Novel active-compensated weighted summer

A summer amplifier with extended bandwidth is proposed. Compensation of the frequency characteristics is achieved by employing two operational amplifiers instead of external reactive components

On the Active Compensation of Operational Amplifier Based VCVS

A unified treatment of the active compensation for VCVS realized by operational amplifiers is presented. It is a summary of low-sensitivity circuit structures which can be either magnitude or phase compensated. The performance of such a circuits is discussed in detail. Experimental data for some of them are also included

Biogás como combustible alternativo en automoción

Actualmente muchas investigaciones se centran en la búsqueda de combustibles alternativos para cumplir con las necesidades de transporte y reducir el impacto ambiental en automoción. El uso de combustibles gaseosos en el sector del transporte es una opción prometedora además de promover la diversificación energética. Los combustibles se clasifican en función de las propiedades de los mismos, centrándose este trabajo en el estudio del biogás, sus aplicaciones, las infraestructuras de almacenamiento y su transporte a través de la red de gas natural.Posteriormente se describen los diferentes tipos de vehículos de gas natural comprimido, en función de su construcción, tipos de recarga, seguridad y emisiones. También se describen las estaciones de servicio.Se ha realizado un análisis para los motores de encendido provocado (MEP)y encendido por compresión (MEC) alimentados con biogás de los siguientes parámetros:presíón media efectiva (BMEP), la eficiencia térmica (BTE), temperatura de los gases de escape, las variaciones en el grado de avance del motor, sincronización de la chispa y la introducción de hidrógeno en la mezcla. Finalmente, se han estudiado también las emisiones de óxidos de nitrógeno, monóxido de carbono, hidrocarburos no quemados y partículas en diferentes pruebas para motores MEP y MECDepartamento de Ingeniería Energética y FluidomecánicaMáster en Ingeniería de Automoció

Chaos in a Switched-Capacitor Circuit

We report chaotic phenomena observed from a simple nonlinear switched-capacitor circuit. The experimentally measured bifurcation tree diagram reveals a period-doubling route to chaos. This circuit is described by a first-order discrete equation which can be transformed into the logistic map whose chaotic dynamics is well known.National Science Foundation ECS-8542885Comisión Interministerial de Ciencia y Tecnología 0245/81Office of Naval Research under Contract NOOO14-76-C-057

A new nonlinear time-domain op-amp macromodel using threshold functions and digitally controlled network elements

A general-purpose nonlinear macromodel for the time-domain simulation of integrated circuit operational amplifiers (op amps), either bipolar or MOS, is presented. Three main differences exist between the macromodel and those previously reported in the literature for the time domain. First, all the op-amp nonlinearities are simulated using threshold elements and digital components, thus making them well suited for a mixed electrical/logical simulator. Secondly, the macromodel exhibits a superior performance in those cases where the op amp is driven by a large signal. Finally, the macromodel is advantageous in terms of CPU time. Several examples are included illustrating all of these advantages. The main application of this macromodel is for the accurate simulation of the analog part of a combined analog/digital integrated circui

Design of RC-active oscillators using composite amplifiers

The design of composite opamp Wien-Bridge oscillators is systematically approached by using a general model including amplitude control issues. Two different design criteria are presented and their main features summarized. A general composite opamp topology from which a catalog of structures can be obtained in a systematic way is presented. Experimental data are included illustrating the performance of the proposed design criteria

New analogue switch circuit having very low forward resistance

A new circuit realisation for an analogue switch is reported. The main feature of the proposed design is the low value of the forward resistance as compared with commercial switches. Experimental data confirming the performance of the circuit are also included

An advanced symbolic analyzer for the automatic generation of analog circuit design equations

A tool for symbolic analysis of analog integrated circuits is presented featuring accurate simplification, pole/zero extraction, and tools for parametric AC circuit characterization. The program, called ASAP, uses signal flowgraph methods and has been written in C for portability. In its current version, ASAP is able to deal with the complexity levels arising in typical analog building blocks when described by device-level models. The ASAP inputs and outputs, the architecture, and the graphical interface are discussed

Application of piecewise-linear switched-capacitor circuits for random number generation

An unconventional application of switched-capacitor (SC) circuits is discussed. A systematic method for the design of piecewise-linear (PL) parasitic-insensitive SC chaotic discrete maps is given. A simple circuit which generates a random one-bit digital sequence is reported. Simulation results show that the random behavior is not significantly altered by large (about 5%) variations in the values of the design parameters, which makes monolithic implementation feasible. Simulation results and layout for a 2- mu m double-metal CMOS prototype are included