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Nomenclatura Unesco > (22) Física > (2203) Electrónica > (2203.02) Elementos de circuitos

Categorías relacionadas:
(3307.03) Diseño de circuitos

Mostrando recursos 1 - 20 de 429

1. A 530-GHz Balanced Mixer - Goutam Chattopadhyay; Student Member; Frank Rice; David Miller; Henry G. Leduc; Jonas Zmuidzinas
Abstract — We report on the design and performance of a 530-GHz balanced SIS mixer, the first balanced mixer in this frequency range. This quasi-optical balanced mixer utilizes a cross-slot antenna on a hyperhemispherical substrate lens with eight superconductor–insulator–superconductor (SIS) junctions and a 180 lumped element IF hybrid circuit. The local oscil-lator (LO) and the radio frequency (RF) signal, orthogonal in polarization to each other, are coupled to the mixer using a wire-grid polarizer. The noise performance of the mixer is excellent, giving an uncorrected receiver noise temperature of 105 K (DSB) at 528 GHz. Index Terms — Balanced mixer,...

2. An Electronic Photoreceptor Sensitive to Small Changes in Intensity - Delbrück, T.; Mead, C. A.
We describe an electronic photoreceptor circuit that is sensitive to small changes in incident light intensity. The sensitivity to changes in the intensity is achieved by feeding back to the input a filtered version of the output. The feedback loop includes a hysteretic element. The circuit behaves in a manner reminiscent of the gain control properties and temporal responses of a variety of retinal cells, particularly retinal bipolar cells. We compare the thresholds for detection of intensity increments by a human and by the circuit. Both obey Weber's law and for both the temporal contrast sensitivities are nearly identical.

3. Counting and Integrating Readout for Direct Conversion X-ray Imaging: Concept, Realization and First Prototype Measurements - Edgar Kraft; Peter Fischer; Michael Karagounis; Manuel Koch; Hans Krueger; Ivan Peric; Norbert Wermes; Christoph Herrmann; Augusto Nascetti; Michael Overdick; Walter Ruetten
Abstract—A novel signal processing concept for X-ray imaging with directly converting pixelated semiconductor sensors is pre-sented. The novelty of this approach compared to existing con-cepts is the combination of charge integration and photon counting in every single pixel. Simultaneous operation of both signal pro-cessing chains extends the dynamic range beyond the limits of the individual schemes and allows determination of the mean photon energy. Medical applications such as X-ray computed tomography can benefit from this additional spectral information through im-proved contrast and the ability to determine the hardening of the tube spectrum due to attenuation by the scanned object. A...

4. [7] [8] [9] [10] - Reactive Elements; G. S. Hobs
negative differential mobility element in a circuit containing

5. Dr. Devendra Garg - Final Report Pi; Director Dr. Devendra Garg; Pi Dr. Loc Vu-quoc
This paper presents a rational approach to construct thermal circuit networks equivalent to a discretization of the heat equation by the finite element method. Elemental thermal circuit networks are developed, which correspond to the linear and cubic Hermite elements in the 1-D case, to the triangular and rectangular elements in the 2-D case, and to the tetrahedral and cube elements in the 3-D case. These thermal circuit networks are to be 18 Nov 1997, 12:21

6. Designing C-elements for Testability - Oleg Petlin Steve; Oleg Petlin; Steve Furber; Steve Furber; O. A. Petlin; S. B. Furber
: C-elements are used widely in asynchronous VLSI circuits. Fabrication faults in some CMOS C-elements can be undetectable by logic testing. Testable designs of static symmetric and asymmetric C-elements are given in this report which provide for the detection of single line stuck-at and stuck-open faults. We show that driving feedback transistors in the proposed testable static C-elements transforms their sequential functions into combinational AND and OR functions or into repeaters of one of their inputs depending on the driving logic value. This simplifies the testing of asynchronous circuits which incorporate a large number of state holding elements. The scan...

7. Synchronous Generator Subtransient Reactance Prediction Using Transient Circuit Coupled Electromagnetic Analyses & Odd Periodic Symmetry - Joshua Lorenz; John T. Fowler
For synchronous 3 phase electrical generator machine design, the ability to predict the subtransient reactance of a particular machine design is of prime importance. The subtransient reactance has a significant impact on the magnitude of the fault currents generated within the machine during an event such as a 3 phase short-circuit. Power system designers routinely use the generator subtransient reactance as a key parameter to aid in the design of the complete power generation system. For new generator designs the subtransient reactance is routinely tested for as part of a thorough evaluation of the generator performance characteristics. In this paper,...

8. Detecting Fabrication Faults in C-elements - O. A. Petlin; S. B. Furber
C-elements are used widely in asynchronous VLSI circuits. Fabrication faults in some C-elements can be undetectable by logic testing. Testable designs of static CMOS Celements are given in this paper which provide for the detection of single line stuck-at and stuck-open faults. We show that driving the feedback transistors in the proposed testable static C-element transforms its sequential function into a combinational AND or OR function depending on the driving logic value. This simplifies the testing of asynchronous circuits which incorporate a large number of state holding elements. The scan testable Celement described can be used in scan testing of...

9. Band-Pass Continuous-Time Sigma-Delta Modulators with Widely Tunable Notch Frequency for Efficient RF-to-Digital Conversion - Molina-Salgado, G.; Jovanivik-Dolecek, G.; Rosa Utrera, José Manuel de la
This paper presents a design methodology to synthesize band-pass continuous-time Sigma-Delta modulators with a widely programmable notch frequency for the efficient digitization of radio-frequency signals in the next generation of software-defined-radio mobile systems. The presented modulator architectures are based on a fourth-order loop filter ¿ implemented with two LC-based resonators ¿ and a finite- impulsive-response feedback loop to increase their flexibility and degrees of freedom, considering three different cases for the digital-to-analog converter waveform, namely: a return-to-zero, a non-return-to-zero and a raised-cosine waveform. In all cases, the notch frequency can be reconfigured from 0.1fs to 0.4fs, while keeping the noise...

10. Low impedance printed circuit radiating element - Martinko, John D.; Rahm, James K.; Frankievich, Robert H.
A printed circuit radiating element comprises a geometrically symmetric planar area of a conducting material separated from a ground plane by a dielectric medium. The driving point of the radiating element is at the base of a notch in one side thereof so that the driving impedance is reduced from that obtained when the element is driven at its edge. Symmetrically disposed on opposite sides of an axis of symmetry of the element along which the driving point lies are two notches which restore the electrical symmetry of the radiating element thereby to suppress higher order modes. The suppression of...

11. Self regulating body bias generator - Hass, Kenneth
The back bias voltage on a functional circuit is controlled through a closed loop process. A delay element receives a clock pulse and produces a delay output. The delay element is advantageously constructed of the same materials as the functional circuit so that the aging and degradation of the delay element parallels the degradation of the functional circuit. As the delay element degrades, the transistor switching time increases, increasing the time delay of the delay output. An AND gate compares a clock pulse to an output pulse of the delay element, the AND output forming a control pulse. A duty...

12. Nonvolatile random access memory - Katti, Romney R.; Wu, Jiin-Chuan; Stadler, Henry L.
A nonvolatile magnetic random access memory can be achieved by an array of magnet-Hall effect (M-H) elements. The storage function is realized with a rectangular thin-film ferromagnetic material having an in-plane, uniaxial anisotropy and inplane bipolar remanent magnetization states. The thin-film magnetic element is magnetized by a local applied field, whose direction is used to form either a 0 or 1 state. The element remains in the 0 or 1 state until a switching field is applied to change its state. The stored information is detcted by a Hall-effect sensor which senses the fringing field from the magnetic storage element....

13. Etude et essais d'un système de mise en contrainte de Si - Pascual Rives, Ivan
La microélectronique a connu, depuis l’invention du transistor dans les années cinquante, un formidable essor. Le transistor, élément de base de tout circuit intégré, est présent à travers des nombreuses applications dans plusieurs domaines comme: l’aviation, l’électroménager, l’automobile, l’informatique, le spatial…Grâces aux progrès accomplis en microélectronique, le monde qui nous entoure a véritablement évolué.Il y a quelques années de nombreuses applications étaient réservées à des professionnels ou dans le cas plus général à des domaines spécifiques, puis celles-ci ont rapidement investi le domicile du particulier et tout son environnement. Parmi les nouvelles applications, les exemples suivants illustrent bien les modifications...

14. Finite Element Modeling of Microfabricated Inductively Coupled Plasma Source with Faraday Shielding - John Onukwugha Nwagbaraocha
For over 100 years inductively coupled plasmas (ICP) sources have been created and studied. ICP sources uses an inductive circuit element adjacent to (or immersed inside) a discharge region in order to couple energy from an RF power source to an ionized gas. Large scale ICP sources have been used for material processing. The focus of this paper will be small scale ICP sources which can be used for analytical instrumentation and for electric propulsion systems. Many of the characteristics of a miniaturized plasma source are the same as that of its large-scale counterparts. Capacitive coupling to the plasma occurs...

15. A magnetoelectronic macrocell employing reconfigurable threshold logic, to appear - Steve P. Ferrera; Nicholas P. Carter
In this paper, we introduce a reconfigurable fabric based around a new class of circuit element: the hybrid Hall effect (HHE) magnetoelectronic device. Because they incorporate a ferromagnetic element, HHE devices are inherently non-volatile, retaining their state without a power supply. In addition, HHE devices are extremely well-suited to implementing threshold logic circuits, which allows many complex logic functions to be implemented in fewer gates than are required in systems based on AND-OR logic. We present the design of an HHE-based reconfigurable macrocell based on two-level threshold logic that can be configured on a cycle-by-cycle basis while internally storing non-volatile...

16. MATLAB Partial Element Equivalent Circuit Toolbox for Solving Coupled Electromagnetic-Circuit Problems - Vjosa Shatri *a; Ruzhdi Sefa B; Lavdim Kurtaj C
Performance of Partial Element Equivalent Circuit (PEEC) Toolbox for MATLAB for solving coupled electromagneticcircuit problems is presented. Geometry of the problems to be solved is described with wire-based language, specifically designed for this toolbox, by using predefined basic elements. Meshing function will discretize geometry, or parts of it, with selected 1D, 2D, 2DS, 3D, or 3Dxyz mesh type, and will generate surface and volume cells as required by PEEC method. Choice of mesh type is trade-off between model size and accuracy. Calculation of partial elements is handled by FastCap2 and FastHenry2. Toolbox offers interface to these applications starting from discretized...

17. Fabricación y Caracterización de dispositivos basados en Silicio Poroso sobre c-Si. Aplicaciones eléctricas, Ópticas y Térmicas. - Fonthal Rico, Faruk
Debido a las propiedades eléctricas y ópticas del Silicio Poroso (PS), este es un material ampliamente utilizado para el desarrollo de los dispositivos electrónicos. Por su compatibilidad con la tecnología de fabricación del Silicio, el Silicio Poroso es estudiado hoy en día en diferentes aplicaciones como: elementos activos en circuitos integrados, estructuras electro luminiscentes, dispositivos fotodetectores, dispositivos térmicos y muchas más.El trabajo que se ha desarrollado como tesis doctoral consiste en estudiar, fabricar y caracterizar estructuras basadas en PS en diferentes medios como el luminoso y el térmico, para 1) establecer sus diferentes comportamientos y 2) desarrollo de dispositivos basados...

18. Análisis y Optimización de Circuitos Autónomos Mediante Técnicas Temporales Discretas - Palà Schönwälder, Pere
En esta tesis, las ecuaciones de equilibrio de circuitos no lineales autónomos se plantean discretizando el circuito mediante transformaciones de plano S a plano Z.Tras imponer la periodicidad de las variables resulta una formulación matricial no lineal, planteada íntegramente en el dominio temporal. Se descubre la relación de las ecuaciones así planteadas con las que resultan aplicando el método de balance armónico. Asimismo, se desarrollan expresiones analíticas para el cálculo de las derivadas parciales de las ecuaciones respecto a las muestras de las variables, respecto al periodo de oscilación y respecto a los elementos de circuito, mediante las cuales se...

19. Medida de parámetros de ruido de dispositivos activos basada en fuente adaptada - Maya Sánchez, María del Carmen
En esta Tesis se utiliza una técnica de fuente adaptada para medir los parámetros de ruido de transistores de efecto campo, como MESFET y HEMT. Para ello, se ha implementado un sistema de medida en el margen de frecuencias de 2-75 GHz, de 2-50 GHz para medidas de dispositivos en oblea y de 50-75 GHz en guía de onda. Sin embargo, en este margen de frecuencias las pérdidas de los dispositivos aumentan, el nivel del ENR de la fuente de ruido, utilizada para calibrar el sistema, es menor y la sensibilidad a la precisión en la medida de potencia es...

20. Thin-film bulk acoustic wave resonators - FBAR: fabrication, heterogeneous integration with CMOS technologies and sensor applications - Campanella Pineda, Humberto
El gran impacto de la tecnología FBAR tanto en sistemas de radio frecuencia como más recientemente en sensores han motivado el desarrollo de aplicaciones integradas. Esto implica que los procesos de fabricación deberían lograr producir dispositivos resonadores con un alto factor de calidad, al tiempo que permitir la integración de los FBAR con tecnologías CMOS estándar. De tal manera, esta tesis doctoral aborda dichos requerimientos, contribuyendo con el diseño, fabricación y caracterización de resonadores FBAR; su integración con tecnologías CMOS estándar; y su aplicación a sistemas de sensores. El desarrollo de la tecnología de fabricación de los FBAR ha involucrado...

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