Monolithic mm-wave phase shifter using optically activated superconducting switches

A phase shifter is disclosed having a reference path and a delay path, light sources, and superconductive switches. Each of the superconductive switches is terminated in a virtual short circuit, which may be a radial stub. Switching between the reference path and delayed path is accomplished by illuminating the superconductive switches connected to the desired path, while not illuminating the superconductive switches connected to the other path

Microwave Components with MEMS Switches

RF MEMS switches with metal-metal contacts are being developed for microwave applications where broadband, high linearity performance is required. These switches provide less than 0.2 dB insertion loss through 40 GHz. This paper describes the integration of these switches into selected microwave components such as reconfigurable antenna elements, tunable filters, switched delay lines, and SPDT switches. Microwave and millimeter wave measured results from these circuits are presented

A VLSI implementation of the collision avoidance switch protocol for CAMB tree LANs

To solve a performance bottle neck in random access LANs due to packet collisions and their resolution, collision avoidance switches are introduced. These switches allow random access protocols to achieve high performance by resolving collisions among packets. A conventional hardware implementation of these switches is the use of TTL chips. In this implementation; a handful of TTL chips are required to forma single switch (e.g., 18 TTL chips are needed for an implementation of the CAMB switch [7]). Thus, implementation of a complete network, which requires several of these switches, could very well result in a large and complex hardware system.Today's modern chip technology allows us to pack large quantity of logic in a single chip. By transferring the conventional implementation of the collision avoidance switches into a VLSI chip, the complexity of the resultant hardware is greatly reduced, not to mention the improvement in hardware performance and ease of packaging.This report provides an overall study of the collision avoidance protocols for the tree LANs with emphasis on the implementation of collision avoidance switches. Hardware implementations of sorne of these switches are discussed. And a VLSI implementation of the CAMB switch protocol is introduced

Identificación y evaluación de vulnerabilidades de la Red Lan Capa 1 y 2, para el ejército Nacional de Colombia dependencia fortaleza ubicado en la ciudad de Bogotá

En este documento se evalúa y se analiza la topología de una red LAN compuesta por un número de dispositivos finales, switch, router y su cableado estructurado. Se busca verificar las condiciones actuales de esta red respecto a su estado, configuración, diseño y arquitectura. A partir del resultado, se expondrán las posibles transformaciones y mejoras que se pueden implementar en la red seleccionada para la investigación, ubicada en la unidad militar GRUPO FORTALEZA DEL EJERCITO NACIONAL.This document evaluates and analyzes the topology of a LAN network consisting of a number of end devices, switch, router and structured cabling. It seeks to verify the current conditions of this network regarding its status, configuration, design and architecture. From the result, the possible transformations and improvements that can be implemented in the network selected for the investigation, located in the military unit GRUPO FORTALEZA DEL NACIONAL ARMY, will be presented.Glosario. -- Resumen. -- Introducción. -- 1. Esquematización del tema. -- 1.1. Descripción y formulación del problema. -- 1.2. Justificación. -- 1.3. Objetivos. -- 1.3.1. Objetivo General. -- 1.3.2. Objetivos Específicos. -- 1.4. Alcances y limitaciones del proyecto. -- 1.4.1. Alcances. -- 1.4.2. Limitaciones. -- 2. Marco de referencia. -- 2.1. RED. -- 2.1.1. Red LAN. -- 2.1.2. Red WAN. -- 2.2. Switch. -- 2.3. Router. -- 2.4. Port Security. -- 3. Metodología. -- 3.1. Verificar. -- 3.2. Actuar. -- 3.3. Planear. -- 3.4. Hacer. -- 4. Condiciones actuales de la red ejército nacional dependencia fortaleza. -- 4.1. Extracción y obtención de la información de la red actual. -- 4.1.1. Ubicación de Equipos. -- 4.1.2. Condiciones Eléctricas. -- 4.2. Características del Router. -- 4.3. Características de los Switch. -- 4.4. Condiciones del cableado estructurado. -- 5. Análisis e identificación de vulnerabilidades. -- 5.1. Cableado estructurado. -- 5.2. Equipos intermedios. -- Conclusiones. -- Recomendaciones. -- Anexos. -- Webgrafia

The evolution of trilingual code-switching from infancy to school age: the shaping of trilingual competence through dynamic language dominance

This article reports on a study of the code-switches produced by two children who acquired their three languages in early childhood. We compared formal and functional aspects of their switches recorded at two different stages of their development. Of particular interest was the consideration of sociolinguistic variables that have intervened in the children’s environment. We undertook a quantitative and qualitative analysis of the children’s code-switches to ascertain the frequency of switching, the use of each of the three languages employed for switching and the linguistic complexity of the switches. We assumed that the sociolinguistic conditions that changed the linguistic landscape in which these children operated would be reflected not only in the development of each of their languages, but also in the kind of switches that they produced. We tried to establish whether it is the case that certain forms and functions of code-switches constitute a "core" of trilingual language behaviour while others are prone to change. Ultimately, our aim was to gain an insight into the specific trilingual language production processes over a given period of time that can shed light on the development and nature of trilingual competence

Start/stop switches for testing detonation velocity of explosives

Printed-circuit process produces ordnance-initiated start/stop switches. Method is faster and less costly than fabriction by hand, and produces switches of uniform quality

NbTi foil thermally controlled switches for superconducting converters with operation frequency up to 50 Hz. Part 1: Experiment

The increase of the operation frequency of superconducting converters up to 50 Hz opens new ways to improve their parameters. Thermally controlled switches using NbTi foil are able to operate at industrial frequency with reasonable efficiency and dynamic parameters. Such switches have been developed and tested. The paper presents experimental results of static and dynamic behavior of the switches. The rectification mode was tested with different shapes of the applied voltage, with currents from 150 to 450 A, voltages from 10 mV to 2.5 V and recovery times between 1 and 10 ms. The switches presented here have experimentally demonstrated superior dynamic parameters at higher efficiency than the ones reported in literature up to now

Selecting Metal Alloy Electric Contact Materials for MEMS Switches

This paper presents a method for selecting metal alloys as the electric contact materials for microelectromechanical systems (MEMS) metal contact switches. This procedure consists of reviewing macro-switch lessons learned, utilizing equilibrium binary alloy phase diagrams, obtaining thin film material properties and, based on a suitable model, predicting contact resistance performance. After determining a candidate alloy material, MEMS switches were designed, fabricated and tested to validate the alloy selection methodology. Minimum average contact resistance values of 1.17 and 1.87 Ω were measured for micro-switches with gold (Au) and gold–platinum (Au–(6.3%)Pt) alloy electric contacts, respectively. In addition, \u27hot-switched\u27 life cycle test results of 1.02 × 108 and 2.70 × 108 cycles were collected for micro-switches with Au and Au–(6.3%)Pt contacts, respectively. These results indicate increased wear with a small increase in contact resistance for MEMS switches with metal alloy electric contacts

A Current-Dependent Switching Strategy for Si/SiC Hybrid Switch-Based Power Converters

Abstract: Hybrid switches configured by paralleling Silicon (Si) Insulated Gate Bipolar Transistors (IGBT) and Silicon Carbide (SiC) Metal-Oxide Semiconductor Field-Effect Transistors (MOSFET) have been verified to be a high-efficiency cost-effective device concept. In this paper, a current-dependent switching strategy is introduced and implemented to further improve the performance of Si/SiC hybrid switches. This proposed switching strategy is based on a comprehensive consideration of reducing device losses, reliable operation, and overload capability. Based on the utilization of such Si/SiC hybrid switches and the proposed switching strategy, a 15-kW single-phase H-bridge inverter prototype was implemented and tested in the laboratory. Simulation and experimental results are given to verify the performance of the hybrid switches and the new switching strategy