Radiophysical System Research Articles

Нелинейная фильтрация хаотического сигнала при наличии шумов

The creation of radio engineering systems based on the effects of stochastic and chaotic dynamic is a promising direction. The task of developing such systems must be oriented toward using the results of theoretical studies of processes in nonlinear radiophysical systems. The subject of this study is the nonlinear filtering of a mixture of chaotic oscillations and noise based on the stochastic resonance effect occurring in a bistable system with the aim of isolating the information chaotic signal. Usually, noise is considered to be “white”, and the signal is narrow-banded. As a bistable system, a Schmitt trigger can be used. For narrowband signals, the stochastic resonance effect has been studied in sufficient detail theoretically, for broadband information signals, applied research is insufficient. The stochastic resonance effect is a phenomenon in which the response of a nonlinear system to a weak external signal amplifies with increasing noise intensity to some optimal value. In the study of radio engineering systems, chaotic oscillations can be used as information systems. Theoretical basis for research of information processing systems in radio engineering systems using chaotic signals is research in the field of nonlinear radiophysics. Of particular importance in this case is the selection of solutions at the model level, in particular, based on the results of circuit simulation of practically realized devices on the existing element base.

Ионно-молекулярная модель памяти. Причины, приводящие к искажению информации, хранящейся в памяти

. As in perception, transmission, processing and storage of information in technical systems, distortion (useful) information in the functioning of memory is real and ontologically grounded. The reason of the distortion is the theme of this article from the cycle of works on creation of ion-molecular memory model. By analogy with radio-physical systems – nature is "stingy" on the system moves - the principle of evolutionary conservatism (by I.G. Gerasimov and A. A. Yashin) – the main reason of distortion is an information noise. Classification of information noise in the functioning of memory is developed. The cellular level of noisiness is highlighted. It is shown that an important reason for the distortion of information is a copy of information that is essential for brain function. The repair mechanisms distorted information by modifying the parameters of the spectrum of activity of hydrogen ions are considered. It is important to visualize: informational noise depends on the quality of the information signal, and on the quality of (generalized) receiver of useful information that we observe in the memory structure of the bio-object, in human – in the first place. The evolutionary principle of conservatism, the essence of the system-wide law of the universe, according to which the nature is «stingy» in terms of variety of moves and is based on the famous Poincare hypothesis, now – on the Poincare-Perelman theorem. According to this principle, there is a perfect analogy in the implementation of living and non-living systems, including technical solutions created by man. The prerogative of the cellular level of degradation is even more very obvious: in any system, its qualitative characteristics are determined by the degree of perfection / imperfection of its constituent elements-"primary sources".

Review of the Book “Non-Traditional Dynamics:Theory and Practice”

The offered book is devoted to theoretical and applied problems of nonlinear dynamics of radio physical systems. The main goal of this book is theoretical and experimental investigations of key principles and laws of ra- dio physical system’s functioning with continuous and discrete time, in which both regular and chaotic oscillation types may occur.

Book Review of Non-Traditional Dynamics in Electronics: Theory and Practice

The new book published by Scientific Research Publishers, USA in 2011 is devoted to investigation of properties of dynamic radio physical systems and to development of methodic fundamentals for creation the chaotic oscillation sources and forecasting of nonlinear dynamic system behavior at variation of its parameters. The urgency of such investigation execution in this direction is determined both by the necessity of new ideas development in understanding of nonlinear dynamics of various processes independently upon its affiliation with the specific physics area and by need of the modern radio physics and radio electronics in sources of wide-band chaotic oscillations and signals. This book makes a considerable contribution in this area because it contains theoretical, modeling and experimental results of the analysis of bifurcation phenomena and processes in chaotic systems as well as issues of information transmission using chaotic signals. In this book for the first time the auto-parametric scenario of stochastization is described, conditions are formulated, at which movements in arbitrary dynamic systems are governed by the unified system of spectral-time equations. Phenomena of synchronization of chaotic movements and the intermit synchronization are discovered and investigated in detail. The bifurcation sense of the control parameter of modified logistic map is revealed, which ensures reproduction of strictly chaotic temporal sequences. The aggregate of this book’s results may be classified as the new large scientific achievement. Authenticity of results obtained is determined by its consistent (became classical) laws of dynamic system functioning and coincidence of numerical and physical experiments at testing of offered mathematical models of dynamic systems, and successful functioning of the described radio electronic devices. This book contains preface and six chapters. To my opinion, all materials are reliable and to the right degree are supported by necessary theoretical and experimental substantiation. Authors on the basis of numerical and physical experiments prove earnestly the opportunity of existence of the strange non-chaotic attractor in nonautonomous radio electronic circuits at single-frequency sinusoidal influence and on the basis of result generalization of much number of numerical and physical experiments authors offer and substantiate the feasibility for the wide class oscillator and relaxation generation system of the specific stochastization scenario, which did not meet earlier in the scientific publications on nonlinear dynamics. Theoretical analysis of modified logistic maps (MLM) and appropriate numerical and physical experiments allows authors to discover and investigate conditions of arising of the unknown phenomenon—intermittent synchronization. At last, some results of the book are checked by the functioning radio electronic devices. Scientific and practical importance of investigations

Estimating delay from a dynamical system response to a weak pulsed action

A new method is proposed for estimating the delay time of a delayed-feedback system, which is based on an analysis of the system response to a weak external perturbation in the form of rectangular pulses. The method is applicable to systems that perform both periodic and chaotic oscillations. The efficiency of the proposed procedure is demonstrated based on numerical examples and for the experimental time series of a real radiophysical system.

Radiophysical System for Examining Functional State of a Patient’s Brain

The radiophysical system МRТRS for functional study of the brain with one multichannel microwave radiothermograph measuring the intrinsic electromagnetic radiation of brain tissue within a range of frequencies from 650 to 850 MHz is considered. The structure and basic characteristics of the system are described. It is shown that the insertion into this structure of additional measuring channels for detection of the signals defined by autonomous regulation of heart and changes in neurohumoral processes in the cardiovascular system raises information value of the study. A new software system of secondary signal processing was developed. This software is applied to spectral analysis by means of modified basic Morlet wavelets, which detects time and frequency heterogeneity of studied processes.

Admittances characterizing a partially filled rectangular waveguide with holes in its side face

Admittances characterizing a partially filled rectangular waveguide with holes in its side face have been determined. Sections of such waveguides are elements of complex waveguide connections that are used to construct microwave digital telecommunications circuits built on rectangular waveguides partially filled with dielectric. Such admittances include transformation ratios that were determined in this study by two different techniques: by way of expanding the Mathieu functions into a series in terms of trigonometric functions and by way of expanding the Mathieu functions into a series in terms of Bessel functions. The results obtained in this study can be used in calculations of six-pole and eight-pole networks and can form the basis for engineering design of microwave channels built on such waveguides and designed for different radiophysical systems.

Invariant Transformation in Identification Theory

A generalized approach to tackling the problems on identifying the condition of natural media and objects by means of invariant models is discussed. Ways and techniques for synthesizing models using the tensor analysis are examined. A physical object along with the observation system is presented. In this study a procedure for optimizing multiposition radiophysical systems meant for the retrieval of data on natural media and objects is suggested. This method is based on equivalent transformations of a topological graph. The linear or nonlinear case is considered, and owing to a series of successive transformations of initial-space coordinates it has become possible to arrive at the configuration of a model, which offers minimal losses as decision are made about a specific object.

Special approaches to global reconstruction of equations from time series

Some problems arising during global reconstruction from time series are illustrated by reconstruction of efalon equations and modeling оf real-world radiophysical systems. Efficiency оf specialized approaches oriented to modeling оf restricted classes of systems is demonstrated and new specific techniques are proposed.

Reconstruction of scalar time-delay system models

A new method is proposed for the reconstruction of scalar time-delay system models. The method is simple, fast, and applicable to the analysis of noisy data. The performance of the proposed method is illustrated by application to the time series obtained in a numerical experiment (with a possible noise component) and in a real radiophysical system.

Map «atlas» of dynamic modes for standard models of nonlinear dynamics and of radiophysic systems

One of the most effective computer methods of two-parametrical research of nonlinear systems is the construction of maps of dynamic modes. On maps the certain colours designate cycles of the various periods and areas of chaotic dynamics. The variety of noulinear model and radiophysical systems has required to create some kind of «atlas» of maps for most known of them. Most of basic classes of dynamic systems are submitted: one-dimensional irreversible maps, two-dimensional convertible maps, flows and nonauthonomous systems.

Large discrete nonlinear models of periodically driven RL-diode circuit

By experimental observables of natural and driven oscillations the point maps modeling complicated dynamics of periodically driven diode resonator are constructed and investigated. The place of the proposed maps among other mathematical models of this popular radiophysical system is discussed.

Markovian fluctuation-dissipation theory of open radiophysical systems

Markovian fluctuation-dissipation theory of open radiophysical systems

Phase transitions in nonequilibrium radiophysical systems

Phase transitions in nonequilibrium radiophysical systems