Papers by Maria Liz Crespo
2019 X Southern Conference on Programmable Logic (SPL)
Zynq-7000 devices from Xilinx has gained strong popularity in the last years. Several documents a... more Zynq-7000 devices from Xilinx has gained strong popularity in the last years. Several documents and examples about interfaces usage and how to communicate the programmable logic with the processor are available, but some of them are not properly explained and in particular, the maximum throughput is not clearly specified. With this purpose, in this work a measurement method is presented and applied over the five available interfaces, considering the most used alternatives. Tests were carried on a Zybo board, but the results can be easily used to estimate the performance of others systems setups. Special hardware features and functionality are also discussed, providing a better understanding of system performance. Related papers were studied but none of them presents comparable information as to provide a fair comparison.
2021 18th International Multi-Conference on Systems, Signals & Devices (SSD)
This work reports techniques for designing an ultra-high speed dynamic latch comparator. The effe... more This work reports techniques for designing an ultra-high speed dynamic latch comparator. The effective transconductance of the cross-coupled devices consisting the latch mechanism has been improved using a compact architecture, then reducing mismatch and parasitic, increasing therefore the regeneration speed. The pre-charge step of the preamplifier has been speeded-up using an enhanced differential pair amplifier based active NMOS load. Monte-Carlo analysis of the proposed circuit implemented in 65nm CMOS process, proved that the device can achieve 20GHz sampling frequency while consuming only $78\mu \mathrm{W}$ of power from 1V supply voltage. The high-speed behavior of the circuit was guaranteed with 14.28ps time delay and 4.45mV offset voltage. The compact circuit layout occupied only $133.15 \mu m^{2}$ of active area.
2016 International Conference on Advances in Electrical, Electronic and Systems Engineering (ICAEES)
In this work we propose and analyze a possible hardware architecture for experimentation on fine-... more In this work we propose and analyze a possible hardware architecture for experimentation on fine-grained reconfigurable supercomputing based on modern Field Programmable Gate Array (FPGA) technology. It is proposed a scalable cubic array of elementary computational units which are interconnected according to a tridimensional toroidal mesh network. Each computational unit is essentially formed by an FPGA plus an onboard external RAM memory. While the adjacent units in the bulk are directly interconnected through the regular FPGA IOs; the external units at opposite faces of the cubic array are interconnected by mean of high speed serial links in order to grant homogeneous data transfer bandwidth among all topologically adjacent units. Among several relevant issues we discuss the feasibility, scalability and portability.
2019 X Southern Conference on Programmable Logic (SPL), 2019
A portable architectural design strategy is described for the implementation of reconfigurable vi... more A portable architectural design strategy is described for the implementation of reconfigurable virtual instrumentation based on programmable Systems-on-Chip integrating microprocessors and FPGA in the same physical device. The key role is played by a general purpose communication block as a means to efficiently separate the activities carried out in the microprocessor and in the FPGA. Both parts interact according to simple logic protocols by reading and writing data on the common memory resources of the communication block. The architecture of the proposed communication system can be easily implemented in practically any modern programmable System-on-Chip. With the proposed strategy, the porting of embedded software programs and associated FPGA designs among different device families and vendors is facilitated. A structured methodology is proposed for handling complex real-time systems based on these programmable Systems-on-Chip. We described a concrete communication block that has been successfully implemented and utilized for a quick implementation of a data acquisition system based on a Xilinx Zynq-7030 FPGA Mezzanine Card (FMC) and a custom FMC module with an 8-bit 500 MSPS ADC.
Advances in Computer and Electrical Engineering, 2016
Field-Programmable Gate Array (FPGA) technologies have increased in popularity in recent years du... more Field-Programmable Gate Array (FPGA) technologies have increased in popularity in recent years due to their adaptability and high computing potential. Further research in this area illustrates the potential for further advancements and applications of this useful technology. Field-Programmable Gate Array (FPGA) Technologies for High Performance Instrumentation presents experimental and theoretical research on FPGA-based design and the development of virtual scientific instrumentation that can be used by a broad segment of scientists across a variety of research fields. Focusing on crucial innovations and algorithms for signal processing, data acquisition mechanisms, FPGA-based hardware design, and parallel computing, this publication is a critical resource for researchers, development engineers, and graduate-level students.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2013
Using a 55 Fe source we characterized the spectroscopic performance of a matrix of Silicon Drift ... more Using a 55 Fe source we characterized the spectroscopic performance of a matrix of Silicon Drift Diodes (SDDs). The matrix consists of a completely depleted volume of silicon wafer subdivided into five identical hexagonal cells. The back side is composed of five implanted arrays of increasingly negatively biased concentric p þ rings. The front side, common to all five cells, is a uniformly implanted p þ entrance window. Ionizing radiation impinging the detector bulk generates electrons that drift towards small readout n þ pads placed on the back side at the center of each cell. The total sensitive area of the matrix is 135 mm 2 , the wafer thickness is 450 mm. We report on the layout of the experimental setup , as well as the spectroscopic performance measured at different temperatures and bias conditions.
Lecture Notes in Electrical Engineering
Sensors
A simplified correlation index is proposed to be used in real-time pulse shape recognition system... more A simplified correlation index is proposed to be used in real-time pulse shape recognition systems. This index is similar to the classic Pearson’s correlation coefficient, but it can be efficiently implemented in FPGA devices with far fewer logic resources and excellent performance. Numerical simulations with synthetic data and comparisons with the Pearson’s correlation show the suitability of the proposed index in applications such as the discrimination and counting of pulses with a predefined shape. Superior performance is evident in signal-to-noise ratio scenarios close to unity. FPGA implementation of Person’s method and the proposed correlation index have been successfully tested and the main results are summarized.
Physics Letters B, 2022
Based on the observation of sizeable target-transverse-spin asymmetries in single-hadron and hadr... more Based on the observation of sizeable target-transverse-spin asymmetries in single-hadron and hadron-pair production in Semi-Inclusive measurements of Deep Inelastic Scattering (SIDIS), the chiral-odd transversity quark distribution functions h q 1 are nowadays well established. Several possible channels to access these functions were originally proposed. One candidate is the measurement of the polarisation of Λ hyperons produced in SIDIS off transversely polarised nucleons, where the transverse polarisation of the struck quark might be transferred to the final-state hyperon. In this article, we present the COMPASS results on the transversityinduced polarisation of Λ andΛ hyperons produced in SIDIS off transversely polarised protons. Within the experimental uncertainties, no significant deviation from zero was observed. The results are discussed in the context of different models taking into account previous experimental results on h u 1 and h d 1 .
Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021), 2021
Discrimination of secondary particles produced in extensive air showers is needed to study the co... more Discrimination of secondary particles produced in extensive air showers is needed to study the composition of primary cosmic rays. High speed data acquisition and the increase in resources in modern FPGAs with the addition of a microprocessor in System-on-Chip (SoC) technologies allow to implement complex algorithms for digital signal analysis. Pulse shape Discrimination (PSD) can be carried out in real-time on the digital front-end of the detector; indeed online data analysis permits to save computational resources in post-processing and transmission bandwidth. We describe two methods for PSD, the first one based on artificial neural network (ANN) using the novel hls4ml package, and the other based on a correlation approach using finite impulse response (FIR) filters. Both methods were implemented and tested on Xilinx FPGA SoC devices ZU9EG Zynq Ultrascale+ and XC7Z020 Zynq. Data from a Water Cherenkov Detector (WCD) were acquired with a 500 Mhz, 8-bit high speed analog-to-digital converter acquisition system. Experimental results obtained with both methods are presented along with timing, accuracy and resources utilization analysis.
Proceedings of the 1999 Congress on Evolutionary Computation-CEC99 (Cat. No. 99TH8406)
In this paper, FCDT (Fuzzy Controllers Development Tool) is presented. FCDT is a software tool th... more In this paper, FCDT (Fuzzy Controllers Development Tool) is presented. FCDT is a software tool that provides a graphical environment to develop and test fuzzy controllers. Complete fuzzy controllers can be defined, enhanced manually and tested on target systems. FCDT implements a neural network based algorithm that can be used to enhance automatically the fuzzy controllers and an evolutionary algorithm that allows the design of the fuzzy rule base and the number and shape of membership functions for the output variables automatically. FCDT, documentation, examples and its source code is made available in the hope that it will be useful to the research community.
Physics Letters B, 2020
Thep over p multiplicity ratio is measured in deep-inelastic scattering for the first time using ... more Thep over p multiplicity ratio is measured in deep-inelastic scattering for the first time using (anti-) protons carrying a large fraction of the virtual-photon energy, z > 0.5. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar 6 LiD target. The regime of deep-inelastic scattering is ensured by requiring Q 2 > 1 (GeV/c) 2 for the photon virtuality and W > 5 GeV/c 2 for the invariant mass of the produced hadronic system. The range in Bjorken-x is restricted to 0.01 < x < 0.40. Protons and antiprotons are identified in the momentum range 20 ÷ 60 GeV/c. In the whole studied z-region, thep over p multiplicity ratio is found to be below the lower limit expected from calculations based on leading-order perturbative Quantum Chromodynamics (pQCD). Extending our earlier analysis of the K − over K + multiplicity ratio by including now events with larger virtual-photon energies, this ratio becomes closer to the expectation of next-to-leading order pQCD. The results of both analyses strengthen our earlier conclusion that the phase space available for hadronisation should be taken into account in the pQCD formalism.
IEEE Access, 2020
The increased popularity of investigations and exploits in the fields of neurological rehabilitat... more The increased popularity of investigations and exploits in the fields of neurological rehabilitation, human emotion recognition, and other relevant brain-computer interfaces demand the need for flexible electrophysiology data acquisition systems. Such systems often require to be multi-modal and multi-channel capable of acquiring and processing several different types of physiological signals simultaneously in realtime. Developments of modular and scalable electrophysiological data acquisition systems for experimental research enhance understanding and progress in the field. To contribute to such an endeavor, we present an open-source hardware project called High-Channel Count Electrophysiology or HiCCE, targeting to produce an easily-adaptable, cost-effective, and affordable electrophysiological acquisition system as an alternative solution for mostly available commercial tools and the current state of the art in the field. In this paper, we describe the design and validation of the entire chain of the HiCCE-128 electrophysiological data acquisition system. The system comprises of 128 independent channels capable of acquiring signal at 31.25 kHz, with 16 effective bits per channel with a measured noise level of about 3 µV. The reliability and feasibility of the implemented system have been confirmed through a series of tests and real-world applications. The modular design methodology based on the FPGA Mezzanine Card (FMC) standard allows the connection of the HiCCE-128 board to programmable system-on-chip carrier devices through the high-speed FMC link. The implemented architecture enables end users to add various high-response electrophysiological signal processing techniques in the field programmable gate arrays (FPGA) part of the system on chip (SoC) device on each channel in parallel according to application specification. INDEX TERMS Data acquisition, electrophysiology, field programmable gate arrays (FPGA), multichannel, open source hardware, system on chip (SoC).
Scientific Reports, 2020
A capacitive electromyography (cEMG) biomedical sensor measures the EMG signal from human body th... more A capacitive electromyography (cEMG) biomedical sensor measures the EMG signal from human body through capacitive coupling methodology. It has the flexibility to be insulated by different types of materials. Each type of insulator will yield a unique skin–electrode capacitance which determine the performance of a cEMG biomedical sensor. Most of the insulator being explored are solid and non-breathable which cause perspiration in a long-term EMG measurement process. This research aims to explore the porous medical bandages such as micropore, gauze, and crepe bandage to be used as an insulator of a cEMG biomedical sensor. These materials are breathable and hypoallergenic. Their unique properties and characteristics have been reviewed respectively. A 50 Hz digital notch filter was developed and implemented in the EMG measurement system design to further enhance the performance of these porous medical bandage insulated cEMG biomedical sensors. A series of experimental verifications such...
Journal of Physics: Conference Series, 2020
Experiments at the future Electron Ion Collider require excellent hadron identification in a broa... more Experiments at the future Electron Ion Collider require excellent hadron identification in a broad momentum range, in harsh conditions. A RICH capable to fulfill the PID requirements of the EIC could use MPGD-based photon detectors with solid photocathodes for covering large surfaces at affordable cost, providing good effciency, high resolution and compatibility with magnetic field. Photon detectors realized by coupling THGEMs and Micromegas have been successfully operated at the RICH-1 detector of the COMPASS Experiment at CERN since 2016. A similar technology could be envisaged for an EIC RICH, provided a large improvement in the photon position resolution is achieved. An R&D effort in this direction is ongoing at INFN Trieste. Few prototypes with smaller pixel size (down to 3 mm x 3 mm) have been built and tested in the laboratory with X-Ray and UV LED light sources. A modular mini-pad detector prototype has also been tested at the CERN SPS H4 beamline. New data acquisition and a...
Jurnal Teknologi, 2019
Digital controlled oscillator (DCO) is becoming an attractive replacement over the voltage contro... more Digital controlled oscillator (DCO) is becoming an attractive replacement over the voltage control oscillator (VCO) with the advances of digital intensive research on all-digital phase locked-loop (ADPLL) in complementary metal-oxide semiconductor (CMOS) process technology. This paper presents a review of various CMOS DCO schemes implemented in ADPLL and relationship between the DCO parameters with ADPLL performance. The DCO architecture evaluated through its power consumption, speed, chip area, frequency range, supply voltage, portability and resolution. It can be concluded that even though there are various schemes of DCO that have been implemented for ADPLL, the selection of the DCO is frequently based on the ADPLL applications and the complexity of the scheme. The demand for the low power dissipation and high resolution DCO in CMOS technology shall remain a challenging and active area of research for years to come. Thus, this review shall work as a guideline for the researchers ...
Physics Letters B, 2018
Search for muoproduction of X(3872) at COMPASS and indication of a new state X(3872) The COMPASS ... more Search for muoproduction of X(3872) at COMPASS and indication of a new state X(3872) The COMPASS Collaboration
Physical Review Letters, 2017
X-Ray Spectrometry, 2017
In spite of the constant technological improvements in the field of detector development, X-ray f... more In spite of the constant technological improvements in the field of detector development, X-ray fluorescence (XRF) in the soft X-ray regime remains a challenge. The low intrinsic fluorescence yield for energies below 2 keV indeed renders the applicability of low-energy XRF still difficult. Here, we report on a new multi-element multi-tile detection system currently under development, designed to be integrated into a soft X-ray microscopy end station. The system will be installed at the TwinMic beamline of Elettra synchrotron (Trieste, Italy) in order to increase the detected count rate by up to an order of magnitude. The new architecture is very versatile and can be adapted to any XRF experimental setup. Even though the first results of the previous version of such a multi-element system were encouraging, several issues still needed to be addressed. The system described here represents a further step in the detector evolution. It is based on four trapezoidal-shaped monolithic silicon drift detector tiles (matrices) with six hexagonal elements each equipped with a custom ultra-low noise application-specific integrated circuit readout. The whole signal processing chain has been improved leading to an overall increase in performances, namely, in terms of energy resolution and acquisition rates. The design and development of this new detection system will be described, and recent results obtained at the TwinMic beamline at Elettra will be presented. Future perspectives and improvements will also be discussed.
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Papers by Maria Liz Crespo
Field-Programmable Gate Array (FPGA) Technologies for High Performance Instrumentation presents experimental and theoretical research on FPGA-based design and the development of virtual scientific instrumentation that can be used by a broad segment of scientists across a variety of research fields. Focusing on crucial innovations and algorithms for signal processing, data acquisition mechanisms, FPGA-based hardware design, and parallel computing, this publication is a critical resource for researchers, development engineers, and graduate-level students.