Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-17T12:37:21Z No. of bitstreams: 1 diogofernandes.pdf: 2723080 bytes, checksum: 27ac16e618618f1cb4c4dc6394956f80 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-06-28T14:08:15Z (GMT) No. of bitstreams: 1 diogofernandes.pdf: 2723080 bytes, checksum: 27ac16e618618f1cb4c4dc6394956f80 (MD5) / Made available in DSpace on 2016-06-28T14:08:15Z (GMT). No. of bitstreams: 1 diogofernandes.pdf: 2723080 bytes, checksum: 27ac16e618618f1cb4c4dc6394956f80 (MD5) Previous issue date: 2015-08-31 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / Este trabalho tem como objetivo apresentar técnicas com complexidade computacional reduzida para implementação em hardware do modulador de amplitude em quadratura M-ária (M-ary quadrature amplitude modulation - M-QAM) de elevada ordem, que pode ser viável para sistemas banda larga. As técnicas propostas abrangem as constelações M-QAM quadradas e cruzadas (número par e ímpar de bits), a regra de decisão abrupta (hard decison rule), derivação de constelações M-QAM de baixa ordem das de elevada ordem. A análise de desempenho em termos de taxa de bits errados (bit error rate - BER) é realizada quando os símbolos M-QAM são corrompidos por ruído Gaussiano branco aditivo (additive white Gaussian noise - AWGN) e ruído Gaussiano impulsivo aditivo (additive impulsive Gaussian noise - AIGN). Os resultados de desempenho da taxa de bits errados mostram que a perda de desempenho das técnicas propostas é, em média, inferior a 1 dB, o que é um resultado surpreendente. Além disso, a implementação das técnicas propostas em arranjo de portas programáveis em campo (field programmable gate array - FPGA) é descrita e analisada. Os resultados obtidos com as implementações em dispositivo FPGA mostram que as técnicas propostas podem reduzir consideravelmente a utilização de recursos de hardware se comparadas com as técnicas presentes na literatura. Uma melhoria notável em termos de redução da utilização de recursos de hardware é conseguida através da utilização da técnica de modulação M-QAM genérica em comparação com a técnica de regra de decisão heurística (heuristic decision rule - HDR) aprimorada e uma técnica previamente concebida, a tà c cnica HDR. Com base nas análises apresentadas, a técnica HDR aprimorada é menos complexa do que a técnica HDR. Finalmente, os resultados numéricos mostram que a técnica de modulação M-QAM genérica pode ser oito vezes mais rápida do que as outras duas técnicas apresentadas, quando um grande número de símbolos M-QAM (p. ex., > 1000) são transmitidos consecutivamente. / This work aims at introducing techniques with reduced computational complexity for hardware implementation of high order M-ary quadrature amplitude modulation (MQAM) which may be feasible for broadband communication systems. The proposed techniques cover both square and cross M-QAM constellations (even and odd number of bits), hard decision rule, derivation of low-order M-QAM constellations from high order ones. Performance analyses, in terms of bit error rate (BER) is carried out when the M-QAM symbols are corrupted by either additive white Gaussian noise (AWGN) or additive impulsive Gaussian noise (AIGN). The bit error rate performance results show that the performance loss of the proposed techniques is, on average, less than 1 dB, which is a remarkable result. Additionally, the implementation of the proposed techniques in field programmable gate array (FPGA) device is described and outlined. The results based on FPGA show that the proposed techniques can considerably reduce hardware resource utilization. A remarkable improvement in terms of hardware resource utilization reduction is achieved by using the generic M-QAM technique in comparison with the enhanced heuristic decision rule (HDR) technique and a previously designed technique, the HDR technique. Based on the analyses performed, the enhanced HDR technique is less complex than the HDR technique. Finally, the numerical results show that the generic M-QAM technique can be eight times faster than the other two techniques when a large number of M-QAM symbols (e.g., > 1000) are consecutively transmitted.

Viele Probleme der Riss- und Bruchmechanik sowie der mathematischen Physik lassen sich auf Lösungen von singulären Integralgleichungen über einem Intervall zurückführen. Diese Gleichungen setzen sich im Wesentlichen aus dem Cauchy'schen singulären Integraloperator und zusätzlichen Integraloperatoren mit festen Singularitäten in den jeweiligen Kernen zusammen. Zur numerischen Lösung solcher Gleichungen werden polynomiale Kollokations-Quadraturverfahren betrachet. Als Ansatzfunktionen und Kollokationspunkte werden dabei gewichtete Polynome und Tschebyscheff-Knoten gewählt. Die Gewichte sind so gewählt, dass diese das asymptotische Verhalten der Lösung in den Randpunkten widerspiegeln. Mit Hilfe von C*-Algebra Techniken, werden in dieser Arbeit notwendige und hinreichende Bedingungen für die Stabilität der Kollokations-Quadraturverfahren angegeben. Die theoretischen Resultate werden dabei durch numerische Berechnungen anhand des Problems der angerissenen Halbebene und des angerissenen Loches überprüft.

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This thesis deals with ultrasound blood flow meter design with emphasis on practical implementation of such device. This medical device is used in ultrasound diagnostic, especially for measuring direction and velocity of blood flow in superficial vessels. This thesis contains consecutive design including description of individual function blocks. Documents for making double-sided printed circuit are included as well.

This thesis deals with analysis of electric drive parts from hybrid electric vehicle, namely interior permanent magnet synchronous motor and inverter with control. First part describes a basic theory. Further, motor and inverter computer models are shown, specified simulations are performed on this models. Results are compared with values measured on real machines from accessible literary sources.

Dissertation thesis is focused on real digital signal processing by quadrature mirror digital filter banks. In the first part a dual channel quadrature mirror digital filter bank is described briefly. Mainly transfer functions for distorted subband signals are described. In the next part generalized sigma-delta modulator and its linear model are described. Subsequently the generalized sigma-delta modulator is used in decomposition part of quadrature mirror digital filter bank. Designed structure is analyzed. Two design method of transfer functions are designed for the structure on the basis of analysis results. The first method is suitable for hand-made design by intuitive distribution of zeros and poles. The second method is more suitable for computer design. It is iterative method based on correlation. Transfer functions for quadrature mirror digital filter bank with sigma-delta modulators design examples are also part of thesis. Application of designed structure of quadrature mirror digital filter bank can lead to bigger compression ration in lossy data compression.

This master‘s thesis deals with design and realisation of a control module for automated measurements of the modern contactless inductive position sensors by a mechanical rotational system consisting of a DC motor and an incremental quadrature encoder. The thesis presents methods of driving DC motor and recording of measured data by a microcontroller. The thesis presents a communication protocol between the control module and personal computer via USB interface. A part of this thesis is also to develop a control software and firmware, including the measurement and evaluation of properties of the control module.

This thesis deals with modern methods of a lossy still image and video compression. Wavelet transformation and SPIHT algorithm also belong to these methods. In second half of this thesis, a videocodec is implemented based on acquired knowledge. This codec uses Daubechies wavelets to analyse an image. Afterwards there is a modified SPIHT algorithm applied on gained coefficients. A lot of effort was put in order to optimize this computation. It is possible to use the created codec in Video for Windows, DirectShow and FFmpeg multimedia frameworks. At the end of this thesis, commonly used codecs are compared with newly created one.

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An experimental investigation of an M level (M = 16, 64 and 256) Quadrature Amplitude Modulation (QAM) transmission system suitable for video transmission is presented. The communication system is based on layered video coding and unequal error protection to make the video bitstream robust to channel errors. An implementation is described in which H.264 video is protected unequally by partitioning the compressed data into two layers of different visual importance. The partition scheme is based on a separation of the group of pictures (GoP) in the intra-coded frame (I-frame) and predictive coded frame (P frame). This partition scheme is then applied to split the H.264-coded video bitstream and is suitable for Constant Bit Rate (CBR) transmission. Unequal error protection is based on uniform and non-uniform M-QAM constellations in conjunction with different scenarios of splitting the transmitted symbol for protection of the more important information of the video data; different constellation arrangements are proposed and evaluated to increase the capacity of the high priority layer. The performance of the transmission system is evaluated under Additive White Gaussian Noise (AWGN) and Rayleigh fading conditions. Simulation results showed that in noisy channels the decoded video can be improved by assigning a larger portion of the video data to the enhancement layer in conjunction with non-uniform constellation arrangements; in better channel conditions the quality of the received video can be improved by assigning more bits in the high priority channel and using uniform constellations. The aforementioned varying conditions can make the video transmission more successful over error-prone channels. Further techniques were developed to combat various channel impairments by considering channel coding methods suitable for layered video coding applications. It is shown that a combination of non-uniform M-QAM and forward error correction (FEC) will yield a better performance. Additionally, antenna diversity techniques are examined and introduced to the transmission system that can offer a significant improvement in the quality of service of mobile video communication systems in environments that can be modelled by a Rayleigh fading channel.