Transpose return relation method for designing low noise oscillators

In this paper, a new linear method for optimizing compact low noise oscillators for RF/MW applications will be presented. The first part of this paper makes an overview of Leeson's model. It is pointed out, and it is demonstrates that the phase noise is always the same inside the oscillator loop. It is presented a general phase noise optimization method for reference plane oscillators. The new method uses Transpose Return Relations (RRT) as true loop gain functions for obtaining the optimum values of the elements of the oscillator, whatever scheme it has. With this method, oscillator topologies that have been designed and optimized using negative resistance, negative conductance or reflection coefficient methods, until now, can be studied like a loop gain method. Subsequently, the main disadvantage of Leeson's model is overcome, and now it is not only valid for loop gain methods, but it is valid for any oscillator topology. The last section of this paper lists the steps to be performed to use this method for proper phase noise optimization during the linear design process and before the final non-linear optimization. The power of the proposed RRT method is shown with its use for optimizing a common oscillator, which is later simulated using Harmonic Balance (HB) and manufactured. Then, the comparison of the linear, HB and measurements of the phase noise are compared.

Comments and remarks over classic linear loop-gain method for oscillator design and analysis. New proposed method based on NDF/RRT

Abstract. This paper describes a new and original method for designing oscillators based on the Normalized Determinant Function (NDF) and Return Relations (RRT)- Firstly, a review of the loop-gain method will be performed. The loop-gain method pros, cons and some examples for exploring wrong solutions provided by this method will be shown. This method produces in some cases wrong solutions because some necessary conditions have not been fulfilled. The required necessary conditions to assure a right solution will be described. The necessity of using the NDF or the Transpose Return Relations (RRT), which are related with the True Loop-Gain, to test the additional conditions will be demonstrated. To conclude this paper, the steps for oscillator design and analysis, using the proposed NDF/RRj method, will be presented. The loop-gain wrong solutions will be compared with the NDF/RRj and the accuracy of this method to estimate the oscillation frequency and QL will be demonstrated. Some additional examples of plane reference oscillators (Z/Y/T), will be added and they will be analyzed with the new NDF/RRj proposed method, even these oscillators cannot be analyzed using the classic loop gain method.

Fluoro-sensing applied to detection and identification of hydrocarbons in inland waters. Study of the impact of different UV light sources

This paper presents the detection and identification of hydrocarbons through flu oro-sensing by developing a simple and inexpensive detector for inland water, in contrast to current systems, designed to be used for marine waters at large distances and being extremely costly. To validate the proposed system, three test-benches have been mounted, with various UV-Iight sources. Main application of this system would be detect hydrocarbons pollution in rivers, lakes or dams, which in fact, is of growing interest by administrations.

Diseño y optimización de ruido de fase en osciladores utilizando la NDF.

In this paper the use of the NDF is proposed as a general method suitable for analysing any oscillator topology. The most important advantage of this method is that it provides an unique procedure to analyse any oscillator. It also makes possible the phase noise optimization in the linear design phase for any oscillator. An additional advantage of this method is that it does not require any proviso verification as all classic methods need. The use of the NDF method is illustrated with the design of two examples. These two oscillators are manufactured and the simulation results are compared with the measurements showing good agreement. These results confirm the excellent possibilities of the proposed method for low noise oscillators design.

Análisis y Diseño de Algoritmos de Control Discreto de Sistemas MIMO Lineales y No Lineales Aplicando Técnicas de Control de Estructura Variable

Dentro de las técnicas de control de procesos no lineales, los controladores de estructura variable con modos deslizantes (VSC-SM en sus siglas en inglés) han demostrado ser una solución robusta, por lo cual han sido ampliamente estudiados en las cuatro últimas décadas. Desde los años ochenta se han presentado varios trabajos enfocados a especificar controladores VSC aplicados a sistemas de tiempo discreto (DVSC), siendo uno de los mayores intereses de análisis obtener las mismas prestaciones de robustez e invarianza de los controladores VSC-SM. El objetivo principal del trabajo de Tesis Doctoral consiste en estudiar, analizar y proponer unos esquemas de diseño de controladores DVSC en procesos multivariable tanto lineales como no lineales. De dicho estudio se propone una nueva filosofía de diseño de superficies deslizantes estables donde se han considerado aspectos hasta ahora no estudiados en el uso de DVSC-SM como son las limitaciones físicas de los actuadores y la dinámica deslizante no ideal. Lo más novedoso es 1) la propuesta de una nueva metodología de diseño de superficies deslizantes aplicadas a sistemas MIMO lineales y la extensión del mismo al caso de sistemas multivariables no lineales y 2) la definición de una nueva ley de alcance y de una ley de control robusta aplicada a sistemas MIMO, tanto lineales como no lineales, incluyendo un esquema de reducción de chattering. Finalmente, con el fin de ilustrar la eficiencia de los esquemas presentados, se incluyen ejemplos numéricos relacionados con el tema tratado en cada uno de los capítulos de la memoria. ABSTRACT Over the last four decades, variable structure controllers with sliding mode (VSC-SM) have been extensively studied, demonstrating to be a robust solution among robust nonlinear processes control techniques. Since the late 80s, several research works have been focused on the application of VSC controllers applied to discrete time or sampled data systems, which are known as DVSC-SM, where the most extensive source of analysis has been devoted to the robustness and invariance properties of VSC-SM controllers when applied to discrete systems. The main aim of this doctoral thesis work is to study, analyze and propose a design scheme of DVSC-SM controllers for lineal and nonlinear multivariable discrete time processes. For this purpose, a new design philosophy is proposed, where various design features have been considered that have not been analyzed in DVSC design approaches. Among them, the physical limitations and the nonideal dynamic sliding mode dynamics. The most innovative aspect is the inclusion of a new design methodology applied to lineal sliding surfaces MIMO systems and the extension to nonlinear multivariable systems, in addition to a new robust control law applied to lineal and nonlinear MIMO systems, including a chattering reduction scheme. Finally, to illustrate the efficiency of the proposed schemes, several numerical examples applied to lineal and nonlinear systems are included.

Propuesta metodológica para la aplicación de créditos ECTS en Lingüística

En este artículo describimos y presentamos los resultados del proyecto de investigación que desarrollamos durante el curso 2005-2006, cuyo objetivo era elaborar una Guía Docente de la asignatura de Lingüística, troncal de primer curso en las titulaciones de Filología. La guía ha sido diseñada de acuerdo con las directrices del Espacio Europeo de Educación Superior y el nuevo sistema de créditos europeos (ECTS), siguiendo cinco elementos fundamentales: requisitos de la asignatura, objetivos y competencias, contenidos, metodología y evaluación. Creemos que la armonización de la enseñanza y de las titulaciones europeas exige que tanto profesores como alumnos nos involucremos en este proceso. Esperamos que esta propuesta sirva de pauta para la elaboración de futuras guías docentes de otras asignaturas de similares características en los estudios de Filología.

Plurilingüismo y aprendizaje cooperativo en el diseño de prácticas de Lingüística

Este artículo presenta el trabajo realizado desde el área de Lingüística General de la Universidad de Alicante para ofertar sus prácticas de la asignatura “Lingüística General II”, común a todas las especialidades de lenguas modernas de la Facultad de Filosofía y Letras, en los tres idiomas en que tiene lugar la docencia de dichas clases: castellano, valenciano e inglés. A fin de armonizar los contenidos prácticos de una enseñanza trilingüe, por un lado, y de fomentar la implicación del alumnado en las actividades prácticas y contribuir al desarrollo del aprendizaje colaborativo en el aula, por otro, los profesores de este área de conocimiento, junto con la participación de dos estudiantes, han diseñado veinte prácticas que van desde el análisis del signo lingüístico hasta la Pragmática, pasando por la Fonética, la Morfología, la Sintaxis y el Análisis del Discurso.

Ensayos y poemas /

Mode of access: Internet.

Give 'em the ax /

Mode of access: Internet.

Essays in order /

Each essay is also published separately under its own title by Sheed and Ward, London, as no.1-3 of the series Essays in order.

Manual de historia de la civilización argentina;

Bibliography at end of each chapter.

The true believer : his character, duty, and privileges, elucidated in a series of discourses /

Mode of access: Internet.

Progress in the study of the depths of oceans, USSR.

Translation of articles which originally appeared in Itoginauki: Dostizhenii︠a︡ okeanologii, 1959.

Uncle Sam in the Pacific Northwest; Federal management of natural resources in the Columbia River Valley.

Mode of access: Internet.