Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/3804
2017-05-29T02:06:17ZA direct-sequence spread-spectrum super-regenerative receiver
http://hdl.handle.net/2117/104130
A direct-sequence spread-spectrum super-regenerative receiver
Moncunill Geniz, Francesc Xavier; Mas Casals, Orestes Miquel; Palà Schönwälder, Pere
Current applications of the super-regenerative receiver use narrowband modulations. In this paper a new architecture that allows incoherent detection of spread-spectrum signals is presented. A pseudorandom code generator has been added to the original circuit. It is clocked by the quench oscillator and takes advantage of the characteristic broad reception bandwidth. CDMA can be achieved via ASK and FSK modulated signals with high simplicity in the RF stage as well as low power consumption.
2017-05-05T13:34:53ZMoncunill Geniz, Francesc XavierMas Casals, Orestes MiquelPalà Schönwälder, PereCurrent applications of the super-regenerative receiver use narrowband modulations. In this paper a new architecture that allows incoherent detection of spread-spectrum signals is presented. A pseudorandom code generator has been added to the original circuit. It is clocked by the quench oscillator and takes advantage of the characteristic broad reception bandwidth. CDMA can be achieved via ASK and FSK modulated signals with high simplicity in the RF stage as well as low power consumption.Steady state analysis of class-E amplifier with non-linear capacitor by means of discrete-time techniques
http://hdl.handle.net/2117/103862
Steady state analysis of class-E amplifier with non-linear capacitor by means of discrete-time techniques
Águila López, Francisco del; Palà Schönwälder, Pere; Bonet Dalmau, Jordi; Giralt Mas, Ma. Rosa
A new method to determine the steady state response of switched nonlinear circuits is proposed. The method is based on a Gear discretization of the circuit equations. Additional samples of the waveform are used to describe the circuit when switching from one topology to another. Results are presented for a class-E resonant inverter.
2017-04-28T16:48:48ZÁguila López, Francisco delPalà Schönwälder, PereBonet Dalmau, JordiGiralt Mas, Ma. RosaA new method to determine the steady state response of switched nonlinear circuits is proposed. The method is based on a Gear discretization of the circuit equations. Additional samples of the waveform are used to describe the circuit when switching from one topology to another. Results are presented for a class-E resonant inverter.Steady state analysis of Chua's circuit with RLCG transmission line
http://hdl.handle.net/2117/103803
Steady state analysis of Chua's circuit with RLCG transmission line
Bonet Dalmau, Jordi; Palà Schönwälder, Pere; Águila López, Francisco del
In this paper we present a new technique to compute the steady state response of nonlinear autonomous circuits with RLCG transmission lines. Using multipoint Pade approximants, instead of the commonly used expansions around s=0 or s/spl rarr//spl infin/ accurate, low-order lumped equivalent circuits of the characteristic impedance and the exponential propagation function are obtained in an explicit way. Then, with the temporal discretization of the equations that describe the transformed circuit, we obtain a nonlinear algebraic formulation where the unknowns to be determined 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 obtained. Steady state solutions of the Chua's circuit with RLCG transmission line are computed for selected circuit parameters.
2017-04-27T16:23:14ZBonet Dalmau, JordiPalà Schönwälder, PereÁguila López, Francisco delIn this paper we present a new technique to compute the steady state response of nonlinear autonomous circuits with RLCG transmission lines. Using multipoint Pade approximants, instead of the commonly used expansions around s=0 or s/spl rarr//spl infin/ accurate, low-order lumped equivalent circuits of the characteristic impedance and the exponential propagation function are obtained in an explicit way. Then, with the temporal discretization of the equations that describe the transformed circuit, we obtain a nonlinear algebraic formulation where the unknowns to be determined 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 obtained. Steady state solutions of the Chua's circuit with RLCG transmission line are computed for selected circuit parameters.A discrete-time equivalent system approach to the periodic response of nonlinear autonomous circuits
http://hdl.handle.net/2117/101717
A discrete-time equivalent system approach to the periodic response of nonlinear autonomous circuits
Palà Schönwälder, Pere; Miró Sans, Joan Maria
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.
2017-02-28T15:34:46ZPalà Schönwälder, PereMiró Sans, Joan MariaThe 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.An explicit method for modeling lossy and dispersive transmission lines
http://hdl.handle.net/2117/100927
An explicit method for modeling lossy and dispersive transmission lines
Palà Schönwälder, Pere; Miró Sans, Joan Maria
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.
2017-02-13T14:26:09ZPalà Schönwälder, PereMiró Sans, Joan MariaIn 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.Sensibilidades de primero y segundo orden en circuitos lineales. Aplicación al desarrollo de un optimizador de la respuesta frecuencial
http://hdl.handle.net/2117/84408
Sensibilidades de primero y segundo orden en circuitos lineales. Aplicación al desarrollo de un optimizador de la respuesta frecuencial
Miró Sans, Joan Maria; Palà Schönwälder, Pere
Since using the Modified Nodal Approach formulation it is possible to obtain exact first and second arder sensitivities of any linear circuit with an affordable computational cost, first and second arder optimization algorithms may be implemented. A personal-computer program (CiOpt) to optimize the frequency response of linear lumped circuits has been implemented. It' s output are the element values that best match the obtained and the desired frequency response. CiOpt has preved to be an efficient tool in device modelling and in improving designs where the inclusion of more accurate device models distorts the desired frequency response. The implemented optimization algorithms -a quasi-Newton method (Fletcher-Powell), Newton's method and an algorithm based on the Levenberg-Marquardt method- are compared on an application example.
2016-03-15T14:51:23ZMiró Sans, Joan MariaPalà Schönwälder, PereSince using the Modified Nodal Approach formulation it is possible to obtain exact first and second arder sensitivities of any linear circuit with an affordable computational cost, first and second arder optimization algorithms may be implemented. A personal-computer program (CiOpt) to optimize the frequency response of linear lumped circuits has been implemented. It' s output are the element values that best match the obtained and the desired frequency response. CiOpt has preved to be an efficient tool in device modelling and in improving designs where the inclusion of more accurate device models distorts the desired frequency response. The implemented optimization algorithms -a quasi-Newton method (Fletcher-Powell), Newton's method and an algorithm based on the Levenberg-Marquardt method- are compared on an application example.CiOpt: a program for optimization of the frequency response of linear circuits
http://hdl.handle.net/2117/84398
CiOpt: a program for optimization of the frequency response of linear circuits
Miró Sans, Joan Maria; Palà Schönwälder, Pere
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 presented
2016-03-15T14:21:54ZMiró Sans, Joan MariaPalà Schönwälder, PereAn 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 presentedComunicaciones opticas no guiadas. Fotobalizaje
http://hdl.handle.net/2117/84393
Comunicaciones opticas no guiadas. Fotobalizaje
Miró Sans, Joan Maria; Miguel López, José María; Sanz Postils, Margarita
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.
2016-03-15T14:07:16ZMiró Sans, Joan MariaMiguel López, José MaríaSanz Postils, MargaritaAfter 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.Prototipo experimental para ver y oir la dinámica caótica en un circuito
http://hdl.handle.net/2117/84384
Prototipo experimental para ver y oir la dinámica caótica en un circuito
Miguel López, José María; Herranz Luis, Jaime; Miró Sans, Joan Maria; Palà Schönwälder, Pere; Sanz Postils, Margarita
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.
2016-03-15T13:36:01ZMiguel López, José MaríaHerranz Luis, JaimeMiró Sans, Joan MariaPalà Schönwälder, PereSanz Postils, MargaritaChaos, 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.Programa de simulación de circuitos analógicos lineales y de capacidades conmutadas
http://hdl.handle.net/2117/83458
Programa de simulación de circuitos analógicos lineales y de capacidades conmutadas
Miró Sans, Joan M.; Puerta Notario, Antonio; Griñó, J.M.; Sanz Postils, Margarita
2016-02-25T17:49:41ZMiró Sans, Joan M.Puerta Notario, AntonioGriñó, J.M.Sanz Postils, Margarita