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Publications

Implementação de um Termómetro Digital Baseado em FPGA

Publication . Marques, Lucas S.; Carvalho, José Pacheco de; Reis, António

Os dispositivos de medição são largamente utilizados, desde aplicações remotas a tarefas mais precisas. A ação de medir a temperatura está embutida em diversas tarefas do nosso cotidiano, sejam elas, com baixo ou alto nível de abstração de detalhes. Este artigo apresenta a implementação de um termómetro digital, através do uso do sensor de temperatura LM35 e da placa de desenvolvimento Spartan3E da Xilinx. A análise do Processamento Digital, através de conceitos tais como Fast Fourier Transform (FFT) e de Modelagem Matemática, é veloz e eficaz. Esta análise é realizada com o auxilio das ferramentas práticas disponíveis no aplicativo de software MatLab. O Field Programmable Gate Array (FPGA) recebe o sinal digital convertido pelo Conversor Analógico Digital (ADC) e apresenta os resultados no ecrã interno. A linguagem de programação principal utilizada para o processo é o VHSIC Hardware Description Language (VHDL).

2017Conference object

Restricted access

Carrier phase synchronizers

Publication . Reis, António; Rocha, José Ferreira da; Gameiro, Atilio; Carvalho, José Pacheco de

This work studies four carrier phase synchronizers (CPS) or carrier Phase Lock Loop (CPLL). The synchronizers are based in a loop with VCO (Voltage Controlled Oscillator) that synchronizes the output feedback with the input. We consider four carrier synchronizers namely the analog, hybrid, combinational and sequential. The difference between them is in the phase comparator. The main objective is to study the synchronizers output jitter UIRMS (Unit Interval Root Mean Square) versus input SNR (Signal to Noise Ratio).

2018Conference object

Open access

Nuclear Reaction Analysis of Materials using MeV Ion Beams

Publication . Carvalho, José Pacheco de; Pacheco, Cláudia Ribeiro; Reis, Antonio

This article is about computer simulation for surface analysis through nuclear techniques, which are non-destructive. The energy analysis method is used. Energy spectra are computer simulated and compared to experimental data, giving sample composition and concentration profiles. The method is successfully applied to depth profiling of light nuclei e. g. 12C and 18O in thick targets, using deuteron and proton induced reactions, respectively. Scanning electron microscopy is used as a complementary technique, to give information about surface topography.

2017Conference object

Open access

Surface Analysis of Materials by Elastic Scattering of MeV Ions

Publication . Carvalho, José Pacheco de; Pacheco, Cláudia Ribeiro; Reis, Antonio

Abstract—This article is about computer simulation for surface analysis through nuclear techniques, which are non-destructive. The energy analysis method is used. Energy spectra are computer simulated and compared to experimental data, giving sample composition and concentration profiles. The method, using elastic scattering of (4He)+ ions, is successfully applied to depth profiling in a target containing a thin film deposited on a thick substrate and in a thick target.

2017Conference object

Open access

Low Energy Nuclear Techniques and Microscopy in Surface Analysis of Materials

Publication . Carvalho, José Pacheco de; Pacheco, Cláudia Ribeiro; Reis, António

This article is about computer simulation for surface analysis through nuclear techniques, which are mainly non-destructive. The energy analysis method, nuclear reactions and elastic scattering are used. Energy spectra are computer simulated and compared to experimental data, giving sample composition and concentration profiles. Successful applications of the method are illustrated by 18O(p,α0)15N and 12C(d,p0)13C reactions and elastic scattering of (4He)+ ions, for three types of samples. SEM microscopy is used as a complementary technique for surface imaging.

2017Conference object

Open access