2020 Moscow Workshop on Electronic and Networking Technologies (MWENT)
The work is devoted to the mathematical models study for operational failure rate estimating of traveling wave tubes. The detailed analysis of the parameters taken into account in the considered models is carried out. The key factors that have the greatest impact on the reliability characteristics are highlighted. Based on the results of numerical evaluation of the traveling wave tubes operational failure rate according to the considered mathematical models, a significant difference in the obtained results is shown. Mathematical models of operational failure rate, taking into account the key factors (temperature and manufacturing technology) based on the analysis of the causes of failure of traveling wave tubes are recommended to use. However, the considered mathematical models, in aggregate, do not take into account the key factors. This leads to an unreliable assessment of the reliability characteristics at the design stages
LoRa wireless network has become a widely spread technology among IoT systems recently. LoRa allows to use various ISM bands such as 433 MHz, 868 MHz and 915 MHz. During this study 433 MHz and 868 MHz frequencies have been compared. Parameters such as SNR and RSSI were measured at different floors and visualized. A comparative table of packet delivery ratio at various spreading factors can be found in this paper. A series of range experiments at different spreading factors showed that 433 MHz LoRa module gains a stronger signal. However, 868 MHz LoRa module shows higher percentage of received packets. It has been concluded that for nine-story building with concrete floors it is better to deploy 868 MHz LoRa network at 10th spreading factor.
The paper presents a solution to the question of increasing authenticity and accuracy in predicting dependability, in particular, the reliability of electronic equipment (EE) by simulation modeling. A review and analysis of existing solutions is carried out and their drawbacks are identified. The description of the developed FPGA based VI-module is given, which allows to assess the EE reliability characteristics with an accuracy of 18 decimal places. Also, the developed VI-module is highly reliable due to the use of a random number generator with a repetition period depending on the type of FPGA up to 2^(64-1) in the form of hardware/software implementation based on FPGA.
In this paper, we do an early study of circuit parameter variation for temperature-resistant SOI CMOS production technology on the examples of several standard circuit fragments. Circuits electrical characteristics are simulated at several values of temperature (in the range +27…+300 °C) and with account for MOSFET parameter mismatch figures derived from measurement data. The method involving a library of corner models provides a reasonable estimate of circuits behavior scatter due to the simultaneous influence of very high temperature and production process variability.
A DHA FH OFDMA that uses order statistics- based techniques can be a very promising technique for mMTC systems. However for any case of practical interest the transmission rate of a classical DHA FH OFDMA system is relatively low due to complexity restrictions. To solve this problem a solution using concatenated coding in multiple disjoint subbands has been proposed recently. In this paper another solution based on muti-tone multi-code transmission in a single subband is advocated. It is demonstrated that the proposed solution outperforms the single-tone DHA FH OFDMA using the same detector in terms of both complexity and performance and has lower complexity and latency and almost the same performance than the previously proposed multi-tone coded modulation scheme.
In this work, we would like to suggest the algorithm of technical specification on thermal modeling of on-board electronic systems. It solves the problem of gaining the projected working accuracy in high heat load including internal heat release on electronic components of on-board radio electronic systems. That is a problem which is often faced by radio-electronic’ designers. We focus on thermal modeling in “ASONIKA” space. As an example of circuit board, we use laser gyroscope. As a result, developed by us methods of ensuring high reliability can be used not only in the development of a laser gyroscope, but also for vast variety of radio electronic devices. The main purpose of this project is to get system approach and improve reliability. The method is applicable not only for Zeeman laser gyroscope but also for vast variety of optoelectronic devices. Implementation of this method in optoelectronic devices’ design allows us to get system approach and improve reliability and working accuracy in various heat ranges.
The authors propose a methods for providing thermal operation modes of on-board navigation devices. The methods allow to solve one of the problems that developers of on-board navigation systems are faced with – to ensure the specified accuracy of operation at high heat loads, including internal heat generation on the electronic components of printed circuit assemblies. The authors propose adding, at the initial stages of preparation for the simulation, permissible control for random variations in the parameters of electronic components. This approach is a significant difference from the standard procedure for modeling thermal conditions. The ability to take into account random variations in the parameters of electronic components becomes possible if there is a formed base of structural elements. The application of the developed methods in the design of electronic on-board navigation devices allows a systematic approach to development and to increase the reliability and accuracy of devices to the technical task required level.
The authors propose to provide for the use of digital counterparts of physical processes in the electronic equipment of cyber-physical systems in their design for a long duration of active existence, for example, spacecraft in orbit or in a long flight. At the same time, it is proposed to create a database of big data in which synthesized digital counterparts are stored in the on-board computers of cyber-physical systems. They are designed to monitor sensor readings of electrical, thermal, mechanical and other physical processes of space equipment. The algorithm of functioning of the proposed structure of the cyber-physical system is constructed. The paper experimentally confirms the need to take into account the mutual influence of heterogeneous physical processes of the space cyber-physical system when creating digital counterparts for it.
A model of a composite consisting of a dielectric base with a small admixture of semiconductor nanoparticles shaped as identical ellipsoids of revolution is considered. A uniform spatial distribution of the impurity and a uniform distribution of the directivity of the axes of revolution are assumed.
It is shown that the formulas obtained for the effective dielectric constant of the composite correspond to a superposition of two Debye processes with different relaxation times. The dielectric constant strongly nonlinearly depends on the ratio of semi-axes of the ellipsoids of revolution. This feature allows one to obtain good agreement with experimental data under the assumption that the aggregation of nanoparticles is possible even at low concentrations.
The model implies that, in the absence of an increase in the aggregation of conducting nanoparticles with an increase in the concentration, the dielectric constant of the composite linearly depends on the impurity concentration. For a composite with growing aggregation of nanoparticles, this dependence exhibits a nonlinear growth.