Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/3804
Wed, 23 Aug 2017 06:30:40 GMT2017-08-23T06:30:40ZA discrete-time approach to the steady-state and stability analysis of distributed nonlinear autonomous circuits
http://hdl.handle.net/2117/106912
A discrete-time approach to the steady-state and stability analysis of distributed nonlinear autonomous circuits
Bonet Dalmau, Jordi; Palà Schönwälder, Pere; Miró Sans, Joan Maria
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.
Thu, 27 Jul 2017 09:00:31 GMThttp://hdl.handle.net/2117/1069122017-07-27T09:00:31ZBonet Dalmau, JordiPalà Schönwälder, PereMiró Sans, Joan MariaWe 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.Análisis de circuitos autónomos no lineales con parámetros distribuidos mediante técnicas temporales discretas
http://hdl.handle.net/2117/106645
Análisis de circuitos autónomos no lineales con parámetros distribuidos mediante técnicas temporales discretas
Bonet Dalmau, Jordi; Palà Schönwälder, Pere; Miró Sans, Joan Maria
Thu, 20 Jul 2017 10:18:16 GMThttp://hdl.handle.net/2117/1066452017-07-20T10:18:16ZBonet Dalmau, JordiPalà Schönwälder, PereMiró Sans, Joan MariaReceptor superregenerativo para comunicaciones opticas no guiadas
http://hdl.handle.net/2117/105963
Receptor superregenerativo para comunicaciones opticas no guiadas
Miguel López, José María; Moncunill Geniz, Francesc Xavier; Puerta Notario, Antonio
Wed, 28 Jun 2017 16:03:59 GMThttp://hdl.handle.net/2117/1059632017-06-28T16:03:59ZMiguel López, José MaríaMoncunill Geniz, Francesc XavierPuerta Notario, AntonioConsideraciones sobre el diseño de los sistemas para comunicaciones opticas no guiadas
http://hdl.handle.net/2117/105955
Consideraciones sobre el diseño de los sistemas para comunicaciones opticas no guiadas
Puerta Notario, Antonio; Miguel López, José María; Miró Sans, Joan Maria; Sanz Postils, Margarita
Wed, 28 Jun 2017 14:52:03 GMThttp://hdl.handle.net/2117/1059552017-06-28T14:52:03ZPuerta Notario, AntonioMiguel López, José MaríaMiró Sans, Joan MariaSanz Postils, MargaritaA 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.
Fri, 05 May 2017 13:34:53 GMThttp://hdl.handle.net/2117/1041302017-05-05T13:34:53ZMoncunill 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.
Fri, 28 Apr 2017 16:48:48 GMThttp://hdl.handle.net/2117/1038622017-04-28T16:48:48ZÁguila 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.
Thu, 27 Apr 2017 16:23:14 GMThttp://hdl.handle.net/2117/1038032017-04-27T16:23:14ZBonet 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.
Tue, 28 Feb 2017 15:34:46 GMThttp://hdl.handle.net/2117/1017172017-02-28T15:34:46ZPalà 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.
Mon, 13 Feb 2017 14:26:09 GMThttp://hdl.handle.net/2117/1009272017-02-13T14:26:09ZPalà 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.
Tue, 15 Mar 2016 14:51:23 GMThttp://hdl.handle.net/2117/844082016-03-15T14:51:23ZMiró 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.