Optical Signal Processing
Mostrando 13-24 de 32 artigos, teses e dissertações.
-
13. Study and compensation of bias drift, scale factor stability and linearity of a conditioning and sign processing circuit of an interferometric fiber optic gyroscope / Estudo e compensação da deriva termica, estabilidade do fator de escala e lineariazação de um circuito de condicionamento e processamento de sinais de girometro interferometrico a fibra optica
Fiber Optic gyroscopes are an important part of inertial navigation systems. To meet the necessary specifications required for application in inertial systems, it is mandatory that the electronic Sagnac demodulator uses state of the art devices. The proposal of this work is to study and develop a technique to correct all together for the nonlinearities, the
Publicado em: 2009
-
14. Processamento de imagens na analise dinamica de risers de produção de petroleo com modelo de escala reduzida em ambiente de laboratorio / Image processing in dynamic analysis of risers of petroleum production with reduced-scale model in a laboratory environment
This work develops a technique for recording and processing the signals of movement of a reduced oil producing riser, with the use of optical cameras. It is based on the use of targets attached to the riser model, and the detection of its position in space. The application of the proposed technique is based on the sequence of images captured from the target,
Publicado em: 2008
-
15. Controle automatico eletronico de ganho com supressão de transientes aplicado a EDFAs em redes opticas WDM / Eletronic automatic gain control with transient suppresion applied over WDM optical networks
IIn WDM optical communication systems erbium doped fiber amplifiers (EDFA) have an essential function, enabling amplification of simultaneous channels independently of transmit rate. The majority of current WDM systems use point to point configuration operating with a fixed number of channels over the optical link. However, the new generation optical systems
Publicado em: 2008
-
16. Monitoring fails in tubes using signals digital processing / Sistema de monitoramento de falhas em tubulações por meio de processamento digital de sinais
Natural gas has hazardous contaminants that, besides being corrosive, compromise the quality for the consumption. For in such a way the present residual water condensation in the gas can start a local corrosive process, which could cause damage to the structure of the gas ducts. Due to the great length of a gas duct, corrosive components decrease its quality
Publicado em: 2008
-
17. Acopladores direcionais de fibras Ãpticas com perfis de dispersÃo / Directional optic staple dispersion profile fiber(DPF)
We present a numerical investigation of the propagation and the switching of fundamental solitons in a two-core nonlinear fiber coupler constructed with Dispersion Profile Fiber (DPF). We have shown that appropriate shaping of the DPF profile is quite effective to recover, almost completely, the original switching behavior associated to the lossless situatio
Publicado em: 2007
-
18. Analysis of optical CDMA systems / Análise de sistemas CDMA ópticos
The evolution of optical networks verified in the last few years has been characterized by the search for better bandwidth utilization efficiency. The successful implementation of practical code division for multiple access techniques (CDMA) in mobile communications systems has stimulated new investigations on this topic, particularly in the optical domain (
Publicado em: 2006
-
19. Medição e simulação de conversor em comprimento de onda com amplificador optico a semicondutor / Measurements and simulations of wavelenght converter based on semiconductor optical amplifier
The use of wavelenght-division multiplex (WDM) optical networks is a solution for the data-rate increasing in telecommunications systems. For a good performance of such networks, the use of wavelength converter based on semiconductor optical amplifier is important, since this one allows all-optical signal processing, as well as more flexibility in the spectr
Publicado em: 2006
-
20. Restauração de imagens de microscopia confocal utilizando técnicas POCS.
Computer Optical Sectioning Microscopy (COSM) is widely used in morphological studies of cellular structures. COSM appears as a great challenge to digital image processing, because the large size of the three-dimensional files. The major problem in COSM is the blurring, which practically turn the image unusable without the use of digital image processing tec
Publicado em: 2005
-
21. Differentiation of autonomic reflex control begins with cellular mechanisms at the first synapse within the nucleus tractus solitarius
Visceral afferents send information via cranial nerves to the nucleus tractus solitarius (NTS). The NTS is the initial step of information processing that culminates in homeostatic reflex responses. Recent evidence suggests that strong afferent synaptic responses in the NTS are most often modulated by depression and this forms a basic principle of central in
Brazilian Journal of Medical and Biological Research. Publicado em: 2004-04
-
22. Automated control of light beam scanners / Controle automatizado para scanners de luz
The work presents a method for automatically positioning of the light beam scanners. A strategy for synchronizing their positions based on the audio signals is also developed All control modes developed are incorporated into a managing system software. The controlling process requires the construction of a digital data interface to the hardware on the basis
Publicado em: 2004
-
23. Modelagem de estruturas fotonicas por elementos finitos 2D no dominio do tempo
This thesis shows an efficient and powerful numerical metodology to analyze photonic structures in cartesian and cylindrical coordinates and they are supposed to have arbitrary refractive indexes. The algorithms, based on the finite element method, were developed in time and frequency domains. The first algorithm is based on the wave propagation method (WPM)
Publicado em: 2003
-
24. Nova tecnica de processamento de sinais no dominio do tempo de giroscopios interferometricos de Sagnac a fibra optica
This work focuses on the study of a new time domain signal processing technique of Sagnac interferometric fiber optic gyroscopes. The technique consists in demodulating the output signal of the interferometer to obtain the rotation rate W and to monitor both the optical phase modulation depth m f and the incident power level 0 P , by measuring the dc value a
Publicado em: 2001