Search results for "TW"
showing 10 items of 16860 documents
Optimum Design and Performance of an Electron Gun for a Ka-Band TWT
2019
This paper deals with optimum design and development of a thermionic electron gun to meet specified beam requirements within defined electric and geometric constraints for a Ka -band traveling wave tube (TWT) for space applications. The electron gun design is based on the Pierce method and carried out according to the iterative process indicated by Vaughan. The design of a periodic permanent magnet (PPM) beam focusing system for the stability of the beam is also required. A sensitivity analysis, by varying electric parameters and geometric parameters, is presented and taken into account as a fundamental role to the aim of optimizing the design of the Pierce gun. A cathode current value of 5…
Design and analysis of non-linear circuit with tunnel diode for hybrid control systems
2018
Electric circuits with tunnel diode's represent a classical example of dynamic systems with nonlinearities, which feature piecewise negative damping and multiple equilibria and, as consequence, nontrivial trajectories in the state-space. In this paper, we describe the experimental design and analysis of an electrical circuit, including a tunnel diode, allowing for a storage behavior with bistable output voltage states - low and high. The system is modeled for simulation and an experimental setup is designed and implemented in order to run a formal verification on different tools, applying a variety of hybrid control methods. The nonlinear diode's characteristic curve is experimentally deter…
Measurements on partial discharge in on‐site operating power transformer: a case study
2018
This study presents the case study of a substation in-service power transformer referred to the on-site partial discharge (PD) detection and evaluation methods. An original methodology for simultaneous application of three methods is proposed: electrical, acoustic and ultra-high frequency. Transformer is powered by the power grid and no external generator is required according to the proposed methodology. Furthermore, several possibilities of applying these concurrent measurements and benefits of such solution in terms of result interpretation, interference resistance and on-site measurement applicability are indicated. The proposed methodology allows for a fast, accurate and secure PD diag…
Custom measurement system for memristor characterisation
2021
Abstract A cheap, compact and customisable characterisation system for memristor devices, working between ± 10 V, is presented. SPICE (Simulation Program with Integrated Circuit Emphasis) simulations are performed to verify the circuit feasibility and a proper software is developed to drive the system. The potentiality of the realised system is tested by performing several electrical measurements on both Cu/HfO2/Pt memristors and two-terminals commercial devices.
Pulsed Electro-Acoustic Method for specimens and cables employed in HVDC systems: Some feasibility considerations
2018
Recent experiments on the use of the PEA method for testing dielectric materials in specimens and comparison with a detailed model provide an insight of the phenomenon and suggest the need of adopting similar models also for cables. What is said is even more important considering the possible future adoption of the PEA methodology to test DC cables for Pre-Qualification and Type Tests. The use of an accurate model of the PEA cell used for testing specimens and related experiments prove that the thickness of the different parts composing the PEA setup is a basic element for providing accurate charge reading and interpretation of the phenomenon. Both simulation and experimental results, carri…
Flexible and efficient computer-aided design tool for advanced comb-line rectangular waveguide filters
2015
A very flexible and efficient computer-aided design CAD tool, specifically suited for advanced comb-line rectangular waveguide filters, is presented in this work. The developed software tool, which makes use of a full-wave analysis technique based on the Boundary Integral-Resonant Mode Expansion method, allows loading the considered comb-line resonators with any number of radially symmetrical partial-height metallic posts. The implemented CAD tool also allows dealing with coupling windows of arbitrary cross-section, thus drastically enhancing the flexibility of the CAD process. The excitation of the analyzed components, which is performed using generalized coaxial probes, has also been inte…
Enabling partially reconfigurable IP cores parameterisation and integration using MARTE and IP-XACT
2012
International audience; This paper presents a framework which facilitates the parameterization and integration of IP cores into partially reconfigurable SoC platforms, departing from a high-level of abstraction. The approach is based in a Model-Driven Engineering (MDE) methodology, which exploits two widely used standards for Systems-on-Chip specification, MARTE and IP-XACT. The presented work deals with the deployment level of the MDE approach, in which the abstract components of the platform are first linked to the lower level IP-XACT counterparts. At this phase, information for parameterization and integration is readily available, and a synthesizable model can be obtained from the gener…
Multi-application Based Fault-Tolerant Network-on-Chip Design for Mesh Topology Using Reconfigurable Architecture
2019
In this paper, we propose a two-step fault-tolerant approach to address the faults occurred in cores. In the first stage, a Particle Swarm Optimization (PSO) based approach has been proposed for the fault-tolerant mapping of multiple applications on to the mesh based reconfigurable architecture by introducing spare cores and a heuristic has been proposed for the reconfiguration in the second stage. The proposed approach has been experimented by taking several benchmark applications into consideration. Communication cost comparisons have been carried out by taking the failed cores as user input and the experimental results show that our approach could get improvements in terms of communicati…
C-switches: Increasing switch radix with current integration scale
2011
In large switch-based interconnection networks, increasing the switch radix results in a decrease in the total number of network components, and consequently the overall cost of the network can be significantly reduced. Moreover, high-radix switches are an attractive option to improve the network performance in terms of latency, since hop count is also reduced. However, there are some problems related to the integration scale to design such single-chip switches. In this paper we discuss key issues and evaluate an interesting alternative for building high-radix switches going beyond the integration scale bounds. The idea basically consists in combining several current smaller single-chip swi…
Magneto-optical properties of two-layer film systems based on Fe and Cr
2020
The results of the investigation of two-layer Fe/Cr systems using the magneto-optical Kerr effect (MOKE) are presented in this paper. The samples were obtained by thermal evaporation in a vacuum with a thickness of individual layers from 2 nm to 50 nm. It was found that the presence of the Cr layer significantly affects the values of the coercivity and the Kerr angle. At a substrate temperature of 450 K, the value of the coercivity is almost half that of the same sample obtained at room temperature of the substrate. In addition, the influence of the order of deposition of layers, as well as the effect of a thin gold protective layer on the parameters measured by the Kerr method, is shown. …