CIRCUIT - Grup de Recerca en Circuits i Sistemes de Comunicació
http://hdl.handle.net/2117/3801
2017-03-23T16:30:38ZA 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.A discrete-time approach to the steady-state and stability analysis of distributed nonlinear autonomous circuits
http://hdl.handle.net/2117/98495
A discrete-time approach to the steady-state and stability analysis of distributed nonlinear autonomous circuits
Bonet Dalmau, Jordi; Palà Schönwälder, Pere
We present a direct method for the steady-state and stability
analysis of autonomous circuits with transmission lines and generic non-
linear 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 buildtheJacobian matrix with
exact partial derivatives with respect to the oscillation period and with re-
spect to the samples of the unknowns is described. Without any modifica-
tion 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.
2016-12-16T16:30:04ZBonet Dalmau, JordiPalà Schönwälder, PereWe present a direct method for the steady-state and stability
analysis of autonomous circuits with transmission lines and generic non-
linear 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 buildtheJacobian matrix with
exact partial derivatives with respect to the oscillation period and with re-
spect to the samples of the unknowns is described. Without any modifica-
tion 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.Stability analysis of periodic solutions in non-linear autonomous circuits: a discrete time approach
http://hdl.handle.net/2117/97804
Stability analysis of periodic solutions in non-linear autonomous circuits: a discrete time approach
Miró Sans, Joan Maria; Palà Schönwälder, Pere; Mas Casals, Orestes Miquel
Steady-state methods have been devised to compute periodic wave-forms without having to integrate the
autonomous circuit equations until the transients die out. Stability analysis of the computed solutions is the
next topic to be addressed by a steady state circuit simulator. Shooting methods based on Newton's iteration
are expensive in terms of computing time, because each iteration step requires integration of the variational
equation, but directly provide information on the stability of the final On the other hand, when
making use of harmonic balance methods, the stability of the computed solutions is typically investigated
from a continuation point of view.4 Recently a discrete time approach (DTA) was proposed for the analysis
and optimization of non-linear autonomous circuits.' This letter describes how the stability of the
computed periodic wave-forms may be easily determined (I posteriori with no modification to the DTA
solution method.
2016-12-05T16:39:28ZMiró Sans, Joan MariaPalà Schönwälder, PereMas Casals, Orestes MiquelSteady-state methods have been devised to compute periodic wave-forms without having to integrate the
autonomous circuit equations until the transients die out. Stability analysis of the computed solutions is the
next topic to be addressed by a steady state circuit simulator. Shooting methods based on Newton's iteration
are expensive in terms of computing time, because each iteration step requires integration of the variational
equation, but directly provide information on the stability of the final On the other hand, when
making use of harmonic balance methods, the stability of the computed solutions is typically investigated
from a continuation point of view.4 Recently a discrete time approach (DTA) was proposed for the analysis
and optimization of non-linear autonomous circuits.' This letter describes how the stability of the
computed periodic wave-forms may be easily determined (I posteriori with no modification to the DTA
solution method.The Mendeleev-Meyer force project
http://hdl.handle.net/2117/96683
The Mendeleev-Meyer force project
Santos Hernández, Sergio; Lai, Chia-Yun; Amadei, Carlo Alberto; Gadelrab, Karim Raafat; Tang, Tzu-Chieh; Verdaguer Prats, Albert; Barcons Xixons, Víctor; Font Teixidó, Josep; Colchero, Jaimer; Chiesa, Matteo
Here we present the Mendeleev–Meyer Force Project which aims at tabulating all materials and substances in a fashion similar to the periodic table. The goal is to group and tabulate substances using nanoscale force footprints rather than atomic number or electronic configuration as in the periodic table. The process is divided into: (1) acquiring nanoscale force data from materials, (2) parameterizing the raw data into standardized input features to generate a library, (3) feeding the standardized library into an algorithm to generate, enhance or exploit a model to identify a material or property. We propose producing databases mimicking the Materials Genome Initiative, the Medical Literature Analysis and Retrieval System Online (MEDLARS) or the PRoteomics IDEntifications database (PRIDE) and making these searchable online via search engines mimicking Pubmed or the PRIDE web interface. A prototype exploiting deep learning algorithms, i.e. multilayer neural networks, is presented.
2016-11-15T16:04:39ZSantos Hernández, SergioLai, Chia-YunAmadei, Carlo AlbertoGadelrab, Karim RaafatTang, Tzu-ChiehVerdaguer Prats, AlbertBarcons Xixons, VíctorFont Teixidó, JosepColchero, JaimerChiesa, MatteoHere we present the Mendeleev–Meyer Force Project which aims at tabulating all materials and substances in a fashion similar to the periodic table. The goal is to group and tabulate substances using nanoscale force footprints rather than atomic number or electronic configuration as in the periodic table. The process is divided into: (1) acquiring nanoscale force data from materials, (2) parameterizing the raw data into standardized input features to generate a library, (3) feeding the standardized library into an algorithm to generate, enhance or exploit a model to identify a material or property. We propose producing databases mimicking the Materials Genome Initiative, the Medical Literature Analysis and Retrieval System Online (MEDLARS) or the PRoteomics IDEntifications database (PRIDE) and making these searchable online via search engines mimicking Pubmed or the PRIDE web interface. A prototype exploiting deep learning algorithms, i.e. multilayer neural networks, is presented.Circuitos de capacidades conmutadas. Análisis frecuencial por ordenador
http://hdl.handle.net/2117/87859
Circuitos de capacidades conmutadas. Análisis frecuencial por ordenador
Puerta Notario, Antonio; Miró Sans, Joan M.; Sanz Postils, Margarita
El interés fundamental de los circuitos de condensadores conmutados radica en su aplicación a la realización de filtros monolíticos y de otros bloques funcionales para su tratamiento analógico de la señal. Resulta del máximo interés disponer de métodos de análisis y programas de simulación que permitan evaluar los resultados de las diferentes técnicas de síntesis.
En este artículo se presenta un programa de simulación, basado en los métodos de análisis desarrollados por los autores, que permite la obtención de las funciones de transferencia y de la respuesta frecuencial de circuitos SC. Para su realización se requiere un soporte informático reducido, lo que, junto con la facilidad de utilización, son sus características más sobresalientes.
2016-06-09T15:57:23ZPuerta Notario, AntonioMiró Sans, Joan M.Sanz Postils, MargaritaEl interés fundamental de los circuitos de condensadores conmutados radica en su aplicación a la realización de filtros monolíticos y de otros bloques funcionales para su tratamiento analógico de la señal. Resulta del máximo interés disponer de métodos de análisis y programas de simulación que permitan evaluar los resultados de las diferentes técnicas de síntesis.
En este artículo se presenta un programa de simulación, basado en los métodos de análisis desarrollados por los autores, que permite la obtención de las funciones de transferencia y de la respuesta frecuencial de circuitos SC. Para su realización se requiere un soporte informático reducido, lo que, junto con la facilidad de utilización, son sus características más sobresalientes.Dynamic geometry based on geometric constraints
http://hdl.handle.net/2117/87511
Dynamic geometry based on geometric constraints
Freixas Boleda, Marc; Joan Arinyo, Robert; Soto Riera, Antoni; Vila Marta, Sebastià
Dynamic geometry systems are tools for geometric visualization. They allow the user to define geometric elements, establish relationships between them and explore the dynamic behavior of the remaining geometric elements when one of them is moved. The main problem in dynamic geometry systems is the ambiguity that arises from operations which lead to more than one possible solution. While the user is defining the geometric construction, he is responsible to resolve these ambiguities. However, when the user is dragging a geometric element, the system is responsible to choose the intended solution, that is, the same solution that the user would select if we could ask him again. Most dynamic geometry systems deal with this problem in such a way that the solution selection method leads to a fixed dynamic behavior of the system. This is specially annoying when this behavior is not the one the user intended. In this work we propose an architecture for dynamic geometry systems built upon a set of functional units which will allow to apply some well known results from the Geometric Constraint Solving field. A functional unit called emph{filter} will provide the user with tools to unambiguously capture the expected dynamic behavior of a given geometric problem.
2016-05-31T07:28:25ZFreixas Boleda, MarcJoan Arinyo, RobertSoto Riera, AntoniVila Marta, SebastiàDynamic geometry systems are tools for geometric visualization. They allow the user to define geometric elements, establish relationships between them and explore the dynamic behavior of the remaining geometric elements when one of them is moved. The main problem in dynamic geometry systems is the ambiguity that arises from operations which lead to more than one possible solution. While the user is defining the geometric construction, he is responsible to resolve these ambiguities. However, when the user is dragging a geometric element, the system is responsible to choose the intended solution, that is, the same solution that the user would select if we could ask him again. Most dynamic geometry systems deal with this problem in such a way that the solution selection method leads to a fixed dynamic behavior of the system. This is specially annoying when this behavior is not the one the user intended. In this work we propose an architecture for dynamic geometry systems built upon a set of functional units which will allow to apply some well known results from the Geometric Constraint Solving field. A functional unit called emph{filter} will provide the user with tools to unambiguously capture the expected dynamic behavior of a given geometric problem.Formalism for a multiresolution time series database model
http://hdl.handle.net/2117/87125
Formalism for a multiresolution time series database model
Llusa Serra, Aleix; Vila Marta, Sebastià; Escobet Canal, Teresa
We formalise a specialised database management system model for time series using a multiresolution approach. These special purpose database systems store time series lossy compressed in a space-bounded storage. Time series can be stored at multiple resolutions, using distinct attribute aggregations and keeping its temporal attribute managed in a consistent way.
The model exhibits a generic approach that facilitates its customisation to suit better the actual application requirements in a given context. The elements, the meaning of which depends on a real application, are of generic nature.
Furthermore, we consider some specific time series properties that are a challenge in the multiresolution approach. We also describe a reference implementation of the model and introduce a use case based on real data.
2016-05-17T15:17:06ZLlusa Serra, AleixVila Marta, SebastiàEscobet Canal, TeresaWe formalise a specialised database management system model for time series using a multiresolution approach. These special purpose database systems store time series lossy compressed in a space-bounded storage. Time series can be stored at multiple resolutions, using distinct attribute aggregations and keeping its temporal attribute managed in a consistent way.
The model exhibits a generic approach that facilitates its customisation to suit better the actual application requirements in a given context. The elements, the meaning of which depends on a real application, are of generic nature.
Furthermore, we consider some specific time series properties that are a challenge in the multiresolution approach. We also describe a reference implementation of the model and introduce a use case based on real data.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 presented