2024

Постійне посилання на фонд

https://ela.kpi.ua/handle/123456789/66700

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Перегляд 2024 за Автор "Hryzo, A. A."

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  • Ескіз
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    Implementation of Method of Minimizing the Side Lobe Level of Autocorrelation Functions of Signals With Nonlinear Frequency Modulation
    (КПІ ім. Ігоря Сікорського, 2024) Kostyria, O. O.; Hryzo, A. A.; Khizhnyak, I. A.; Fedorov, A. V.; Lukianchykov, A. A.
    An important problem that is solved during the creation of new and modernization of existing radar equipment is to ensure the maximum range of detection of air targets, which requires increasing the radiated power while maintaining the required range resolution. Since the generating devices, which are now widely used as semiconductor elements, have limited peak power, the required energy is emitted by increasing the duration of the sensing radio pulse, and the requirements for resolution are met by using so-called complex signals, the product of the spectrum width of which and their duration (signal base) is greater than one. One of the types of complex signals is multifragment signals with nonlinear frequency modulation, which, unlike the well-known linear frequency modulated signals, have a significantly lower peak side lobes level of autocorrelation functions, but the value of this level depends significantly on the frequency and time parameters of the signal. Finding parameters that minimize the side lobes level of the autocorrelation function of nonlinear frequency modulated signals, which include fragments with linear frequency modulation, is an important scientific and technical problem, the solution of which is the subject of this article. The peculiarity of considering this issue is that, in contrast to the previously proposed implementation of the method of minimizing the side lobes level for mathematical models with a current time change, the paper develops models of shifted time, that is, when the time count of each subsequent signal fragment is shifted to zero. The first section of the paper analyzes the known publications, which shows that the method of minimizing the side lobes level of correlation functions has not been considered before for mathematical models of the shifted. Given this circumstance, the second section of the paper formulates the research objectives. The theoretical justification of a new variant of the proposed method by developing mathematical time-shifted models for two- and three-fragment nonlinear frequency-modulated signals, as well as the modeling results, are presented in Section 3. In further research, it is planned to develop an algorithm for optimizing the time-frequency parameters of signals with nonlinear frequency modulation based on mathematical models of current and shifted time.
  • Ескіз
    ДокументВідкритий доступ
    Mathematical Model of Shifted Time of Combined Signal as Part of Fragments with Linear and Quadratic Frequency Modulation
    (КПІ ім. Ігоря Сікорського, 2024) Kostyria, O. O.; Hryzo, A. A.; Solomonenko, Yu. S.; Dodukh, O. M.; Biernik, Ye. V.
    The issues of synthesis of nonlinear-frequency modulated probing signals, which, in comparison with wellknown linear-frequency modulated signals, have a lower maximum level of side lobes of the autocorrelation function, have a practical orientation, relate to actual problems of theory and practice of forming signals with intra-pulse modulation for radio electronic means for various purposes. The paper considers a combined nonlinear-frequency modulated signal consisting of linearly and quadratically-frequency modulated fragments. The peculiarity of the proposed approach to the description of its mathematical model is the introduction of frequency-phase compensation components, which reduces the maximum level of the side lobes of the autocorrelation function of the signal. Calculation of values of compensation components is based on consideration of the effect of derivatives of function of instantaneous phase of fragments up to the most significant order inclusive. The limitation of the method should include the requirement for the existence of their final quantity. In the first section of the article, an analysis of known studies and publications is carried out, which states that for the mathematical model of shifted time, considered in the work, the proposed method of compensating for frequency-phase distortions has not been previously considered. Therefore, in the second section of the work, the corresponding task of the study is formulated. In order to achieve the formulated task of research, the third section of the work develops a mathematical model of the shifted time of the combined signal, which contains the compensatory components of the specified distortions. The importance of their consideration in the resulting signal is theoretically substantiated and clearly demonstrated. As a result of the research, the theory of synthesis of combined signals has been developed, the composition and determination of the magnitude of frequency-phase distortions, which are caused by the appearance of the third derivative of the instantaneous phase function of the quadraticallyfrequency modulated fragment, have been established. As a direction for further research, it is planned to develop and study a mathematical model of shifted time of a three-fragment combined signal with a quadratically-frequency modulated fragment.