Browsing by Author "Yevhraphov, Dmytro"

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    SDR-ТЕХНОЛОГІЇ ПРИХОВАНИХ ЛІНІЙ РАДІОЗВ'ЯЗКУ. SDR-THECHNOLOGIES OF ÑOVERT RADIO LINES
    (2019) Євграфов, Дмитро Вікторович; Yevhraphov, Dmytro
    The possibilities of Software Defined Radio (SDR) – technologies in the correlation processing of linear-frequency modulated (LFM) signals are examined. The structure of the correlation receiver of maximum likelihood is justified using modern SDR technologies. Since the signal arrival time is unknown after analog-to-digital conversion (ADC), the signals are fed to the correlation processing channels and to the maximum selection device, the signals from which are sent to the decision-making device. The decision maker evaluates the message that is transmitted if the signals exceed a certain detection threshold. The influence of the amplitude quantization of the signal on the detection process is analyzed, since with insufficient ADC bit depth, the signal is simply lost in the quantization noise. It is shown that the existing ADC bits allow processing signals with large bases, which makes it possible to use SDR technologies to create correlation receivers of chirp signals. The synthesis results are illustrated by simulations in the software environment Mathcad and Excel. For comparison, the simulation results are presented at the output of a conventional digital receiver, with a bandwidth that is equal to the band of the chirp signal. It is shown that to solve the analysis problem in the future, it is necessary to use the apparatus of two-component Markov processes, which allows one to find the distribution of the absolute maxima of random processes and sequences obtained by their discretization.
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    СИНТЕЗ АСИМПТОТИЧНО ОПТИМАЛЬНОГО ДЕТЕКТОРА ШУМОПОДІБНИХ СИГНАЛІВ. SYNTHESIS OF ASYMPTOTICALLY OPTIMIZING NOISE SIGNAL DETECTOR
    (2019) Євграфов, Дмитро Вікторович; Yevhraphov, Dmytro; Заїчко, Костянтин Вікторович; Zaichko, Kostiantyn; Білогуров, Володимир Андрійович; Bilohurov, Volodymyr; Назарок, Дмитро Станісловович; Nazarok, Dmytro
    The structure of a special technical tool for detecting noise-like signals, whose intensity varies according to the certain rule, is substantiated. The tool consists of a radio envelope processing device. It is shown, that the main one is a signal processing in the post-detector paths. A joint algorithm for detecting and evaluating a parameter for changing the intensity of a noise signal under a priori uncertainty regarding the radiation power and a parameter for changing the intensity is synthesized. During the synthesis, the uncertainty with respect to the power of the noise signal at the input of the receiver is first overcome, and then with respect to the parameter for changing the noise intensity. The synthesized post-detector algorithm for processing noise-like signals is optimal, when the ratio of the noise signal power to the receiver internal noise power at the output of the linear system tends to infinity. The post-detector detection path consists of a quadratic detector, a centering device, correlation processing channels, a maximum selection device and a threshold device. The maximum amplitude signal at the output of the maximum selection device is compared with the detection threshold. When the threshold is exceeded, an alarm is generated, and an informative parameter for changing the noise intensity is estimated by the number of the correlation channel with the maximum amplitude. The parameters of digital post-detector signal processing are analyzed and a conclusion is made about the possibility of implementing a processing algorithm on microprocessor systems.