CIRCUIT  Grup de Recerca en Circuits i Sistemes de Comunicació
http://hdl.handle.net/2117/3801
20160214T12:44:45Z

Design and performance comparison of a superregenerative MPSK transceiver
http://hdl.handle.net/2117/81819
Design and performance comparison of a superregenerative MPSK transceiver
Bonet Dalmau, Jordi; López Riera, Alexis; Palà Schönwälder, Pere; Moncunill Geniz, Francesc Xavier; Babí Oller, Albert
In this paper we present a superregenerative transceiver able to switch among BPSK, QPSK and 8PSK modulations.
An HFband proofofconcept transceiver is implemented on an FPGA with a minimum of analog circuitry. The desire of making fair comparisons between BER figures rises a problem of clock frequency selection which is finally solved without consuming extra resources.
20160121T16:02:31Z
Bonet Dalmau, Jordi
López Riera, Alexis
Palà Schönwälder, Pere
Moncunill Geniz, Francesc Xavier
Babí Oller, Albert
In this paper we present a superregenerative transceiver able to switch among BPSK, QPSK and 8PSK modulations.
An HFband proofofconcept transceiver is implemented on an FPGA with a minimum of analog circuitry. The desire of making fair comparisons between BER figures rises a problem of clock frequency selection which is finally solved without consuming extra resources.

Single cycle and transient force measurements in dynamic atomic force microscopy
http://hdl.handle.net/2117/78946
Single cycle and transient force measurements in dynamic atomic force microscopy
Gadelrab, Karim Raafat; Santos, Sergio; Font Teixidó, Josep; Chiesa, Matteo
The monitoring of the deflection of a microcantilever, as the end of a sharp probe mounted at its end, i.e. the tip, interacts with a surface, forms the foundation of atomic force microscopy AFM. In a nutshell, developments in the field are driven by the requirement of obtaining ever increasing throughput and sensitivity, and enhancing the versatility of the instrument to simultaneously map the topography and quantify nanoscale processes and properties. In the most common dynamic mode of operation, the motion of the driven cantilever is monitored at a single point on its longitudinal axis. Here, we show that from this single point a waveform is obtained that contains all the details about conservative and dissipative interactions. Then a formalism that accounts for multiple arbitrary flexural modes is developed for an indirectly driven cantilever. The formalism is shown to allow recovery of the details of the interaction even in the presence of complex and relevant hysteretic forces when the cantilever oscillates in the steady state. In a different approach, we develop a formalism that monitors the wave profile of the cantilever, i.e. the waveform at five different points on its longitudinal axis. With this formalism the interaction can be reconstructed during a single oscillation cycle even in the transient state of oscillation. Finally, we discuss the potential and advantages of the proposed methods and future technical challenges. Other standard and state of the art techniques and methods are also discussed and compared with the ones presented here. This work should also provide insight into the current high throughputhigh sensitivity developments dealing with multifrequency dynamic AFM where information is recovered from multiple eigenmodes. © 2013 The Royal Society of Chemistry.
20151109T17:31:13Z
Gadelrab, Karim Raafat
Santos, Sergio
Font Teixidó, Josep
Chiesa, Matteo
The monitoring of the deflection of a microcantilever, as the end of a sharp probe mounted at its end, i.e. the tip, interacts with a surface, forms the foundation of atomic force microscopy AFM. In a nutshell, developments in the field are driven by the requirement of obtaining ever increasing throughput and sensitivity, and enhancing the versatility of the instrument to simultaneously map the topography and quantify nanoscale processes and properties. In the most common dynamic mode of operation, the motion of the driven cantilever is monitored at a single point on its longitudinal axis. Here, we show that from this single point a waveform is obtained that contains all the details about conservative and dissipative interactions. Then a formalism that accounts for multiple arbitrary flexural modes is developed for an indirectly driven cantilever. The formalism is shown to allow recovery of the details of the interaction even in the presence of complex and relevant hysteretic forces when the cantilever oscillates in the steady state. In a different approach, we develop a formalism that monitors the wave profile of the cantilever, i.e. the waveform at five different points on its longitudinal axis. With this formalism the interaction can be reconstructed during a single oscillation cycle even in the transient state of oscillation. Finally, we discuss the potential and advantages of the proposed methods and future technical challenges. Other standard and state of the art techniques and methods are also discussed and compared with the ones presented here. This work should also provide insight into the current high throughputhigh sensitivity developments dealing with multifrequency dynamic AFM where information is recovered from multiple eigenmodes. © 2013 The Royal Society of Chemistry.

Establishing nanoscale heterogeneity with nanoscale force measurements
http://hdl.handle.net/2117/78535
Establishing nanoscale heterogeneity with nanoscale force measurements
Chang, YunHsiang, YunHsiang; Olukan, Tuza; Lai, ChiaYun; Santos, Sergio; Lin, TzeYu; Apostoleris, Harry; Font Teixidó, Josep; Barcons Xixons, Víctor; Chiesa, Matteo
Establishing the presence or absence of nanoscale compositional heterogeneity with nanoscale resolution is becoming instrumental for the development of many fields of science. Force versus distance measurements and parameters directly or indirectly derived from these profiles can be potentially employed for this purpose with sophisticated instruments such as the atomic force microscope (AFM). On the other hand, standards are necessary to reproducibly and conclusively support hypothesis from experimental data and these standards are still emerging. Here, we define a set of standards for providing data originating from atomic force measurements to be employed to compare between sample properties, parameters, or, more generally, compositional heterogeneity. We show that reporting the mean and standard deviation only might lead to inconsistent conclusions. The fundamental principle behind our investigation deals with the very definition of reproducibility and repeatability in terms of accuracy and precision, and we establish general criteria to ensure that these hold without the need of restricting assumptions.
20151029T19:05:50Z
Chang, YunHsiang, YunHsiang
Olukan, Tuza
Lai, ChiaYun
Santos, Sergio
Lin, TzeYu
Apostoleris, Harry
Font Teixidó, Josep
Barcons Xixons, Víctor
Chiesa, Matteo
Establishing the presence or absence of nanoscale compositional heterogeneity with nanoscale resolution is becoming instrumental for the development of many fields of science. Force versus distance measurements and parameters directly or indirectly derived from these profiles can be potentially employed for this purpose with sophisticated instruments such as the atomic force microscope (AFM). On the other hand, standards are necessary to reproducibly and conclusively support hypothesis from experimental data and these standards are still emerging. Here, we define a set of standards for providing data originating from atomic force measurements to be employed to compare between sample properties, parameters, or, more generally, compositional heterogeneity. We show that reporting the mean and standard deviation only might lead to inconsistent conclusions. The fundamental principle behind our investigation deals with the very definition of reproducibility and repeatability in terms of accuracy and precision, and we establish general criteria to ensure that these hold without the need of restricting assumptions.

Problemes de modelització amb UML. Programació orientada a objectes
http://hdl.handle.net/2117/78444
Problemes de modelització amb UML. Programació orientada a objectes
Brínquez Jiménez, Jordi; Dodero Beardo, Juan Manuel; Tarres Puertas, Marta Isabel
20151028T15:20:47Z
Brínquez Jiménez, Jordi
Dodero Beardo, Juan Manuel
Tarres Puertas, Marta Isabel

El llenguatge Java
http://hdl.handle.net/2117/78433
El llenguatge Java
Tarres Puertas, Marta Isabel
20151028T14:24:13Z
Tarres Puertas, Marta Isabel

Geometric constraint graphs decomposition based on computing graph circuits
http://hdl.handle.net/2117/78430
Geometric constraint graphs decomposition based on computing graph circuits
Joan Arinyo, Robert; Tarres Puertas, Marta Isabel; Vila Marta, Sebastià
Geometric constraint solving is a growing field which plays a paramount role in industrial applications and that is deeply rooted in automated deduction in geometry. In this work we report on an algorithm to solve geometric
constraintbased problems by decomposing biconnected graphs. The algorithm is based on recursively splitting the graph through sets with three vertices located on fundamental circuits of the graph. Preliminary practical experiments suggest that the algorithm runtime is at worst quadratic with the total number of vertices in the graph.
20151028T14:11:03Z
Joan Arinyo, Robert
Tarres Puertas, Marta Isabel
Vila Marta, Sebastià
Geometric constraint solving is a growing field which plays a paramount role in industrial applications and that is deeply rooted in automated deduction in geometry. In this work we report on an algorithm to solve geometric
constraintbased problems by decomposing biconnected graphs. The algorithm is based on recursively splitting the graph through sets with three vertices located on fundamental circuits of the graph. Preliminary practical experiments suggest that the algorithm runtime is at worst quadratic with the total number of vertices in the graph.

Periodicity in bimodal atomic force microscopy
http://hdl.handle.net/2117/76907
Periodicity in bimodal atomic force microscopy
Lai, ChiaYun; Barcons Xixons, Víctor; Santos, Sergio; Chiesa, Matteo
Periodicity is fundamental for quantification and the application of conservation principles of many important systems. Here, we discuss periodicity in the context of bimodal atomic force microscopy (AFM). The relationship between the excited frequencies is shown to affect and control both experimental observables and the main expressions quantified via these observables, i.e., virial and energy transfer expressions, which form the basis of the bimodal AFM theory. The presence of a fundamental frequency further simplifies the theory and leads to close form solutions. Predictions are verified via numerical integration of the equation of motion and experimentally on a mica surface.
20150917T14:41:26Z
Lai, ChiaYun
Barcons Xixons, Víctor
Santos, Sergio
Chiesa, Matteo
Periodicity is fundamental for quantification and the application of conservation principles of many important systems. Here, we discuss periodicity in the context of bimodal atomic force microscopy (AFM). The relationship between the excited frequencies is shown to affect and control both experimental observables and the main expressions quantified via these observables, i.e., virial and energy transfer expressions, which form the basis of the bimodal AFM theory. The presence of a fundamental frequency further simplifies the theory and leads to close form solutions. Predictions are verified via numerical integration of the equation of motion and experimentally on a mica surface.

Superregenerative reception of narrowband FSK modulations
http://hdl.handle.net/2117/27802
Superregenerative reception of narrowband FSK modulations
Palà Schönwälder, Pere; Bonet Dalmau, Jordi; López Riera, Alexis; Moncunill Geniz, Francesc Xavier; Águila López, Francisco del; Giralt Mas, Ma. Rosa
In this paper we investigate the possibilities of narrowband FSK detection using a superregenerative (SR) receiver. Previous SR FM demodulation techniques rely on detecting the amplitude variations caused by the different frequencies involved in FSK modulation. However, this requires relatively high frequency deviations because the frequency response of SR receivers is not very selective. In this paper we take a different approach, exploiting the distinct phase trajectories of FSK modulations resulting from the transmitted data. The wellknown fact that the SR oscillator response preserves the phase information of the received signal is successfully exploited to allow the detection of several FSK modulations. These include the special case of MSK, opening the way to applying the SR principle to several communication standards, such as IEEE 802.15.4. The key ideas for symbol synchronization are also presented. Experimental results on a 10 kbit/s proofofconcept MSK receiver, achieving a sensitivity better than 114 dBm in the HF band, validate the proposed approach.
20150506T17:58:45Z
Palà Schönwälder, Pere
Bonet Dalmau, Jordi
López Riera, Alexis
Moncunill Geniz, Francesc Xavier
Águila López, Francisco del
Giralt Mas, Ma. Rosa
In this paper we investigate the possibilities of narrowband FSK detection using a superregenerative (SR) receiver. Previous SR FM demodulation techniques rely on detecting the amplitude variations caused by the different frequencies involved in FSK modulation. However, this requires relatively high frequency deviations because the frequency response of SR receivers is not very selective. In this paper we take a different approach, exploiting the distinct phase trajectories of FSK modulations resulting from the transmitted data. The wellknown fact that the SR oscillator response preserves the phase information of the received signal is successfully exploited to allow the detection of several FSK modulations. These include the special case of MSK, opening the way to applying the SR principle to several communication standards, such as IEEE 802.15.4. The key ideas for symbol synchronization are also presented. Experimental results on a 10 kbit/s proofofconcept MSK receiver, achieving a sensitivity better than 114 dBm in the HF band, validate the proposed approach.

Forward backward asymmetries of lepton pairs in events with a large transverse momentum jet at hadron colliders
http://hdl.handle.net/2117/24587
Forward backward asymmetries of lepton pairs in events with a large transverse momentum jet at hadron colliders
Águila López, Francisco del; Ametller Congost, Lluís; Talavera Sánchez, Pedro
We discuss forwardbackward charge asymmetries for leptonpair production in association with a largetransversemomentum jet at hadron colliders. The lepton charge asymmetry relative to the jet direction AjFB gives a new determination of the effective weak mixing angle sin2lept
eff M2 Z with a statistical precision after cuts of 10 3 (8 10 3) at LHC (Tevatron). This is to be compared with the current uncertainty at LEP and SLD from the asymmetries alone, 2 10 4. The identification of b jets
also allows for the measurement of the bottomquark–Z asymmetry AbFB at hadron colliders, the resulting statistical precision for sin2lept eff M2
Z being 9 10 4 (2 10 2 at Tevatron), also lower than the reported precision at e+ e colliders, 3 10 4.
20141106T19:13:03Z
Águila López, Francisco del
Ametller Congost, Lluís
Talavera Sánchez, Pedro
We discuss forwardbackward charge asymmetries for leptonpair production in association with a largetransversemomentum jet at hadron colliders. The lepton charge asymmetry relative to the jet direction AjFB gives a new determination of the effective weak mixing angle sin2lept
eff M2 Z with a statistical precision after cuts of 10 3 (8 10 3) at LHC (Tevatron). This is to be compared with the current uncertainty at LEP and SLD from the asymmetries alone, 2 10 4. The identification of b jets
also allows for the measurement of the bottomquark–Z asymmetry AbFB at hadron colliders, the resulting statistical precision for sin2lept eff M2
Z being 9 10 4 (2 10 2 at Tevatron), also lower than the reported precision at e+ e colliders, 3 10 4.

A low inband radiation superregenerative oscillator
http://hdl.handle.net/2117/24580
A low inband radiation superregenerative oscillator
Palà Schönwälder, Pere; Bonet Dalmau, Jordi; Moncunill Geniz, Francesc Xavier; Águila López, Francisco del; Giralt Mas, Ma. Rosa
This brief describes a superregenerative (SR) voltagecontrolled oscillator as a building block for SR receivers where most of the oscillator spectrum components are outside the reception frequency band. This allows overcoming one of the main drawbacks of SR receivers, i.e., the potential interference to nearby receivers operating at the same frequency due to oscillator reradiation. We perform a qualitative analysis of the solution of the circuit equations, describe the most relevant parameters for design, and provide some numerical simulation results. Experimental results on a proofofconcept implementation validating the described principle and a discussion of the observed behavior are provided.
20141106T18:06:44Z
Palà Schönwälder, Pere
Bonet Dalmau, Jordi
Moncunill Geniz, Francesc Xavier
Águila López, Francisco del
Giralt Mas, Ma. Rosa
This brief describes a superregenerative (SR) voltagecontrolled oscillator as a building block for SR receivers where most of the oscillator spectrum components are outside the reception frequency band. This allows overcoming one of the main drawbacks of SR receivers, i.e., the potential interference to nearby receivers operating at the same frequency due to oscillator reradiation. We perform a qualitative analysis of the solution of the circuit equations, describe the most relevant parameters for design, and provide some numerical simulation results. Experimental results on a proofofconcept implementation validating the described principle and a discussion of the observed behavior are provided.