A discrete-time approach to the steady-state and stability analysis of distributed nonlinear autonomous circuits

We present a direct method for the steady-state and stability analysis of autonomous circuits with transmission lines and generic nonlinear elements. With the discretization of the equations that describe the circuit in the time domain, we obtain a nonlinear algebraic formulation where the unknowns to determine are the samples of the variables directly in the steady state, along with the oscillation period, the main unknown in autonomous circuits. An efficient scheme to build the Jacobian matrix with exact partial derivatives with respect to the oscillation period and with respect to the samples of the unknowns is described. Without any modification in the analysis method, the stability of the solution can be computed a posteriori constructing an implicit map, where the last sample is viewed as a function of the previous samples. The application of this technique to the time-delayed Chua's circuit (TDCC) allows us to investigate the stability of the periodic solutions and to locate the period-doubling bifurcations.Peer ReviewedPostprint (published version

Comunicaciones opticas no guiadas. Fotobalizaje

After a brief overview of unguided optical communications, this paper presents a system for intelligent photo-buoying of vehicles which has been implementad into a public transport controlling system in a urban traffic environment. The system utilizes a infrared bidirectional communication link for demanded data transmission from buoy to vehicle. Experimental results clearly show that infrared radiation-based systems, instead of the more frequently used microwaves-based, may offer a feasible and competitiva solution in certain types of traffic flow improvement applications.Peer ReviewedPostprint (published version

Circuits i sistemes lineals: col·lecció de problemes

2019/202

Prototipo experimental para ver y oir la dinámica caótica en un circuito

Chaos, apparently disordered behaviour which is nonetheless deterministic, is a universal phenomenon which occurs in many systems in all areas of science. For it to have place, the equations describing the situation must be nonlinear. In this paper chaos is introduced via an actual circuit and, by using a digital storage osciloscope and an integrated audio amplifier, it possible to get sights and sounds of chaos.Peer ReviewedPostprint (published version

Sistemas de temporización con el µC TMS 1000, aplicaciones de consumo

Los µC monopastilla se prestan especialmente para las llamadas Aplicaciones de Consumo por su reducido precio en grandes series. Entre dichas aplicaciones destacan los sistemas de temporización, ampliamente utilizados en el control de electrodomésticos. Los sistemas que incorporan el pe superan a los realizados con lógica cableada, ya que con el mismo "hard­ware" y distintos programas pueden realizar funciones muy diversas y de gran complejidad, Otras ventajas derivan de su mayor precisión y fiabilidad, de la gran­ reducción de componentes que suponen, dado el grado de integración alcanzado y de la importante disminu­ción del coste unitario. En esta comunicación se presenta el diseño de un sis­tema de temporización para hornos domésticos, con el µC TMS 1000, realizado en el Departamento y en fase de fabricación

An explicit method for modeling lossy and dispersive transmission lines

In this paper, an explicit -non iterative- method for modeling lossy and dispersive transmission lines, allowing the inclusion of skin-effect parameters is described. This method, based on multipoint Padé approximation, allows direct implementation to obtain models for existing simulation program -such as SPICE-without the need of making use of optimization algorithms at any stage. Examples are given to show that the described procedure yields the same accuracy as other existing techniques that do require this iterative approach.Peer Reviewe

Worker protection at crocodile (alligator) shears

SIGLEAvailable from British Library Document Supply Centre- DSC:4224.8495(HSE-GN-PM--65) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

CiOpt: a program for optimization of the frequency response of linear circuits

An interactive personal-computer program for optimizing the frequency response of linear lumped circuits (CiOpt) is presented. CiOpt has proved to be an efficient tool in improving designs where the inclusion of more accurate device models distorts the desired frequency response, as well as in device modeling. The outputs of CiOpt are the element values which best match the obtained and the desired frequency response. The optimization algorithms used (the Fletcher-Powell and Newton's methods, which, respectively, make use of approximate and exact second-order sensitivities) are fully described in DFD form. Analysis is carried out by obtaining the symbolic form of the transfer function H(s). An application example is presentedPeer Reviewe

A discrete-time equivalent system approach to the periodic response of nonlinear autonomous circuits

The problem of computing the steady state response of nonlinear autonomous circuits is solved making use of a discrete-time equivalent system approach. With the application of an s-plane to z-plane mapping, the circuit equations are discretized and written in vector form. Using this technique, it is not necessary to repeatedly compute transforms between the time and the frequency domain. An efficient scheme to build the Jacobian matrix with exact partial derivatives with respect to the oscillation period and with respect to the samples of the unknown variables is described. Application examples on two widely studied circuits are provided to validate the proposed technique.Peer Reviewe

CiOpt: a program for optimization of the frequency response of linear circuits

An interactive personal-computer program for optimizing the frequency response of linear lumped circuits (CiOpt) is presented. CiOpt has proved to be an efficient tool in improving designs where the inclusion of more accurate device models distorts the desired frequency response, as well as in device modeling. The outputs of CiOpt are the element values which best match the obtained and the desired frequency response. The optimization algorithms used (the Fletcher-Powell and Newton's methods, which, respectively, make use of approximate and exact second-order sensitivities) are fully described in DFD form. Analysis is carried out by obtaining the symbolic form of the transfer function H(s). An application example is presentedPeer Reviewe