7,833 research outputs found
Sobre as práticas e reflexões publicitárias de Fernando Pessoa
No full textNeste texto, a autora analisa alguns trabalhos publicitários de Fernando Pessoa, bem
como algumas das suas reflexões sobre esta actividade. É dada especial atenção ao slogan
“Primeiro estranha-se. Depois entranha-se”, analisado sobre a perspectiva das funções
e propriedades deste constituinte da mensagem publicitária. Por fim, recorda-se
um recente slogan que recupera o clássico de Fernando Pessoa.
On this article, the author analyses some advertising texts created by Fernando Pessoa and
some of his thoughts about this activity. The main attention goes to the famous slogan “Primeiro
estranha-se. Depois entranha-se”, analysed through the principles of the functions
and proprieties of this element of advertisements. Finally, the author presents a recent slogan, constructed through the slogan of the Portuguese writer
Elimination of dead-time distortion using time-feedback
No full textA fully-digital algorithm to shape the spectrum of dead-time distortion in power inverters is presented. Dead-time is required to avoid short circuits of the power source by the legs of a power inverter due to the finite turn-on and turn-off times of the switches. Dead-time modifies the pulse widths of the PWM signal causing high harmonic distortion. The proposed approach is based on measuring the pulse widths at the output of the power stage, and does not require to measure the sign of the current, which is usually necessary for dead-time compensation algorithms. Furthermore, the quantization noise produced by digital PWM is also reduced, and it has a minimal computational cost.Fil: Chierchie, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Paolini, Eduardo Emilio. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto "alfredo Desages"; ArgentinaXVII Workshop on Information Processing and ControlMar del PlataArgentinaUniversidad Nacional de Mar del Plat
Volterra Models for Digital PWM and Their Inverses
No full textIn an all-digital class-D audio amplifier each signal sample is mapped into a pulse using digital pulse-width-modulation (PWM), and this intrinsically generates nonlinear distortion. This article develops discrete-time Volterra models for digital PWM. The analysis considers two types of demodulation filter, an ideal filter which provides insight into the behavior of the PWM itself, and an analog low-order demodulator filter which models the interaction of the PWM mapping with a real demodulator filter. Symmetric, trailing edge, and leading edge PWM are considered. Using the Volterra models, formulae for the inverse systems are developed. This facilitates digital precompensation of the above mentioned distortion by digitally pre-filtering the modulating signal prior to the PWM mapping. This method is first simulated and compared to pseudo-natural PWM, a well-known method for PWM distortion reduction. Moreover, the method is verified by real measurements from a physical realization of the prefilter setup using real-time digital signal processing.Fil: Chierchie, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación En Ingeniería Eléctrica; Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; ArgentinaFil: Aase, Sven Ole. University of Stavanger. Department of Electrical Engineering and Computer Science; Norueg
Real-Time Digital PWM With Zero Baseband Distortion and Low Switching Frequency
No full textA discrete-time pulse width modulator (PWM) with zero baseband distortion for arbitrary band-limited modulating signals is developed in this paper. It is based on adjusting the duty-cycles of the PWMsuch that the samples of an ideal low-pass filtered version of the PWM signal coincide with the discrete-time samples of the modulating signal. Elaborating on previous approaches in the literature, it is shown that this problem can be stated as a multidimensional inverse function approach, and therefore it can be solved using iterative methods. Starting with the duty-cycle values of a uniform PWM, the successive iterations provide slight duty-cycle corrections that, in the limit, result in zero baseband distortion even for low carrier-to-modulating frequency ratios. Aiming at a practical, real-time implementation two new results are provided. First, explicit bounds on the improvement achievable after each duty-cycle correction are derived. Second, a block processing architecture suitable for real-time implementation is proposed, and the increase of distortion caused by its use is quantified. Several examples with typical band-limited signals demonstrate the performance of the algorithm.Fil: Chierchie, Fernando. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Bahia Blanca. Instituto de Invest.en Ing.electrica; Argentina;Fil: Paolini, Eduardo Emilio. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Bahia Blanca. Instituto de Invest.en Ing.electrica; Argentina
Gain calibration and nonlinearity analysis in single photon sensitivity Skipper CCD
No full textThe Skipper CCD allows pixel measurements with sub-electron noise levels. The gain of the CCD, that relates the number of electrons to the number of analog to digital units (ADU) is almost linear but with some degree of nonlinearity.This article uses the charge quantization allowed by the SkipperCCD to estimate the gain with different strategies. Linear and quadratic models are analyzed and differential and integral nonlinearity (DNL and INL) metrics are computed. Experimental results in a range of charge between 0 and 700 electrons shows that the linear model achieves an INL of 0.8e−, while the second order model reaches an INL of 0.09e−.Fil: Lapi, Agustín Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Chierchie, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Fernández Moroni, Guillermo. Fermi National Accelerator Laboratory; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaReunión de Trabajo en Procesamiento de la Información y Control (RPIC 2021)San JuanArgentinaConsejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Automática. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Automátic
Frequency Analysis of PWM Inverters With Dead-Time for Arbitrary Modulating Signals
No full textThe effect of dead-time on the spectrum of pulsewidth modulated signals is analyzed in this paper. The study is valid for arbitrary, band-limited modulating signals, extending previous results in the literature. A simple distortion index is developed that can be used at the design stage to select dead-time or switching frequency based on maximum allowed distortion. Experimental results with various band-limited signals reveal a very good agreement between the theoretical results and the experiments.Fil: Chierchie, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación En Ingeniería Eléctrica; Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; ArgentinaFil: Stefanazzi, Leandro. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación en Ingeniería Eléctrica; Argentina. Instituto Nacional de Tecnologia Industrial; ArgentinaFil: Paolini, Eduardo Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación En Ingeniería Eléctrica; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; ArgentinaFil: Oliva, Alejandro Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación En Ingeniería Eléctrica; Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; Argentin
Low energy depositions using smart electronic readout on Skipper-CCD for lightweight Dark Matter experiment
No full textCharge-Coupled Devices (CCDs) sensors have been at the forefront of high precision and resolution imaging ever since their development. Scientific CCDs and the Skipper-CCD pushed the boundaries for sensing very weak ionizing particles, as they allow to detect without error the charge signal (even a single electron-hole pair) collected on every pixel of the detector. To obtain such precision these sensors have a slow readout time, and this has the effect of producing images with multiple particles crossing the active detection region, hindering the posterior analysis. Recently, a new electronic controller was created, the Low Threshold Acquisition or LTA. The LTA allows to perform Skipper-precision readout on selected regions of the detector. This work presents the first physics experiment utilizing the LTA ever conducted, where the spatial distribution of single electron events is studied and compared against a computational model of photon production by Cherenkov radiation, finding a close agreement between both distributions.Fil: Giardino, Lucas. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Fernández Moroni, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chierchie, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Tiffenberg, Javier Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina2022 Argentine Conference on ElectronicsArgentinaUniversidad Nacional de San Jua
Simple Real-Time Digital PWM Implementation for class-D Amplifiers With Distortion-free Baseband
No full textA real-time, digital algorithm for pulse width modulation (PWM) with distortion-free baseband is developed in this paper. The algorithm not only eliminates the intrinsic baseband distortion of digital PWM but also avoids the appearance of side-band components of the carrier in the baseband even for low switching frequencies. Previous attempts to implement digital PWM with these spectral properties required several processors due to their complexity; the proposed algorithm uses only several FIR filters and a few multiplications and additions and therefore is implemented in real time on a standard DSP. The performance of the algorithm is compared with that of uniform, double-edge PWM modulator via experimental measurements for several bandlimited modulating signals.Fil: Chierchie, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación En Ingeniería Eléctrica; Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; ArgentinaFil: Paolini, Eduardo Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación En Ingeniería Eléctrica; Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; ArgentinaFil: Stefanazzi, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación En Ingeniería Eléctrica; Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; ArgentinaFil: Oliva, Alejandro Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Investigación En Ingeniería Eléctrica; Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; Argentin
Fragments of the self: self-awareness, identity, and heteronymy in the works of Fernando Pessoa
No full textopenLa presente tesi esplora il tema dell'autocoscienza nell'opera di Fernando Pessoa, con particolare attenzione alla relazione tra identità ed eteronimia. Pessoa, attraverso la creazione dei suoi eteronimi, affronta questioni fondamentali legate alla frammentazione del sé e alla complessità dell'identità umana. L'analisi si concentra sulla natura poliedrica dell'autore, indagando come ogni eteronimo rappresenti un aspetto distinto della sua interiorità nel tentativo di comprendere e superare i limiti dell'individualità.This thesis explores the theme of self-awareness in the works of Fernando Pessoa, with a particular focus on the relashionship between identity and heteronymy. Through the creation of his heteronymys, Pessoa addresses fundamental questions related to the fragmentation of the self and the complexity of human identity. The analysis centers on the multifaceted nature of the author, investigating how each heteronym represents a distinct aspect of his inner world and an attempt to understand and transcend the limits of individuality
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Fernando Moral Iglesias writes to Dr. Hector P. Garcia about Bill Neeley, author of the book "Hispanic Patriots of the Texas Revolution." (Correspondence)
No full textFernando Moral Iglesias writes to Dr. Hector P. Garcia about Bill Neeley, author of the book "Hispanic Patriots of the Texas Revolution." Two newspaper articles about Bill Neeley are included
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