A. Etxebarria

An educational environment for VHDL hardware description language using the WWW and specific workbench

In this paper, an educational environment for the hardware description language (VHDL) is described. There are three parts that make up this environment: to teach students the fundamental concepts in theory, to design and simulate digital circuits and finally, to check the behavior of the real programmable logic devices (PLD). The theoretical tutorial and the practical manual for the simulations, both evolved using hypertext mark-up language (HTML), allow students to follow the course from any point of the planet through the World Wide Web (WWW). In order to achieve the above mentioned goals, a board has been specifically designed. This device is connected to a shared personal computer. The data transmission and the control of the board has been developed based on a set of Virtual Instruments (VI) designed over LabView (Laboratory Virtual Instrument Engineering Workbench from National Instrument) which is a graphical programming, language that has been widely adopted throughout industry, academia, and research lab as a standard for data acquisition, and instrument control software.

Power electronics and basic electronics real experiments through the World Wide Web

The increasing diffusion and development of information and communication technologies has allowed the introduction of new techniques, such as virtual laboratories, in the world of research and education. The main feature of these laboratories is the remote control of the applications that are developed in the local laboratory and the remote data acquisition and treatment that can be carried out from any point of the planet. This paper focuses on the new equipment, based on specific software and hardware, dedicated to the power electronics and basic electronics teaching through remote HTTP network access. Besides, a novel methodology based on real-time data transfer and interactive applications is presented here. This methodology has been developed on a set of virtual instruments designed over Lab View.

Adaptive control of printing devices using fractional-order hold circuits adjusted through neural networks

Abstract A connectionist method for autotuning the free parameter of a fractional-order hold (FROH) circuit in order to improve the performance of the digitally controlled systems is proposed. Such a technique employs multilayer perceptrons to approximate the mapping between the sampling period/continuous-time parameters of the estimated plant and the optimal value of the FROH adjustable gain. In this way, adaptive discretization systems to improve the stability properties of the resulting discrete-time zeros are implemented. Simulation results are presented in order to illustrate the properties of the complete system applied to two actual digitally controlled printing devices (HP 7090A and low-cost computer printer).