кандидат технических наук (2009), доцент
кафедра автоматики и процессов управления
Автор более 50 научных работ. Сфера научных интересов - цифровая обработка сигналов; радиоэлектроника.
Ph.D. in Engineering (2009), Associate Professor of the Department of Automation and Control Processes
The author of more than 50 scientific publications. Area of expertise: digital signal processing; radio electronics.
магистр техники и технологии по направлению "Управление в технических системах" (2015), аспирант
кафедра автоматики и процессов управления
Автор более 10 научных работ. Сфера научных интересов - информационные и телекоммуникационные системы; цифровая связь; цифровая обработка сигналов.
Master's Degree in Engineering and Technology in Engineering System Management (2015), postgraduate student of the Department of Automation and Control Processes
The author of more than 10 scientific publications. Area of expertise: information and telecommunication systems; digital communication; digital signal processing.
кандидат технических наук (1974), доцент (1980)
кафедра автоматики и процессов управления
Автор более 30 научных работ. Сфера научных интересов - математическая теория систем; цифровая обработка сигналов.
Ph.D. in Engineering (1974), Associate Professor (1980) of the Department of Automation and Control Processes
The author of more than 30 scientific publications. Area of expertise: mathematical system theory; digital signal processing.
кандидат технических наук (2013), доцент
кафедра математического обеспечения и применения ЭВМ
Автор более 50 научных работ. Сфера научных интересов - цифровая обработка сигналов; вейвлет-анализ; спектральный анализ; моделирование в MATLAB.
Ph.D. in Engineering (2013), Associate Professor of the Department of Software and Computer Application
The author of more than 50 scientific publications. Area of expertise: wavelet-analysis; spectral analysis; MATLAB modeling.
кандидат технических наук (2014) , доцент
кафедра радиотехнических систем
Автор более 20 научных работ. Сфера научных интересов - теория сигналов; статистические методы обработки радиотехнических сигналов; дистанционное зондирования водной и земной поверхностей; рассеяние радиоволн шероховатыми поверхностями; математическое моделирование радиолокационных систем.
Ph.D. in Engineering (2014), Associate Professor of the Department of Radio Equipment Systems
The author of 20 scientific publications. Area of expertise: signal theory, statistical signal processing methods, remote sensing of water and earth surface, scattering of radio waves by rough surfaces, mathematical simulation of radar systems.
кандидат технических наук (2012), доцент
кафедра систем автоматизированного проектирования
Автор более 70 научных работ. Сфера научных интересов - математическое, программное и методическое обеспечение встраиваемых САПР и киберфизических систем, включая аппаратно-ориентированные методы численного интегрирования; алгоритмы встраиваемых систем управления и обработки сигналов; нелинейная динамика в технических системах; параллельные и распреде ленные вычисления; архитектура аппаратных генераторов хаотических сигналов.
Ph.D. in Engineering (2012), Associate Professor of the Department of Computer-Aided Design
The author of 70 scientific publications. Area of expertise: mathematical models; applied and computational mathematics; numerical methods; nonlinear dynamics; numerical modelling; finite-difference schemes; recurrence analysis; bifurcation analysis; ODE solvers; computeraided design; chaos theory; scientific computation; cloud computing; parallel algorithms; embedded systems; data acquisition and processing.
кандидат технических наук (2000), доцент (2001), начальник отдела
Автор 68 научных работ. Сфера научных интересов - информационные и телекоммуникационные системы; цифровая связь.
Ph.D. in Engineering (2000), Associate Professor (2001). Head of the Department
The author of more than 50 scientific publications. Area of expertise: information and telecommunication systems; digital communication.
доктор технических наук (2009), доцент (2010), начальник отдела
Автор 139 научных работ. Сфера научных интересов - информационные и телекоммуникационные системы; цифровая связь.
D.Sc. in Engineering (2009), Associate Professor (2010), Head of Department
The author of 139 scientific publications. Area of expertise: information and telecommunication systems; digital communication.
Представлены разработка и исследования различных методов демодуляции частотно-манипулированных сообщений в режиме псевдослучайной перестройки рабочей частоты при заданном диапазоне изменения отношения "сигнал/шум" (ОСШ). Разработанные методы основаны на использовании спек трального и корреляционного анализа. На основе разработанной в MATLAB/Simulink модели канала связи вычислена ошибка исследуемых методов демодуляции при различных значениях ОСШ. В результате исследования определен наилучший метод демодуляции при заданном ОСШ.
Demodulation task is encountered in many practical applications including digital signal processing and digital communications. Demodulation is connected with the communication system performance. Demodulation depends on a number of factors including signal-to-noise ratio (SNR) in the received message. In practice, it is necessary to minimize the number of errors for the given SNR and therefore new demodulation techniques are constantly developed with increased interference immunity. Demodulators aimed at for frequency-hopping spread spectrum signals have to meet special requirements since the message length can reach several ms and the number of messages can exceed several dozens.
Frequency-hopping spread spectrum is a technique of information transmission via radio channel and it is distinguished by variable carrier frequency that can change many times. The carrier frequency changes according to a pseudo random number sequence, which is available to both a sender and a recipient. This technique improves interference immunity of a communication channel.
Frequency-hopping spread spectrum is used in civil and special applications. This signal is stable to jamming (until the third side finds out the number sequence), which makes it possible to use it for special purposes (however, the signal still needs additional encryption).
Demodulation includes signal detection, synchronization, message type determination (modulation speed and modulation type), decoding, determination of autostarting and autostop combinations (for message identification), composition of the received message. The paper considers the tasks beginning with message type determination.
Message type determination can be carried out several ways: using the cross-correlation function, spectral analysis, etc. Since the structure of a synchrosequence is known, it is possible to obtain more precise results using the crosscorrelation function. Several synchrosequences are formed for each message and then we compute their cross-correlation with the received message. The analysis includes the comparison all the results of cross-correlation function computa-tion and finally we make a decision regarding the message.
Determination of autostarting and autostop combinations is performed by comparing autostarting and autostop combinations from the database. Each autostarting combination determines the receiver operation mode (single-channel or frequency-hopping spread spectrum). Determination of combinations is performed during signal demodulation.
Reception of a frequency-hopping spread spectrum signal is performed according to the frequency plan. According to this plan, the carrier frequency changes in fixed time points. After receiving the autostarting combination of frequencyhopping spread spectrum, a reception mode for frequency-hopping spread spectrum signal is switched on. After receiving the autostop combination this mode is terminated. The output of a demodulator is the message itself, modulation type, and carrier frequency.
The outcome of demodulator performance can be represented with a table. The first column of this table contains the carrier frequency, the second column contains frequency deviation, the third column - modulation type, the fourth one - message speed, the fifth one and further - the message itself.
In the paper, we provide new demodulation techniques of frequency-modulated messages for the given SNR. The developed techniques are based on spectral analysis and correlation analysis. We determine the computational complexity of the developed demodulation techniques. The total error is computed for each SNR and the selected demodulation technique using the developed MATLAB/Simulink model for a communication channel. Finally, we conclude about the best demodulation technique for the selected message type for the given SNR.
The authors declare that there are no conflicts of interest present.