. The decameter radio communication systems have been chosen as the object of our analysis. Specifically, the R-016 system, which is used as a prototype, faces limitations such as its frequency range, which affects its effectiveness in conditions of variable ionospheric characteristics that negatively impact the signal level. Signal processing issues in prototypes can lead to bit errors reaching a bit error rate (BER) of 10-3, even in the absence of significant interference. The main objective of the study is to evaluate the impact of various factors, such as changing the length of the preamble and implementing adaptive filters, on the noise immunity of systems. The analysis of the results indicates that increasing the length of the preamble improves the noise immunity of decameter radio lines. The practical significance of the results is that they can be used to improve the noise immunity of existing DFM radio communication systems that operate in variable ionospheric conditions. This paper also discusses the scientific basis for selecting an equalizer configuration for decameter radio lines to increase communication range and improve noise immunity. The developed methods provide a scientific basis for selecting effective equalizer settings, which can lead to improved communication range. To test different equalizer configurations in a Rayleigh channel, Simulink simulation is used, which confirms the correctness of the selected parameters. Experimental validation of the decameter radio line model includes the study of various preamble lengths, and the analysis of signal-to-noise ratios (SNR) at the receiver input allows for the adaptation of these parameters. Thus, the research results show that increasing the preamble length has a positive impact on the system's noise immunity. The work focuses on the modeling and operation of DFM radio lines, and the obtained results have practical significance for the active adaptation of existing radio systems in a changing ionosphere
-
GENERATION OF COHERENT OPTICAL RADIATION MODULATED BY A QUADRATURE PHASE-SHIFT KEYED RADIO SIGNAL
А. S. Mamitov , К.Е. Rumyantsev207-2202025-12-30Abstract ▼The use of broadband optical amplification, wave division multiplexing, dispersion compensation of optical radiation, and differential phase-shift keying enables data transmission at rates of up to 40 Gbit/s. Prospects for further increasing transmission rates to 100 Gbit/s are associated with the use of multilevel modulation formats for radio signals on multiple subcarrier frequencies, modulation of the radiation from a single optical quantum generator by radio signals on multiple subcarriers, balanced homodyne detection of coherent optical radiation, and digital signal processing. Symbol-based transmission via quadrature phase-shift keying (QPSK) provides high data rates. Prior studies have substantiated the use of a single-sideband coherent optical radiation generation algorithm with subcarrier QPSK modulation. Due to hardware instabilities, amplitude and phase errors may arise, leading to quadrature imbalance. These inaccuracies introduce additional errors during demodulation of the received signal, which can significantly degrade reception interference immunity. The aim of this study is to analyze the process of generating single-sideband optical radiation modulated by a QPSK radio signal on a subcarrier frequency using two parallel Mach–Zehnder interferometers. A distinguishing feature of the proposed approach is that the derived mathematical relationships make it possible to subsequently assess the impact of amplitude and phase errors in quadrature signal generation (quadrature imbalance) on reception quality.
-
RECOGNITION OF EMOTIONAL STATES IN RUSSIAN SPEECH USING MFCC FUNCTIONS AND THE BLSTM MODEL FOR THE DUSHA DATASET
P.G. Bukina , А.А. Merinov , S.S. Kharchenko , Е.Y. Kostyuchenko240-2482025-12-30Abstract ▼This paper investigates the task of automatic emotion recognition from speech signals using contemporary deep learning techniques. The relevance of this study arises from the increasing demand for intelligent systems capable of assessing human emotional states, with potential applications in medicine, psychology, information systems, and personnel management. The primary objective is to develop an efficient neural network model for emotion recognition in Russian speech that outperforms existing state-of-the-art architectures. The experiments were conducted using the open-source Russian-language dataset Dusha, which contains 300,000 audio recordings. A total of 183,055 samples from the Crowd subset, annotated with four emotional categories—joy, sadness, anger, and neutral state—were used for training. Mel-frequency cepstral coefficients (MFCCs) were extracted as input features (20 coefficients with a
20 ms window and 10 ms overlap), followed by normalization. The baseline architecture employed a bidirectional long short-term memory network (BLSTM), capable of modeling both past and future temporal dependencies. To improve generalization and mitigate overfitting, the model was enhanced with convolutional layers (CNN), MaxPooling layers, and regularization mechanisms including Dropout and Batch Normalization. The resulting hybrid CNN–BLSTM architecture achieved 62.9% accuracy on the test set, exceeding the baseline performance (56.2%) by 6.7%. The results were further compared with state-of-the-art architectures such as MobileNetV2, HuBERT, and WavLM. The analysis highlights future directions for improving model performance through structural optimization, class balancing, and incorporation of additional acoustic features. -
MODEL OF KEY SEQUENCE GENERATION IN A COHERENT DUAL-BAND OPTICAL SYSTEM WITH PHASE-SHIFT KEYED RADIO SIGNAL MODULATION
К. Y. Rumyantsev , D.А. Tsytsorin2026-02-27Abstract ▼Coherent optical communication using quadrature phase-shift keying (QPSK) provides high-speed data transmission using in-phase and quadrature (IQ) modulation formats over long distances. A quadrature optical modulator with two Mach-Zehnder interferometers in a two-way configuration with simultaneous phase shift in its arms significantly improves the technical characteristics and ensures the electromagnetic compatibility of digital signal transmission paths. The two-cycle configuration of an optical modulator is the basis for high-speed and noise-resistant data transmission. The research results prove that, after certain corrections to the known coherent optical transmission structures, the system can be used for key distribution. The structure of a coherent two-band optical key sequence formation system is presented. The model for generating optical radiation with modulation by a phase-shifted radio signal is based on a quadrature optical modulator with two parallel Mach-Zehnder interferometers with constant bias voltages on all control electrode arms. Key sequence formation is implemented by modulating the in-phase and quadrature components of radio signals at the subcarrier frequency. A set of two amplitude multiplication coefficients for each bit is specified by the electronic encoding device. The coefficients represent the signals that modulate the amplitude of the in-phase and quadrature components of the subcarrier frequency, respectively. The optical radiation generated at the modulator output provides key distribution (setting the values of zero "0" and one "1" bits in the binary number system) according to a protocol with four phase states in the rectangular and diagonal bases. A module for controlling the encoding of the in-phase and quadrature components of a radio signal at a subcarrier frequency is proposed. The use of quadrature phase shift keying (QPSK) provides noise immunity to external influences at high data transfer rates
-
CIRCUIT DESIGN METHOD FOR IMPROVING LARGE-SIGNAL SPEED OF CLASSICAL OUTPUT STAGES OF OPERATIONAL AMPLIFIERS USING BJT (CMOS, JFET OR SIGE) TRANSISTORS
А.А. Zhuk , А.I. Gavlitskiy , N.N. Prokopenko265-2772026-07-07Abstract ▼A significant drawback of classical output stages of microelectronic operational amplifiers, which today are implemented based on BJTs (bipolar junction transistors), CMOS (complementary metal-oxide-semiconductor transistors), or JFETs (junction field-effect transistors), including when these technologies are used together, is that they exhibit a relatively low output voltage slew rate under the influence of large-amplitude pulsed input signals. This undesirable effect is mainly caused by the presence of parasitic capacitances inherent in the reference current source circuits employed and in their output transistors. This paper discusses an original and effective circuit design technique that provides forced recharging of parasitic capacitances, which is used in output stages implemented in numerous patents of the world’s leading microelectronic companies. The introduction of a special differentiating transient correction circuit into the original schematics, as well as various options for its practical implementation, are considered for the first time. The circuitry of such output stages is protected by a patent of the Russian Federation. Four different modifications of buffer amplifiers have been developed and investigated, which are intended for use in modern technological processes implemented with silicon BJT or CMOS transistors, as well as with gallium arsenide n-JFET and p-n-p bipolar transistors. Examples of computer simulation of DC operating modes, as well as transient processes, are presented, which clearly demonstrate a significant increase in the maximum output voltage slew rate (by more than one to three orders of magnitude). The proposed advanced circuit solutions for GaAs transistors are recommended for practical application in microelectronic devices designed for operation under elevated temperature conditions.
-
IMPROVING REAL PERFORMANCE OF RCS WHEN SOLVING DIGITAL IMAGE PROCESSING TASKS USING FAST FOURIER TRANSFORM
A.V. Chkan2021-02-25Abstract ▼The article discusses the issues of digital processing of images of large dimensions in real
time using reconfigurable computer systems (RCS) on the base of programmable logic arrays
(FPGAs). RCS belongs to the class of high-performance multiprocessor computing systems that
have a programmable architecture that allows configuring the structure of a computer system and
optimally adjusting it to the algorithms of the solved task. At the same time, optimization of the
computational structure of the task reduced to the development and implementation of parallel
algorithms corresponding to the specifics of the RCS architecture used. All this allows to effectively
using RCS to solve a wide class of digital signal processing tasks. Offered are methods of increasing
specific and real performance of RCS when solving digital image processing problems
using fast Fourier transform (FFT). Using the example of a procedure for filtering images in the
frequency domain, the main computational steps and methods for optimizing them based on the
properties of the FFT algorithm are discussed. The use of optimization allows to significantly reducing
both the amount of computation and the amount of hardware resources of the FPGA andincrease the performance of RCS for image processing tasks. The FPGA resources freed because
of the optimization of the computational structure can be uses to further parallelize calculations
and accelerate the processing of incoming data. The advantages of presenting data in fixed-point
format when performing calculations on RCS are showed. The use of a fixed point allows not only
to increase the specific and real performance of a computer system compared to a floating point
due to the properties of the format, but also to use arbitrary data bit capacity, which is relevant for
most digital signal processing tasks. The solution to the problem of overflow of the bit grid when
using the fixed-point format using data bit scaling is discussed.
1 - 22 of 22 items
