Измерение спектрально-энергетических характеристик контактных радиопомех типовых механических соединений и построение их эксплуатационных макромоделей
The scientific significance of the scientific results outlined in the work is to investigate the mechanisms of formation of contact radio interference that arise as a result of the electromagnetic field of radio transmitters located on aircrafts on current-carrying mechanical contacts of structures with nonlinear and time-varying resistances, as well as the formation of electromagnetic interference. The scientific results obtained as a result of the studies showed the mechanisms of formation of a flowing current caused by induced EMF, along the elements of the airplane structure, which lead to the formation of a radiation mechanism by these elements of the secondary electromagnetic field interacting with the primary irradiating electromagnetic field of the radio transmitter. By registering and analyzing the spectral composition of the electromagnetic radiation of mechanically connected elements of the ES structure, it is possible to control the quality of assembly of the structural elements. Carrying out complex diagnostics based on measuring the spectral composition of the whole product, having the measuring antennas around the product under investigation it is possible to conduct reliable estimates of the quality of assembly of both individual mechanical elements and the entire ES design as a whole. The studies carried out in the work can be put into the development and study of a contactless express method for assessing the quality of assembly and installation of structures. The method is based on the registration and analysis of artificially generated contact jamming under the influence of mechanical vibrations and a high-frequency harmonic electrical signal on the elements of aircraft structures forming a phase-amplitude-modulated oscillation circuit, which are recorded by a spectrum analyzer or a FAM receiver or AM oscillations. In this case, the levels of its spectral components are measured with a change in the frequency of mechanical influences in the range determined by the operating conditions. The measured level of the spectral components of the emitted amplitude-modulated oscillations is compared with the level of the spectral components of the signal emitted by the design of the reference block with given mechanical parameters and having a standardized level of contact interference. The main result of these studies allows us to use the considered in the field of electromagnetic compatibility (EMC) as an undesirable phenomenon, the formation of contact jammers has been used successfully to evaluate the mechanical properties of structures (assessing the quality of their assembly) of a wide variety of aircraft technical devices and devices, including the quality of assembly and installation related to the tightening torque of fasteners).
Hardware-software subsystem designed for MOSFETs characteristic measurement and SPICE model parameter extraction taking into account radiation effects is presented. Parts of the system are described. The macromodel approach is used to account for radiation effects in MOSFET modeling. Particularities of the account for radiation effects in MOSFETs within the measurement and model parameter extraction procedures are emphasized. Application of the subsystem is illustrated on the example of radiation hardened 0.25 μm SOI MOSFET test structures.
The basic model for calculating failure rates of mechanical elements, the example of a class of mechanical "spring". The results of the analysis of mathematical models. We consider the idea of using a macro model calculation of failure rates. As well as a comparative analysis of the calculations of the spring isolator all methods.
The paper presents an approach to the implementation of multiport linear dynamical blocks in a circuit simulator. Block characteristics are supposed to be presented in the form of rational transfer functions. The approach is based on the state space method, which allows avoiding problems of numerical convolution. The extension of the approach to the case of the exponential-rational form of transfer function is taken into account. The MNA formulation of Laplace element model is presented. The methodology providing construction of arbitrary multi-port Laplace elements on the base of developed set of simple Laplace elements is proposed. The approach was implemented in SPICE3 circuit simulator. Examples are given in the paper.
The paper presents a new approach to the construction of reduced linear system in the form of rational transfer functions. The approach is based on the minimization of approximation error defined by an integral criterion. The approach modification aimed at the model order minimization under the given error norm is also provided. The approach extension to the case of vector transfer functions is considered. The developed computational algorithm is based on the Gauss-Newton method. Testing examples presented in the paper confirm the method efficiency.
Generalized error-locating codes are discussed. An algorithm for calculation of the upper bound of the probability of erroneous decoding for known code parameters and the input error probability is given. Based on this algorithm, an algorithm for selection of the code parameters for a specified design and input and output error probabilities is constructed. The lower bound of the probability of erroneous decoding is given. Examples of the dependence of the probability of erroneous decoding on the input error probability are given and the behavior of the obtained curves is explained.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.