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1
Akpa, Marcellin. "Tree structure filter bank for wideband signal processing". Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/10407.
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A N-parallel branches maximally decimated filter bank is generally implemented using the polyphase components implementation. In this case, a N-th band lowpass filter is designed and its polyphase components are derived to constitute the branch 'subfilters.' This approach uses a N x N FFT matrix that will be the source of the complex (numbers) operations. Obviously, when the number of branches is equal to 2, the computations remain real. In a tree structure filter bank, the computations remain real with or without polyphase implementation. When the polyphase implementation is used, the branch signals at each stage are computed using a set of 2 x 2 FFT matrices leading to real computations. In this thesis, a new implementation approach based on the tree structured is proposed. The derivation of the structure is based on the equivalent parallel structure implementation of the tree structured filter bank. It uses the polyphase components of a given half-band lowpass filter (real coefficients) followed by a N x N Hadamard matrix. The computations, as in the original tree structured filter bank, remain real. A simplified version of the structure is a 'tree structure' followed by an N x N Hadamard matrix. A comparison between this new structure and the N parallel branch maximally decimated filter bank is made based on reconstruction error, computation complexity and processing delay.
2
Bamberger, Roberto Hugo. "The directional filter bank : a multirate filter bank for the directional decomposition of images". Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/15346.
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De, Poret Frédéric. "Filter Bank Multi-Carrier Modulation". Thesis, KTH, Kommunikationsteori, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-168383.
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During the last years, multi-carrier modulations have raised a particular interest due to their high spectral efficiency and the possible assumption of flat frequency fading. The most broadly used multi-carrier modulation is the CP-OFDM. It allows very simple equalizations methods and MIMO transcoders which keep orthogonality between carrier waveforms. However, it does not allow any waveform flexibility and is not fully spectrally efficient. Due to the low waveform flexibility its performance is quite limited in scenarios like the frequency division multiple accesses. In order to improve its performance in this case, it is important to have a multi-carrier modulation with the possibility to have a waveform well localized in time and frequency. Grey analysis shows that the only way to get both full spectral efficiency and waveforms well localized in both time and frequency domain is to give up the orthogonality in the complex field. Using filter bank multi-carrier (FBMC) with Offset-QAM (OQAM) is one combination which achieves this task. In this thesis, we study this modulation, how it is possible to efficiently modulate and demodulate it but also the transcoder (pre-coder, equalizer or both) that can be used when transmitting through multi-tap and MIMO channels. Another modulation, based on FBMC with OQAM, cyclic offset-QAM (COQAM) tries to make a tradeoff between spectral efficiency and simplicity of the equalization and transcoding methods. In this thesis, FBMC based modulation schemes are tested through different scenario: unsynchronized multi-users, unsynchronized uplink, multitaps channels, SIMO, MISO and MIMO channels. COQAM is tested with some of these scenario when it is considered as relevant to test it.Under senare år har intresset för multi-carrier modulering ökat på grund av dess höga spektrumeffektivitet under antagandet om slät frekvensfäding. Den vanligaste multicarrier moduleringen i praktiken är CP-OFDM. Denna modulering tillåter användning av enkla equalizeringsmetoder och MIMO transkodare vilket behåller ortogonalitet mellan vågformerna. Däremot tillåter den inte någon flexibilitet i val av vågform och är inte heller helt spektraleffektiv. På grund av inflexibilitet i val av vågform är dess prestanda begränsad under till exempel frekvensmultiplexing (FDMA). För att förbättra prestandan hos CP-OFDM ¨ar det viktigt att ha en modulering med möjlighet att en vågform begränsad i både tid och frekvens. Grey analys visar att det enda sättet att uppnå full spektrumeffektivitet, i kombination med vågformer som är väl begränsade i både tid och frekvens, är att ge upp ortogonaliteten i komplexa fältet. Filter Bank Multi-Carrier (FBMC) med Offset-QAM (OQAM) är ett alternativ som uppnår detta. I den här avhandlingen studeras just denna modulation, hur det är möjligt att göra effektiv modulation och demodulation, men också hur dess equalizer, pre-kodare och transkoder används vid multi-tap och MIMO-kanaler. En annan modulation, baserad på FBMC med OQAM, är cyclisk offset-QAM (COQAM). COQAM försöker göra avvägning mellan spektral effektivitet och enkelhet av utjämnings- och transkodrar metoder. I den här avhandlingen studeras både FBMC-baserade modulationer och COQAM i en rad olika scenarios: osynkroniserade multianvändare, osynkroniserad upplänk, flera vägar kanaler, SIMO, MISO och MIMO-kanaler.
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Kumar, Bhunesh. "Design of Harmonic Filters for Renewable Energy Applications". Thesis, Högskolan på Gotland, Institutionen för kultur, energi och miljö, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hgo:diva-1862.
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Harmonics are created by non-linear devices connected to the power system. Power system harmonics are multiples of the fundamental power system frequency and these harmonic frequencies can create distorted voltages and currents. Distortion of voltages and currents can affect the power system adversely causing power quality problems. Therefore, estimation of harmonics is of high importance for efficiency of the power system network. The problem of harmonic loss evaluation is of growing importance for renewable power system industry by impacting the operating costs and the useful life of the system components. Non-linear devices such as power electronics converters can inject harmonics alternating currents (AC) in the electrical power system. The number of sensitive loads that require ideal sinusoidal supply voltage for their proper operation has been increasing. To maintain the quality limits proposed by standards to protect the sensitive loads, it is necessary to include some form of filtering device to the power system. Harmonics also increases overall reactive power demanded by equivalent load. Filters have been devised to achieve an optimal control strategy for harmonic alleviation problems. To achieve an acceptable distortion, increase the power quality and to reduce the harmonics hence several three phase filter banks are used and connected in parallel. In this thesis, high order harmonics cases have been suppressed by employing variants of Butterworth, Chebyshev and Cauer filters. MATLAB/SIMULINK wind farm model was used to generate and analyze the different harmonics magnitude and frequency. High voltage direct current (HVDC) lines for an electrical grid that is more than50km far away wind farm generation plant was investigated for harmonics. These HVDC lines are also used in offshore wind farm plant. Investigated three-phase harmonics filters are shunt elements that are used in power systems for decreasing voltage distortion and for correcting the power factor. Renewable energy sources are not the stable source of energy generation like wind, solar and tidal e.t.c. Though they are secondary sources of generation and hard to connect with electrical grid. In near future the technique is to use the wave digital filter (WDF) or circulator-tree wave digital filter (CTWDF) for the renewable energy application can be employed to mitigate the harmonics. These WDF and CTWDF can b eused in HVDC lines and smart grid applications. A preliminary analysis is conducted for such a study.
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Rahimi, Siavash. "Oversampled perfect reconstruction filter bank transceivers". Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123137.
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Multicarrier modulation (MCM) is an efficient transmission technique for high data rate wired and wireless communications, where the channel bandwidth is divided into several subchannels with their own carriers. There are many different possible realizations for MCM systems, but with no doubt, orthogonal frequency division multiplexing (OFDM) has been the most prevalent solution in many current applications and standards. However, due to its use of a rectangular prototype filter, channel impairments such as narrowband interference (NBI) and carrier frequency offset (CFO) can greatly deteriorate the performance of OFDM. Moreover, future telecommunication networks call for higher data rate, increased bandwidth efficiency and flexibility in handling unsynchronized users. Filter bank multicarrier (FBMC) techniques have recently attracted considerable attention within the research community as a venue to fulfill these needs and potentially outperform the established OFDM in application areas such as dynamic spectrum access (DSA) and cognitive radio.In this context, we first propose a novel method for the design of discrete Fourier transform (DFT) modulated oversampled perfect reconstruction filter bank (OPRFB), for transmultiplexing application in MCM systems. The perfect reconstruction (PR) property is enforced by employing a parametric class of paraunitary matrices to form the transmit/receive polyphase filters of the transceiver system. Specifically, the polyphase filters are obtained by cascading special types of paraunitary matrices characterized by a limited set of design parameters. To reduce the number of these parameters, three different factorization methods are employed and compared. Through the optimization of these design parameters, the stop-band energy of the subband filters can be minimized which leads to improved spectral containment. Numerical results show that the proposed scheme leads to a clear advantage not only in additive white Gaussian noise (AWGN) and frequency selective channels, but also in the presence of channel impairments such as NBI or CFO. In particular, it is found that a significant reduction in the bit error rate (BER) can be achieved by employing the proposed scheme. Secondly, still in the context of single-user systems, we derive a data-aided joint maximum likelihood (ML) estimator of the CFO and the channel impulse response (CIR) for OPRFB transceiver systems operating over frequency selective fading channels. Then, by exploiting the structural and spectral properties of these systems, we are able to considerably reduce the complexity of the proposed estimator through simplifications of the underlying likelihood function. The Cramer Rao bound (CRB) on the variance of unbiased CFO and CIR estimators is also derived. The performance of the proposed ML estimator is investigated by means of numerical simulations under realistic conditions with CFO and frequency selective fading channels. The effects of different pilot schemes on the estimation performance for applications over time-invariant and mobile time-varying channels are also examined. The results show that the proposed joint ML estimator exhibits an excellent performance, where it can accurately estimate the unknown CFO and CIR parameters for the various experimental setups under consideration.Our third and final contribution deals with the extension of these newly proposed estimators to the multi-user case. More specifically, we consider the joint estimation of the CFO and channel equalizer coefficients based on the ML principle in the uplink of multi-user OPRFB (MU-OPRFB) systems. The performance of the proposed joint ML estimator is examined for various subband allocation schemes by means of numerical simulations. Also, different distributions of pilots over time are considered and their effects are investigated over mobile time-varying channels.La modulation à porteuses multiples (MCM) est une technique de transmission efficace pour les communications filaires et sans fil à débit de données élevé, où la bande passante est divisée en plusieurs sous-canaux ayant chacun leur propre fréquence porteuse. Il existe de multiples réalisations possibles pour les systèmes MCM, mais le multiplexage orthogonal par répartition en fréquence (OFDM) est la solution la plus répandue dans les applications et standards présentement en vigueur. Toutefois, en raison de l'utilisation de filtres de synthèse et d'analyse rectangulaires, certaines imperfections causées par le canal de transmission, tels que les interférences à bande étroite (NBI) et le décalage de la fréquence porteuse (CFO), peuvent dégrader de manière significative les performances d'OFDM. Par ailleurs, les futurs réseaux de télécommunication nécessiteront des débits de transmission plus élevés, une plus grande efficacité de la bande passante et plus de flexibilité dans la gestion d'utilisateurs multiples non synchronisés. Les techniques de bancs de filtres à porteuses multiples (FBMC) ont récemment attiré l'attention de nombreux chercheurs.Dans ce contexte, nous proposons tout d'abord une nouvelle méthode pour la conception des bancs de filtres sur-échantillonnés à reconstruction parfaite (OPRFB) basés sur la modulation par transformation de Fourier discrète (DFT), pour les applications de transmultiplexage dans les systèmes MCM. La propriété de reconstruction parfaite (PR) est assurée par l'utilisation d'une famille paramétrique de matrices para-unitaires dans la réalisation des filtres polyphasés utilisés pour la transmission et la réception des données. L'optimisation des paramètres de conception pour la méthode choisie a pour but de minimiser l'énergie des filtres de synthèse et d'analyse dans la bande de coupure, ce qui conduit à une amélioration du confinement spectral. Les résultats d'analyse et de simulations montrent que les bancs de filtres OPRFB donnent lieu à un avantage marqué. En particulier, on constate une réduction significative du taux d'erreurs binaires (BER) lors de la transmission de données au moyen de la structure OPRFB proposée.Notre deuxième contribution porte donc sur le développement et l'analyse d'un nouvel estimateur conjoint des paramètres CFO et la réponse impulsionnelle du canal (CIR) basé sur le principe de la vraisemblance maximale (ML) et utilisant une séquence d'entraînement connue, toujours dans un contexte à usager unique. La borne de Cramer Rao (CRB) sur la variance des estimateurs non-biaisés des paramètres CFO et CIR est également dérivée. La performance du nouvel estimateur ML est soumise à l'étude par l'entremise de simulations numériques dans des conditions réalistes, soit en présence de CFO et de canaux à évanouissements en fréquence sélectifs. Les effets de différents motifs de tonalités pilotes sur la performance de l'estimation sont également. Les résultats démontrent l'excellente performance du nouvel estimateur ML conjoint proposé, qui peut déterminer avec une grande précision les paramètres CFO et CIR inconnus dans les différentes configurations expérimentales soumises à l'étude.Notre troisième et dernière contribution traite de l'extension de ce nouvel estimateur ML au cas d'usagers multiple. Plus précisément, nous considérons l'estimation conjointe du CFO et des coefficients CIR basée sur le principe ML dans la liaison montante des systèmes de transmission OPRFB multi-usagers (MU-OPRFB). Suite à son extension au cas multi-usagers, la performance de l'estimateur ML conjoint est examinée à l'aide de simulations numériques pour différents schémas d'allocation des sous-bandes entre les usagers. En outre, différentes distributions de tonalités pilotes dans le temps sont prises en compte et leurs effets sont étudiés sur des canaux radio mobiles variant dans le temps. Le potentiel d'application du nouvel estimateur ML aux systèmes multi-usagers est démontré.
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Parra, Paulo Mario. "Filter-bank transforms with exact inverses". Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/289984.
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Uniformly sampled filter-bank transforms and their inverses are introduced and the conditions to obtain perfect reconstruction upon inversion are explored. It is shown that perfect reconstruction requires both filter addition and multiplication and the necessary and sufficient conditions for these operations are given. Examples indicate how to use the conditions to construct perfect-reconstruction synthesis filters from a given set of analysis filters. Additionally, an iterative scheme is presented that achieves exact inversion to an arbitrary accuracy. The methods to obtain synthesis filters are applied to discretizations of the continuous wavelet transform using both finite and infinite impulse response filters. If exact reconstruction is not a requisite, it is possible to improve imperfect-reconstruction filter banks so that their inverse is closer to the input signal. Two methods to achieve such improvement are described. To better understand the discretizations, one has to look at the continuous case. Therefore the discrete-time filter-bank transforms definitions are extended to continuous-time signal processing. It is shown that the Gabor and continuous wavelet transforms are special cases of the continuous-time extension. The methods introduced in the discrete-time case are used to derive all the linear time-invariant synthesis functions of these two transforms. A straightforward generalization of the Gabor and wavelet transforms generates filter banks whose bandwidths can vary arbitrarily with center frequency. These filters are used to create a cochlear transform, i.e., a "mixed" transform that behaves like a Gabor transform at low center frequencies and like a continuous wavelet transform at high center frequencies. The methodology described in this thesis is implemented in a set of algorithms whose complete documentation are given in chapter 4.
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Taheri, Sohail. "Performance improvement of filter bank multicarrier systems". Thesis, University of Surrey, 2018. http://epubs.surrey.ac.uk/846262/.
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Ever increasing demands for higher data rates in mobile communication present an ultimate challenge to deliver a consistent service experience to users. Filter bank multicarrier (FBMC) systems with very low out of band radiation facilitate aggregation of non-adjacent bands and asynchronous transmissions to provide the service enhancement. The primary research objective in these systems is followed by the contributions provided in this thesis. First of all, filter bank based multicarrier systems using fast convolution approach are investigated. We show that by applying FFT-based convolution without overlapped processing, the circular distortion can be discarded as a part of orthogonal interference term. The advantages of this property are spectral efficiency enhancement in the system and complexity reduction. The results show spectral efficiency enhancement by up to 15\% compared to conventional FBMC, while the complexity of the system is roughly half of conventional FBMC. Secondly, two channel estimation methods for MIMO-FBMC are proposed. The first one is a preamble-based approach aiming to reduce the preamble duration overhead and peak to average power ratio compared to the existing methods. The results confirm that this method outperforms the existing methods in terms of the mentioned parameters with up to 55\% in the overhead reduction. The second approach is a comb-based method with avoiding the contamination of pilots with symbol interference and saving time-frequency resources compared to existing methods. The results show a comparable performance of this method with is OFDM counterpart. Finally, we investigate the problems of transmitting complex symbols in FBMC systems. The challenge in these systems is designing appropriate filters to minimize the interference between adjacent subcarriers while maintaining the Nyquist property of the filter. We exploit fractional shift of the filtered symbols to compensate the deviation from the Nyquist property. The results show the proposed filter provides approximately 3 dB improvement of signal to interference ratio compared to the conventional filters.
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Larsson, Mats. "Development of a Digital Universal Filter Bank". Thesis, Uppsala universitet, Signaler och System, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-307929.
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This is a master's thesis project, which is a part of the Master Programme in Electrical Engineering at Uppsala university. When developing a product or performing measurements, it is sometimes necessary to remove some content of a signal. This might be due to an interfering source that has to be filtered out, or that only a specific frequency interval is of interest. In such a case, it would be practical if a universal frequency selective filter was available and easy to use. In this thesis, a platform for implementing different frequency selective digital filters is developed. Through a user interface, parameters such as sampling frequency, filter order, type of filter and cutoff frequencies are set by the user. This provides a platform which is easy to configure in order to run one or multiple IIR or FIR filters in various constellations. By combining different filters, a wide variety of frequency responses can be obtained. A prototype is constructed, which allows the user to connect up to two input signals and retrieve up to two output signals. The filter bank is programmed in C and implemented in a 32-bit microcontroller, base on the ARM architecture. To get a reliable prototype, a printed circuit board is designed and manufactured. To protect the electronics from external stress, a cover is designed and 3D-printed. The filter design algorithms and the algorithm used when running the filter bank gives satisfying results. The capacity of the filter bank can be increased by refining the filtering algorithm. By improving the hardware, noise generated by the electronics can be decreased. The filter bank has a really good potential to become a very useful tool.
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Demmer, David. "OFDM Precoding for Filter-Bank based Waveforms". Thesis, Paris, CNAM, 2019. http://www.theses.fr/2019CNAM1237/document.
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De nouveaux usages des systèmes de communications sans fils, tels que les réseaux de capteurs ou les voitures autonomes, ont émergé au cours des dernières années. Ces usages sont fondamentalement différents des applications haut-débit actuelles des réseaux cellulaires. La future technologie mobile, la 5G New Radio, introduit donc le concept de numérologie du signal afin de pouvoir satisfaire aux besoin hétérogènes des multiples applications supportées. En effet en supportant différentes numérologies de signaux, l'allocation temps/fréquence des signaux devient plus flexible et le signal transmis peut être adapté en conséquence. Cependant, supporte simultanément différentes numérologies génère de l'interférence et donc distord les signaux. Les filtrages spatiaux, comme la formation de faisceaux, est envisagée en 5G pour limiter l'interférence générée mais pour les communications au-dessus de 6 GHz. Il n'y a cependant pas de solutions proposées pour mes communications en-dessous de 6 GHz. Dans ce travail, des techniques d'atténuation des lobes secondaires sont étudiées pour faciliter le multiplexage des services pour les communications sous 6 GHz. L’interférence entre-utilisateurs est alors contrôlée mais la bande est également mieux utilisée. Une solution innovante, combinant bancs de filtres et orthogonalité complexe, est proposée. L'orthogonalité complexe est garanti grâce à un précodage OFDM qui remplace le précodage OQAM communément utilisé. De plus, le système développé, le Block-Filtered OFDM, utilise un récepteur 5G classique ce qui garantit la retro-compatibilité avec les techniques déjà déployée. Le modèle du BF-OFDM est entièrement décrit et adapté aux normes des réseaux mobiles. De plus, de multiples méthodes de conception des filtres prototypes sont proposées afin de mieux répondre aux besoins des systèmes. La forme d'onde étudiée est également comparée avec les autres solutions de l'état de l'art sur des scénarios d'étude classiques mais également adaptés aux nouveaux enjeux des technologies sans filsNew use cases for wireless communications recently emerged ranging from massive sensor networks to connected cars. These applications highly differ from typical signals supported by already deployed mobile technologies, which are mainly high data rate pipes. The forthcoming generation of mobile technology, 5G New Radio, introduces the concept of signal numerology so as to properly serve the requirements of the diverse applications it will support. Indeed by considering different numerologies, the time/frequency signal allocation is made more flexible which allows to shape the transmitted signal according to its needs. However, multiplexing signals with different numerologies generates interference and therefore signal distortion. Spatial filtering, such as beamforming, is envisioned for 5G above 6-GHz communications to limit inter-user interference. However, this issue still holds for sub-6 GHz systems where spatial filtering is not considered in 5G.In this work, we consider side lobe rejection techniques to ease service multiplexing in sub-6 GHz bands. Not only it provides inter-user interference mitigation but it also improves the bandwidth use efficiency in bands where frequency is a scarce resource. A novel solution, mixing filter-bank for confined spectrum and complex orthogonality for a straightforward re-use of known-how 4G/5G techniques, is proposed. The complex orthogonality is restored thanks to an OFDM precoding substituting the commonly used Offset-QAM signaling which limits the orthogonality to the real field. Moreover, the proposed solution, named Block-Filtered Orthogonal Frequency Division Multiplexing (BFOFDM), relies on a simple 5G receiver scheme which makes it backward compatible with already deployed technologies.The BF-OFDM system model is fully described and adapted to cellular standards. Besides, different prototype filter designs methods are proposed to either improve the intrinsic interference attenuation or to better confined the spectrum of the transmitted signal. Last but not least, the proposed waveform will be compared with state-of-the-art solutions for both typical and 5G oriented evaluation scenarios such as multi-service coexistence
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Ha, Hoang Kha Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Linear phase filter bank design by convex programming". Publisher:University of New South Wales. Electrical Engineering & Telecommunications, 2008. http://handle.unsw.edu.au/1959.4/43268.
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Digital filter banks have found in a wide variety of applications in data compression, digital communications, and adaptive signal processing. The common objectives of the filter bank design consist of frequency selectivity of the individual filters and perfect reconstruction of the filter banks. The design problems of filter banks are intrinsically challenging because their natural formulations are nonconvex constrained optimization problems. Therefore, there is a strong motivation to cast the design problems into convex optimization problems whose globally optimal solutions can be efficiently obtained. The main contributions of this dissertation are to exploit the convex optimization algorithms to design several classes of the filter banks. First, the two-channel orthogonal symmetric complex-valued filter banks are investigated. A key contribution is to derive the necessary and sufficient condition for the existence of complex-valued symmetric spectral factors. Moreover, this condition can be expressed as linear matrix inequalities (LMIs), and hence semi-definite programming (SDP) is applicable. Secondly, for two-channel symmetric real-valued filter banks, a more general and efficient method for designing the optimal triplet halfband filter banks with regularity is developed. By exploiting the LMI characterization of nonnegative cosine polynomials, the semi-infinite constraints can be efficiently handled. Consequently, the filter bank design is cast as an SDP problem. Furthermore, it is demonstrated that the resulting filter banks are applied to image coding with improved performance. It is not straightforward to extend the proposed design methods for two-channel filter banks to M-channel filter banks. However, it is investigated that the design problem of M-channel cosine-modulated filter banks is a nonconvex optimization problem with the low degree of nonconvexity. Therefore, the efficient semidefinite relaxation technique is proposed to design optimal prototype filters. Additionally, a cheap iterative algorithm is developed to further improve the performance of the filter banks. Finally, the application of filter banks to multicarrier systems is considered. The condition on the transmit filter bank and channel for the existence of zero-forcing filter bank equalizers is obtained. A closed-form expression of the optimal equalizer is then derived. The proposed filter bank transceivers are shown to outperform the orthogonal frequency-division multiplexing (OFDM) systems.
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Li, Yuanzhi. "Superconducting filter designs for Jodrell Bank astronomy observatory". Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.560819.
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With the increasing radio communications activities of recent years, the radio spectrum is becoming intensely crowded and this trend is set to increase at an extraordinary rate. Radio astronomy is particularly sensitive to interference of this type. A high temperature superconducting (HTS) filter, at the front-end of the receiver, has the potential to effectively eliminate the interference from adjacent bands. Such a filter will have negligible loss, have extremely sharp filter skirts and be small enough to fit into the current low temperature systems. HTS microwave filters started to emerge during the early 1990s, and since then much effort has been put into filter designs for narrow band applications. However, there are still not many wide band HTS filters reported. Here we are interested in a wide band filter for radio astronomy applications. Four HTS microstrip filters have been designed according to the specification from Jodrell Bank Radio Observatory. Among them, a nine-pole Chebyshev HTS wideband filter has been fabricated and tested. Good agreement between simulated and experimental results has been obtained. The filter has also been tested in Jodrell Bank radio astronomy. The telescope receiver system test showed that the HTS filter contributed negligible noise to one of the receiving channels when compared to the other channel without an HTS filter. The prototype filter is to be used on the Lovell Telescope in Jodrell Bank Observatory.
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Vidal, Salazar Andrea. "Wavelet packet filter bank selection for texture retrieval". Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/150619.
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Magíster en Ciencias de la Ingeniería, Mención Eléctrica.
Ingeniera Civil EléctricaDurante los últimos años, el avance de la tecnología de captura y almacenamiento ha generado un volumen sin precedentes de imágenes digitales almacenadas en las bases de datos. Esto plantea el desafío de desarrollar sistemas autónomos que sean eficientes en la búsqueda y organización del contenido digital. Como problema emblemático surgió Content-Based Image Retrieval como área de investigación. Un sistema de indexación de imágenes busca encontrar las imágenes más similares a una en particular y está compuesto de dos etapas: extracción de características y medición de similitud. La primera etapa busca la forma de representar la imagen extrayendo las características más discriminativas, mientras que la segunda etapa es usada para ordenar las imágenes de acuerdo a su similitud. Esta tesis propone el uso de Wavelet Packet para abordar el problema de indexación de imágenes de texturas. Wavelet Packet es una herramienta del procesamiento de señales que no ha sido usada en el estado del arte para enfrentar el problema de indexación y, además, es capaz del proveer distintas representaciones para una imagen. Para seleccionar la mejor representación de Wavelet Packet, este trabajo propone una nueva metodología para el problema de indexación que aborda el problema de selección de bases para la familia de Wavelet Packets utilizando el criterio de Mínima Probabilidad de Error. Como resultado de la implementación de la metodología propuesta, se muestra que las soluciones provistas por Wavelet Packet son adaptivas y mejoran el desempeño del sistema de indexación con respecto a la solución Wavelet, bajo condiciones similares y modelos estadísticos.
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Eghbali, Amir. "On Filter Bank Based MIMO Frequency Multiplexing and Demultiplexing". Thesis, Linköping University, Department of Electrical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7569.
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The next generation satellite communication networks will provide multimedia services supporting high bit rate, mobility, ATM, and TCP/IP. In these cases, the satellite technology will act as the internetwork infrastructure of future global systems and assuming a global wireless system, no distinctions will exist between terrestrial and satellite communications systems, as well as between fixed and 3G mobile networks. In order for satellites to be successful, they must handle bursty traffic from users and provide services compatible with existing ISDN infrastructure, narrowcasting/multicasting services not offered by terrestrial ISDN, TCP/IP-compatible services for data applications, and point-to-point or point-to-multipoint on-demand compressed video services. This calls for onboard processing payloads capable of frequency multiplexing and demultiplexing and interference suppression.
This thesis introduces a new class of oversampled complex modulated filter banks capable of providing frequency multiplexing and demultiplexing. Under certain system constraints, the system can handle all possible shifts of different user signals and provide variable bandwidths to users. Furthermore, the aliasing signals are attenuated by the stopband attenuation of the channel filter thus ensuring the approximation of the perfect reconstruction property as close as desired. Study of the system efficient implementation and its mathematical representation shows that the proposed system has superiority over the existing approaches for Bentpipe payloads from the flexibility, complexity, and perfect reconstruction points of view. The system is analyzed in both SISO and MIMO cases. For the MIMO case, two different scenarios for frequency multiplexing and demultiplexing are discussed.
To verify the results of the mathematical analysis, simulation results for SISO, two scenarios of MIMO, and effects of the finite word length on the system performance are illustrated. Simulation results show that the system can perform frequency multiplexing and demultiplexing and the stopband attenuation of the prototype filter controls the aliasing signals since the filter coefficients resolution plays the major role on the system performance. Hence, the system can approximate perfect reconstruction property by proper choice of resolution.
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Zhang, Haijian. "Filter Bank based MultiCarrier (FBMC) for Cognitive Radio Systems". Thesis, Paris, CNAM, 2010. http://www.theses.fr/2010CNAM0763/document.
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La radio cognitive (CR) est une radio entièrement reconfigurable qui permet de changer intelligemment ses paramètres de communication en réponse à l’activité des autres réseaux radios et demandes d’utilisateur. L’objectif ultime de la CR est de permettre à l’utilisateur secondaire (SU) d’utiliser la ressource de spectre disponible sans interférer sur l’utilisateur primaire (PU) en utilisant des trous de spectre. Par conséquent, la détection du PU est l’un des défis principaux dans le développement de la CR. Par rapport aux systèmes conventionnels de communication sans fil, le système CR introduit de nouveaux problèmes d’allocation de ressource (RA) en raison de l’interférence des canaux adjacents utilisés par le SU et le PU. Dans le contexte de la CR, la plupart des efforts ont été menés sur les systèmes de CR basés sur le multiplexage par division de fréquences orthogonales (OFDM). Toutefois, la technique de l’OFDM montre quelques points faibles dans l’application à cause des remontées significatives du spectre. Les modulations multiporteuses à base de bancs de filtre (FBMC) ont été récemment proposées pour des applications de CR. Dans cette thèse, trois points importants pour le développement d’un système de CR basé sur le FBMC sont discutés.Les trois points principaux peuvent être résumés ainsi: nous examinons premièrement les problèmes de détection de spectre des signaux OFDM et FBMC en employant le détecteur de signature de cyclostationnarité (CS). En outre, nous proposons une architecture de détection multi-bande basée sur le banc de filtre polyphasé (PFB), et montrons son avantage; deuxièmement, la comparaison entre l’OFDM et le FBMC du point de vue de l’efficacité spectrale est discutée; et enfin, nous proposons un algorithme stratégique d’allocation de ressource pour les systèmes cognitifs multi-cellulaires et multi-utilisateurs.Les algorithmes proposés dans cette thèse ont été testés par simulation. Les résultats numériques prouvent que le FBMC, par opposition à l’OFDM, pourrait réaliser une efficacité spectrale plus élevée et offre un avantage attrayant dans la détection de spectre. Les contributions de cette thèse ont accru l’intérêt d’appliquer FBMC dans les systèmes de CR à l’avenirCognitive Radio (CR) is a fully reconfigurable radio that can intelligently change its communicationvariables in response to network and user demands. The ultimate goal of CR is to allowthe Secondary User (SU) to utilize the available spectrum resource on a non-interfering basis to thePrimary User (PU) by sensing the existence of spectrum holes. Therefore, the detection of PU isone of the main challenges in the development of the CR technology. Moreover, compared to conventionalwireless communication systems, CR system poses new challenges to Resource Allocation(RA) problems because of the Cross-Channel Interference (CCI) from the adjacent channels used bySU to PU. In the CR context, most past efforts have been spent on Orthogonal Frequency DivisionMultiplexing (OFDM) based CR systems. However, OFDM technique exhibits some shortcomingsin application due to its significant spectrum leakage. Filter Bank based Multi-Carrier (FBMC), asanother promising Multi-Carrier Modulation (MCM) candidate, has been recently proposed for CRapplications. In this dissertation, three important issues in developing a FBMC based CR system arediscussed.The three prime issues can be summarized: we firstly survey the spectrum sensing problemsof OFDM and FBMC signals by using Cyclostationary Signature (CS) detector. Furthermore, wepropose a Polyphase Filter Bank (PFB) based multi-band sensing architecture, and argue for its advantage;secondly, the comparison of OFDM and FBMC from the spectral efficiency point of viewis discussed; and lastly, our emphasis is placed on the strategic resource allocation algorithms fornon-cooperative multi-cell CR systems.The overall proposed algorithms have been verified by simulation. Numerical results show thatFBMC, as opposed to OFDM, could achieve higher spectrum efficiency and attractive benefit inspectrum sensing. The contributions of this dissertation have heighten the interest in applying FBMCin the future CR systems
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Fleming, Ronald John. "Modern filter-controllers for bank-to-turn CLOS guidance". Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317063.
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Zafar, Adnan. "Filter bank based multicarrier systems for future wireless networks". Thesis, University of Surrey, 2018. http://epubs.surrey.ac.uk/846718/.
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Filter bank based multicarrier (FBMC) systems are one of the promising waveform candidates to satisfy the requirements of future wireless networks. FBMC employs prototype filters with lower side lobe and faster spectral decay, which enables it to have the advantages of reduced out-of-band energy and theoretically higher spectral efficiency (SE) compared to conventional multicarrier scheme i.e., orthogonal frequency division multiplexing (OFDM). These systems also have the ability to facilitate aggregation of non-adjacent bands to acquire higher bandwidths for data transmission. They also support asynchronous transmissions to reduce signaling overhead to meet the ever increasing demand of high data rate transmission in future wireless networks. In this work, the primary research objective is to address some of the critical challenges in FBMC systems to make it viable for practical applications. To this end, the following contributions are provided in this thesis. First of all, despite numerous advantages, FBMC systems suffers from long filter tails which may reduce the SE of the system. Filter output truncation (FOT) can reduce this overhead by discarding the filter tails but may also destroy the orthogonality in FBMC system. As a result, the signal to interference ratio (SIR) can be significantly degraded. To address this problem, we first presented a theoretical analysis on the effect of FOT in a multiple input multiple output (MIMO) FBMC system, when assuming that transmitter and receiver have the same number of antennas. We derive the matrix model of MIMO-FBMC system which is subsequently used to analyze the impact of finite filter length and FOT on the system performance. The analysis reveals that FOT can avoid the overhead in time domain but also introduces extra interference in the received symbols. To combat the interference terms, we then propose a compensation algorithm that considers odd and even overlapping factors as two separate cases, where the signals are interfered by the truncation in different ways. A general form of the compensation algorithm is then proposed to compensate all the symbols in a MIMO-FBMC block to improve the SIR values of each symbol for better detection at the receiver. Secondly, transmission of quadrature modulated symbols using FBMC systems has been an issue due to the self-interference between the transmitted symbols both in the time and frequency domain (so-called intrinsic interference). To address this issue, we propose a novel low complexity interference-free FBMC system with QAM modulation (FBMC/QAM) using filter deconvolution. The proposed method is based on inversion of the prototype filters which completely removes the intrinsic interference at the receiver and allows the use of quadrature modulated signaling. The interference terms in FBMC/QAM with and without the proposed system are analyzed and compared in terms of mean square error (MSE). It is shown with theoretical and simulation results that the proposed method cancels the intrinsic interference and improves the output signal to interference plus noise ratio (SINR) at the expense of slight enhancement of residual interferences caused by multipath channel. The complexity of the proposed system is also analyzed along with performance evaluation in an asynchronous multi-service scenario. It is shown that the proposed FBMC/QAM system with filter deconvolution outperforms the conventional OFDM system. Finally, subcarrier index modulation (SIM) a.k.a., index modulation (IM) has recently emerged as a promising concept for spectrum and energy-efficient next generation wireless communications systems due to the excellent trade-offs they offer among error performance, complexity, and SE. Although IM is well studied for OFDM, FBMC with index modulation (FBMC-IM) has not been thoroughly investigated. To address this topic, we shed light on the potential and implementation of IM technique for FBMC system. We first derived a mathematical matrix model of FBMC-IM system (FBMC/QAM-IM) along with the derivation of interference terms at the receiver due to channel distortions and the intrinsic behavior of the transceiver model. We have analytically shown that the interference power in FBMC/QAM-IM is smaller compared to that of conventional FBMC/QAM system as some subcarriers are inactive in FBMC/QAM-IM system. We then evaluated the performance of FBMC/QAM-IM in term of MSE, SIR and output SINR. The results show that combining IM with FBMC/QAM can improve the system performance since the inactive subcarriers are not contributing to the overall interference in the system. Based on the interference analysis, we then proposed an improved log-likelihood ratio (LLR) detection scheme for FBMC/QAM-IM system. At the end, BER performance of FBMC/QAM system with and without IM is presented and it can be seen that since the power from inactive subcarriers is reallocated to the active subcarriers in FBMC/QAM-IM, the system shows improved performance compared to conventional FBMC/QAM system.
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Velamala, Harika. "Filter Bank Multicarrier Modulation for Spectrally Agile Waveform Design". Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-theses/293.
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In recent years the demand for spectrum has been steadily growing. With the limited amount of spectrum available, Spectrum Pooling has gained immense popularity. As a result of various studies, it has been established that most of the licensed spectrum remains underutilized. Spectrum Pooling or spectrum sharing concentrates on making the most of these whitespaces in the licensed spectrum. These unused parts of the spectrum are usually available in chunks. A secondary user looking to utilize these chunks needs a device capable of transmitting over distributed frequencies, while not interfering with the primary user. Such a process is known as Dynamic Spectrum Access (DSA) and a device capable of it is known as Cognitive Radio. In such a scenario, multicarrier communication that transmits data across the channel in several frequency subcarriers at a lower data rate has gained prominence. Its appeal lies in the fact that it combats frequency selective fading. Two methods for implementing multicarrier modulation are non-contiguous orthogonal frequency division multiplexing (NCOFDM)and filter bank multicarrier modulation (FBMC). This thesis aims to implement a novel FBMC transmitter using software defined radio (SDR) with modulated filters based on a lowpass prototype. FBMCs employ two sets of bandpass filters called analysis and synthesis filters, one at the transmitter and the other at the receiver, in order to filter the collection of subcarriers being transmitted simultaneously in parallel frequencies. The novel aspect of this research is that a wireless transmitter based on non-contiguous FBMC is being used to design spectrally agile waveforms for dynamic spectrum access as opposed to the more popular NC-OFDM. Better spectral containment and bandwidth efficiency, combined with lack of cyclic prefix processing, makes it a viable alternative for NC-OFDM. The main aim of this thesis is to prove that FBMC can be practically implemented for wireless communications. The practicality of the method is tested by transmitting the FBMC signals real time by using the Simulink environment and USRP2 hardware modules.
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Choueiter, Ghinwa F. 1980. "A wavelet and filter bank framework for phonetic classification". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/26711.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 87-91).
by Ghinwa F. Choueiter.
S.M.
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Huynh, Nen. "A filter bank approach to automate vessel extraction with applications". Thesis, California State University, Long Beach, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1523090.
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Methods to extract vessel networks in medical images have been in high demand for its applications to health risk predictions. For example, vessel enhancement of retinal images has shown promises in diagnosing diabetes. Within the existing literature, multiscale vessel enhancement stands out as one of the best for its accuracy, speed, and simplicity. But like many vessel extraction techniques, the efficacy of the method is greatly hindered in the presence of noise, lighting variations, and decreased resolution. This deficiency is presents itself in retinal images and are particularly pronounced in digital photographs of human placenta.
Retinal images have a been popular data set of testing vessel extraction methods because of its simplicity in anatomical structure yet high hopes in diagnosing conditions such as diabetic retinopathy and glaucoma. Thus, the thesis will focus on the application of vessel extraction methods on retinal images. Specifically, we focus on the DRIVE and STARE database.
Also, recent placental pathology evidence has contributed to current understanding of causes of low birth weight and preterm birth, each has been linked to increased risk of later neurodevelopmental disorders. Among various factors that cause such disorders, the vessel network on the placenta has been hypothesized to offer the most clue in bridging that connection. Herein lies the most essential step of the blood vessel extraction, which has only been done manually through a laborious process.
Motivated by its ability to handle curvilinear structures, we propose the use of directional filter banks to further enhance the results obtained from the multiscale method. Validating experiments will be performed on a private database that is made available by the Placental Analytics, LLC.
It will be shown that for retinal images, the directional filter bank approach significantly improves the performance over the well-known multiscale vessel enhancement method. However, the directional filter bank approach are comparable to multiscale vessel enhancement on placentas.
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Cadena, Pico Jorge Eduardo. "Perfect Reconstruction Filter Bank Structure Based On Interpolated FIR Filters". Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71756.
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State of the art filter bank structures achieve practically perfect reconstruction with very high computational efficiency. However, the increase in computational requirements due to the need to process increasingly wider band signals is paramount. New filter bank structures that provide extra information about a signal while achieving the same level of required efficiency, and perfect reconstruction properties, need to be developed. In this work a new filter bank structure, the interpolated FIR (IFIR) filter bank is developed. Such a structure combines the concepts of filter banks, and interpolated FIR filters. The filter design procedures for the IFIR filter bank are developed and explained.
The resulting structure was compared with the non-maximally-decimated filter bank (NMDFB), achieving the same performance in terms of the number of multiplications required per sample and the overall distortion introduced by the system, when operating with Nyquist prototype filters.
In addition, the IFIR filter is tested in both simulated and real communication environments. Performance, in terms of bit-error-rate, was found to not be degraded significantly when using the IFIR filter bank system for transmission and reception of QPSK symbols.Master of Science
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Li, Min. "Induced norm optimal multirate filter bank design using LMI constraints /". View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202002%20LI.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.Includes bibliographical references (leaves 55-58). Also available in electronic version. Access restricted to campus users.
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Caus, López Màrius. "MIMO designs for filter bank multicarrier and multiantenna systems based on OQAM". Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/134503.
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From the perspective of increasingly data rate requirements in mobile communications, it is deemed necessary to do further research so that the future goals can be reached. To that end, the radio-based communications are resorting to multicarrier modulations and spatial diversity. Until today, the orthogonal frequency division multiplexing (OFDM) modulation is regarded as the dominant technology. On one hand, the OFDM modulation is able to accommodate multiantenna configurations in a very straightforward manner. On the other hand, the poor stopband attenuation exhibited by the OFDM modulation, highlights that a definitely tight synchronization is required. In addition, the cyclic prefix (CP) has to be sufficiently long to avoid inter-block interference, which may substantially reduce the spectral efficiency.
In order to overcome the OFDM drawbacks, the filter bank multicarrier modulation based on OQAM (FBMC/OQAM) is introduced. This modulation does not need any CP and benefits from pulse shaping techniques. This aspect becomes crucial in cognitive radio networks and communication systems where nodes are unlikely to be synchronized. In principle, the poor frequency confinement exhibited by OFDM should tip the balance towards FBMC/OQAM. However, the perfect reconstruction property of FBMC/OQAM systems does not hold in presence of multipath fading. This means that the FBMC/OQAM modulation is affected by inter-symbol and inter-carrier interference, unless the channel is equalized to some extent. This observation highlights that the FBMC/OQAM extension to MIMO architectures becomes a big challenge due to the need to cope with both modulation- and multiantenna-induced interference.
The goal of this thesis is to study how the FBMC/OQAM modulation scheme can benefit from the degrees of freedom provided by the spatial dimension. In this regard, the first attempt to put the research on track is based on designing signal processing techniques at reception. In this case the emphasis is on single-input-multiple-output (SIMO) architectures. Next, the possibility of pre-equalizing the channel at transmission is investigated. It is considered that multiple antennas are placed at the transmit side giving rise to a multiple-input-single-output (MISO) configuration. In this scenario, the research is not only focused on counteracting the channel but also on distributing the power among subcarriers. Finally, the joint transmitter and receiver design in multiple-input-multiple-output (MIMO) communication systems is covered.
From the theory developed in this thesis, it is possible to conclude that the techniques originally devised in the OFDM context can be easily adapted to FBMC/OQAM systems if the channel frequency response is flat within the subchannels. However, metrics such as the peak to average power ratio or the sensitivity to the carrier frequency offset constraint the number of subcarriers, so that the frequency selectivity may be appreciable at the subcarrier level. Then, the flat fading assumption is not satisfied and the specificities of FBMC/OQAM systems have to be considered. In this situation, the proposed techniques allow FBMC/OQAM to remain competitive with OFDM. In addition, for some multiantenna configurations and propagation conditions FBMC/OQAM turns out to be the best choice. The simulation-based results together with the theoretical analysis conducted in this thesis contribute to make progress towards the application of FBMC/OQAM to MIMO channels. The signal processing techniques that are described in this dissertation allow designers to exploit the potentials of FBMC/OQAM and MIMO to improve the link reliability as well as the spectral efficiency.
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Chen, Min. "Implementation and optimization of a modulated filter bank based on allpass filters". Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/9192.
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A filter bank based on an allpass IIR filter with brick-wall response was designed by A. J. Van Leest in [17]; however, the delay in the filter bank is too long to be used in real time applications. In order to reduce the delay, the orders of coefficients, transition bandwidth and filter bank structures must be optimized. The order of coefficients can be reduced by increasing the stopband attenuation. In order to further reduce the delay, the sharpness of the filter bank has to be reduced. This thesis also discussed the number of band and filter bank structure against to filter bank delay. The filter bank can be used in non-real time application such as CD compression with high order coefficient. The minimum transition bandwidth can be reached at 0.03257pi/number of band. This thesis expands upon DCT modulations of IIR based modulated filter banks and investigate the Hartley transformation in filter bank modulation as a new modulation technique. These modulation techniques generate the real output signal with real input signals. The quantization errors from quantizing the coefficient are studied. It is concluded that at least 16 bits are required in order for a filter bank to give a good performance as designed without quantization.
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Tzellos, Konstantinos. "Filter bank approach to the estimation of flexible modes in dynamic systems". Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Jun%5FTzellos.pdf.
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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, June 2007.Thesis Advisor(s): Roberto Cristi. "June 2007." Includes bibliographical references (p. 55-56). Also available in print.
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Nallanathan, Arumugam. "Filter bank based spreading sequences: designand performance in DS/CDMA communications systems". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B3124077X.
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Velazquez, Scott Richard. "A hybrid quadrature mirror filter bank approach to analog-to-digital conversion". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11538.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (leaf 168).
by Scott Richard Velazquez.
M.S.
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Pothuri, Aditya R. "Design of Pulse Output Direct Digital Synthesizer with an Analog Filter Bank". Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1215482245.
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Terblanche, Phillip. "Electronically adjustable bandpass filter". Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17966.
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Thesis (MScEng)--Stellenbosch University, 2011.ENGLISH ABSTRACT: This thesis presents the study, analysis and design of electronically tunable filters, that can be tuned over a wide frequency range (20-500MHz), for use in a direct sampling receiver. The final design does not have to be a single filter, but may be comprised of a filter bank which enables switching between the filters. The band of interest is too low to use normal transmission lines and lumped elements have to be used. Different topologies that can implement Coupled Resonator filters with lumped elements are investigated. Devices that can be used for tuning are also investigated and varactor diodes are found to be the most suitable tuning devices currently available. Two filters, one at the high-end and one at the low-end of the band, were designed and built, both using varactor diodes. These filters perform well in terms of tuning range, but achieving low losses with current technologies in this band remains difficult.
AFRIKAANSE OPSOMMING: Hierdie tesis meld die studie, analise en ontwerp van elektronies verstelbare filters, wat verstelbaar is oor ’n wye band (20-500MHz), vir gebruik in ’n direk-monster-ontvanger. Die finale ontwerp hoef nie ’n enkele filter te wees nie, maar kan bestaan uit ’n filterbank wat skakeling tussen die filters toelaat. Die betrokke band is te laag vir die gebruik van normale transmissielyne en diskrete komponente moet gebruik word. Verskillende topologieë wat gekoppelde resoneerder filters implementeer met diskrete komponente is ondersoek. Verstelbare komponente word ook ondersoek en varaktor diodes blyk die mees geskikte verstelbare komponent wat huidig beskikbaar is in hierdie band. Twee filters, een aan die hoë kant en een aan die lae kant van die band, is ontwerp en gebou, beide met varaktor diodes. Hierdie filters het wye verstelbare bereik, maar dit is steeds moeilik om verliese te beperk met die huidige tegnologie.
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Ju, Ziyang [Verfasser]. "A Filter Bank Based Reconfigurable Receiver Architecture for Universal Wireless Communications / Ziyang Ju". Kassel : Kassel University Press, 2010. http://d-nb.info/1016850379/34.
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Ni, Jiangqun, i 倪江群. "Study of wavelet and the filter bank theory with application to image coding". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31237599.
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Mansour, Nour [Verfasser]. "DFT Modulated Filter Bank Transceivers for Interweave and Underlay Cognitive Radio / Nour Mansour". Kassel : Kassel University Press, 2018. http://d-nb.info/1160730180/34.
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Nagy, Amr. "Performance enhancement for filter bank multicarrier methods in multi-antenna wireless communication systems". Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30532.
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This thesis investigates filter bank based multicarrier modulation using offset quadrature amplitude modulation (FBMC/OQAM), which is characterised by a critically sampled FBMC system that achieves full spectral efficiency in the sense of being free of redundancy. As a starting point, a performance comparison between FBMC/OQAM and oversampled (OS) FBMC systems is made in terms of per-subband fractionally spaced equalisation in order to compensate for the transmission distortions caused by dispersive channels. Simulation results show the reduced performance in equalising FBMC/OQAM compared to OS-FBMC,where the advantage for the latter stems from the use of guard bands. Alternatively, the inferior performance of FBMC/OQAM can be assigned to the inability of a per-subband equaliser to address the problem of potential intercarrier interference(ICI) in this system. The FBMC/OQAM system is analysed by representing the equivalent transmultiplexed channel including the filter banks as a polynomial matrix. The formulated polynomial matrix is demonstrated as a tri-diagonal matrix plus two corner elements which indicates that the induced ICI is limited to the direct adjacent spectrally overlapped subchannels. Based on polynomial matrix algebra, an equaliser is proposed which considers the cross terms between subchannels rather than performing a per-subband equalisation. The proposed equaliser is obtained through the inversion of the channel polynomial matrix; due to its reduced-rank nature, this inversion requires the extension of pseudo-inversion principles to the domain of polynomial matrices, and the inclusion of a regularisation term for enhanced stability and system performance. Some numerical examples demonstrate the ability of the proposed equaliser to suppress both ISI and ICI. Furthermore, this thesis combines FBMC/OQAM with multi-antenna architectures. In this scenario, the FBMC/OQAM system will not only suffer from ISI and ICI but also from spatial or inter-antenna interference (IAI). The multiple input multiple-output (MIMO) channel including the filter bank system is formulated as a polynomial matrix. A polynomial matrix pseudo-inverse of the equivalent channel polynomial matrix is proposed to approximately eliminate ISI, ICI, and IAI. Examples and simulation results are presented to underpin the performance of the proposed architecture.
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Nallanathan, Arumugam. "Filter bank based spreading sequences : design and performance in DS/CDMA communications systems /". Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21779120.
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Lee, Peter. "Wavelet Filter Banks in Perceptual Audio Coding". Thesis, University of Waterloo, 2003. http://hdl.handle.net/10012/927.
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This thesis studies the application of the wavelet filter bank (WFB) in perceptual audio coding by providing brief overviews of perceptual coding, psychoacoustics, wavelet theory, and existing wavelet coding algorithms. Furthermore, it describes the poor frequency localization property of the WFB and explores one filter design method, in particular, for improving channel separation between the wavelet bands. A wavelet audio coder has also been developed by the author to test the new filters. Preliminary tests indicate that the new filters provide some improvement over other wavelet filters when coding audio signals that are stationary-like and contain only a few harmonic components, and similar results for other types of audio signals that contain many spectral and temporal components.
It has been found that the WFB provides a flexible decomposition scheme through the choice of the tree structure and basis filter, but at the cost of poor localization properties. This flexibility can be a benefit in the context of audio coding but the poor localization properties represent a drawback. Determining ways to fully utilize this flexibility, while minimizing the effects of poor time-frequency localization, is an area that is still very much open for research.
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Dallmeyer, Matthew John. "Reducing Fir Filter Costs: A Review of Approaches as Applied to Massive Fir Filter Arrays". University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1417544448.
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Martinsson, Patrik. "State of Charge Estimation in a High Temperature Sodium Nickel Chloride Battery Using Kalman Filter". Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11173.
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In today’s heavy industry there are applications demanding high power supply in certain periods of a working cycle. A typical case might be startup of heavy machinery or just keeping a certain point in a distribution network at a certain energy level. To deal with this different techniques might be used, one way is to introduce a battery as an energy reserve in the system. One battery studied at ABB for this purpose is the so called High Temperature Sodium Nickel Chloride battery and a model of this battery has been developed at ABB. When operating a battery of the mentioned type in an application it is important to keep track of the energy stored in the battery. Earlier tests has shown that this is difficult in a noisy environment.
This master thesis investigates if a Kalman filter may be used to estimate the energy stored in the battery. The investigation is performed in steps, starting with a simplified model of the battery and then expanding to a more complete model. Evaluation of the methods and algorithms used is made by simulations and based on the assumption that there is a good model available. The model is special in such a way that it has a varying number of states despite that the number of outputs remains the same.
Some comparisons with actual measurements are also made and an analysis of the parameters in the model along with an introduction to the system identification problem is discussed, assuming that the structure of the model is correct.
I dagens tunga industri finns applikationer som kräver höga effektuttag under vissa perioder av en arbetscykel. Ett typiskt fall kan vara uppstart av tunga maskiner eller att hålla en given spänningsnivå i en belastningspunkt i ett distributionsnät. För att hantera detta finns olika metoder, en möjlighet är att använda ett batteri som en energireserv. Ett högtemperaturbatteri har studerats på ABB för detta ändamål och en model av detta batteri har tagits fram. När ett sådant batteri används är det viktigt att kontinuerligt veta hur mycket energi som finns till förfogande i batteriet. Tidigare tester har visat att detta är svårt i en brusig miljö.
I detta examensarbete kommer det undersökas om ett Kalman filter kan användas för att skatta energin i detta batteri. Undersökningen sker i steg och startar med en förenklad modell som sedan utvecklas till en mer komplett modell. Utvärdering av de metoder och algoritmer som används sker via simuleringar och baseras på antagandet att modellen är komplett och riktig. Denna modell är speciell på det sätt att den har ett variabelt antal tillstånd trots att antalet utsignaler är konstant.
Viss jämförelse med de mätningar som finns tillgängliga görs och en inledande analys av de ingående modellparametrarna presenteras. Även en introduktion till det omfattande systemidentifieringsproblemet diskuteras, med antagandet att modellens struktur är korrekt.
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Nayebi, Kambiz. "A time domain framework for the analysis and design of FIR multirate filter bank systems". Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/13867.
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Zakaria, Rostom. "Transmitter and receiver design for inherent interference cancellation in MIMO filter-bank based multicarrier systems". Phd thesis, Conservatoire national des arts et metiers - CNAM, 2012. http://tel.archives-ouvertes.fr/tel-00923184.
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Multicarrier (MC) Modulation attracts a lot of attention for high speed wireless transmissions because of its capability to cope with frequency selective fading channels turning the wideband transmission link into several narrowband subchannels whose equalization, in some situations, can be performed independently and in a simple manner. Nowadays, orthogonal frequency division multiplexing (OFDM) with the cyclic prefix (CP) insertion is the most widespread modulation among all MC modulations, and this thanks to its simplicity and its robustness against multipath fading using the cyclic prefix. Systems or standards such as ADSL or IEEE802.11a have already implemented the CP-OFDM modulation. Other standards like IEEE802.11n combine CP-OFDM and multiple-input multiple-output (MIMO) in order to increase the bit rate and to provide a better use of the channel spatial diversity. Nevertheless, CP-OFDM technique causes a loss of spectral efficiency due to the CP as it contains redundant information. Moreover, the rectangular prototype filter used in CP-OFDM has a poor frequency localization. This poor frequency localization makes it difficult for CP-OFDM systems to respect stringent specifications of spectrum masks.To overcome these drawbacks, filter-bank multicarrier (FBMC) was proposed as an alternative approach to CP-OFDM. Indeed, FBMC does not need any CP, and it furthermore offers the possibility to use different time-frequency well-localized prototype filters which allow much better control of the out-of-band emission. In the literature we find several FBMC systems based on different structures. In this thesis, we focus on the Saltzberg's scheme called OFDM/OQAM (or FBMC/OQAM). The orthogonality constraint for FBMC/OQAM is relaxed being limited only to the real field while for OFDM it has to be satisfied in the complex field. Consequently, one of the characteristics of FBMC/OQAM is that the demodulated transmitted symbols are accompanied by interference terms caused by the neighboring transmitted data in time-frequency domain. The presence of this interference is an issue for some MIMO schemes and until today their combination with FBMC remains an open problem.The aim of this thesis is to study the combination between FBMC and MIMO techniques, namely spatial multiplexing with ML detection. In the first part, we propose to analyze different intersymbol interference (ISI) cancellation techniques that we adapt to the FBMC/OQAM with MIMO context. We show that, in some cases, we can cope with the presence of the inherent FBMC interference and overcome the difficulties of performing ML detection in spatial multiplexing with FBMC/OQAM. After that, we propose a modification in the conventional FBMC/OQAM modulation by transmitting complex QAM symbols instead of OQAM ones. This proposal allows to reduce considerably the inherent interference but at the expense of the orthogonality condition. Indeed, in the proposed FBMC/QAM,the data symbol and the inherent interference term are both complex. Finally, we introduce a novel FBMC scheme and a transmission strategy in order to avoid the inherent interference terms. This proposed scheme (that we call FFT-FBMC) transforms the FBMC system into an equivalent system formulated as OFDM regardless of some residual interference. Thus, any OFDM transmission technique can be performed straightforwardly to the proposed FBMC scheme with a corresponding complexity growth. We develop the FFT-FBMC in the case of single-input single-output (SISO) configuration. Then, we extend its application to SM-MIMO configuration with ML detection and Alamouti coding scheme.
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Weaver, Michael B. "Performance comparison between three different bit allocation algorithms inside a critically decimated cascading filter bank". Diss., Online access via UMI:, 2009.
Znajdź pełny tekst źródłaStreszczenie:
Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Electrical and Computer Engineering, 2009.Includes bibliographical references.
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Wieben, Oliver. "The classification of PVCs using filter bank features, induction of decision trees and a fuzzy-rule-based system". 1996. http://catalog.hathitrust.org/api/volumes/oclc/37162236.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1996.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 24-26).
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Chen, Shih-Heng, i 陳仕衡. "FDM Using Modulation Filter Bank". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/65642472096065833494.
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碩士國立交通大學
電信研究所
85
Digital implementation of frequency division multiplexing is investigated withthe use of perfect reconstruction filter bank. The PR filter bank is shown tobe equivalent to a cross talk free trans-multiplexer with synthesis section as the multiplexing input and the analysis section as the de-multiplexing output. With such filter bank implementation, both the QAM multiplexing and the VSB multiplexing are simulated. The advantage of such digital implementation is that the bandwidth utilization can be maximized and the band assignment can beeasily achieved as the selection of the modulation interpolation filter.
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"Adaptive Filter Bank Time-Frequency Representations". Master's thesis, 2012. http://hdl.handle.net/2286/R.I.15948.
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abstract: A signal with time-varying frequency content can often be expressed more clearly using a time-frequency representation (TFR), which maps the signal into a two-dimensional function of time and frequency, similar to musical notation. The thesis reviews one of the most commonly used TFRs, the Wigner distribution (WD), and discusses its application in Fourier optics: it is shown that the WD is analogous to the spectral dispersion that results from a diffraction grating, and time and frequency are similarly analogous to a one dimensional spatial coordinate and wavenumber. The grating is compared with a simple polychromator, which is a bank of optical filters. Another well-known TFR is the short time Fourier transform (STFT). Its discrete version can be shown to be equivalent to a filter bank, an array of bandpass filters that enable localized processing of the analysis signals in different sub-bands. This work proposes a signal-adaptive method of generating TFRs. In order to minimize distortion in analyzing a signal, the method modifies the filter bank to consist of non-overlapping rectangular bandpass filters generated using the Butterworth filter design process. The information contained in the resulting TFR can be used to reconstruct the signal, and perfect reconstruction techniques involving quadrature mirror filter banks are compared with a simple Fourier synthesis sum. The optimal filter parameters of the rectangular filters are selected adaptively by minimizing the mean-squared error (MSE) from a pseudo-reconstructed version of the analysis signal. The reconstruction MSE is proposed as an error metric for characterizing TFRs; a practical measure of the error requires normalization and cross correlation with the analysis signal. Simulations were performed to demonstrate the the effectiveness of the new adaptive TFR and its relation to swept-tuned spectrum analyzers.Dissertation/Thesis
M.S. Electrical Engineering 2012
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Chang, Che-Shuo, i 張哲碩. "Filter-based Empirical Mode Decomposition and Its Application to Filter Bank Design". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/63714394844134373130.
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碩士國立臺灣大學
電信工程學研究所
100
The empirical mode decomposition (EMD) has been widely applied to many research fields for decomposing the signal. The algorithm is based on the spline interpolation of local extreme points. This procedure makes it difficult to analyze the performance and the corresponding mathematical properties. Thus till now most of knowledges about EMD are based on practical observations. In addition, the EMD itself has little flexibility to adapt to different requirement. In this work, the proposed filter-based empirical mode decomposition (FB-EMD) provides a parametrized algorithm adjustable for different settings. In this way it is possible to change the decreasing rate of the cutoff frequency of the intrinsic mode function (IMF). Moreover, the equivalent filter bank and the decomposition results are predictable and controllable. This enables us to apply the FB-EMD to the filter bank design. Another feature of the FB-EMD is that the algorithm is resistant to the noise and intermittencies. While being free from the boundary process and the mode mixing problem, the proposed method is also efficient. The numerical results show that in general the FB-EMD have better performance in real signals and autoregressive moving-average signals. The spectral overlap is also reduced. These discussions and the numerical results is helpful for developing a theoretic framework for the EMD based algorithm.
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Chiang, Hwang-Cheng, i 姜皇成. "Implementation and Application of Sinusoidal Modulated Filter Bank". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/56086491167320310213.
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博士大同工學院
電機工程學系
84
Multirate signal processing has been a growing field for more than one decade. The analysis-synthesis systems have found many applicationssuch as speech, image coding, transmultiplexing, adaptive filteringand spectral analysis. One of the issues recognized as being importantto the successful application of these systems is the computational complexity. A significant solution to reducing the computational complexity is based on the sinusoidal modulated filter banks. Traditionalblock transforms, including the DFT, DHT, DCT, and DST, and the extendedlapped transform are all examples of the sinusoidal modulated filterbanks. In this dissertation, we pay our attention to implenentationand application of the sinusoidal modulated filter banks. We propose two implementations for the modulated filter banks: 1. We present a unified second order structure for computation of filter banks with arbitrary length of basis functions. For the regularity and parallelism of the structure, the new scheme really provides a low cost hardware implementation and is especially suitable for VLSI technologies. 2. For the M-band cosine modulated filter banks, the analysis and synthesis sections are efficiently implemented with two M-point of DFTs and some extra operations. In addition, two main applications of the DFT and DCT filterbanks are discussed in detail: 1. The DFT filter bank is used for fast FIR filtering in the transform domain. From a measure of computational complexity, the proposed implementation has been proved to have better performance than the overlap-add and overlap- save algorithms. 2. The analysis filters of the DCT filter bank are converted into a unified second filter form which requires only two multipliers and five adders to implement. The structure is used as a prefilter for efficient digital filter design. The proposed prefilter structure has been proved to be an efficient one for the design of lowpass, bandpass and highpass digital filters simutaneously.
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Hsu, Shih-huai, i 許時懷. "Improved Filter-bank of Speech Feature Coefficient Extraction". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/46443189430807779003.
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碩士國立中央大學
電機工程學系
103
The theme of this thesis is to improve the part of feature extraction in the speech keyword recognition. In the framework of the entire keyword recognition system, feature extraction is to highlight the individual features of different voices, and can reduce the amount of data by means of the extract process. Many researchers have presented different ways to extract the speech features in the literature, or on which making improvements at extracting feature coefficient method. This thesis discusses several improved filter bank in mel-frequency cepstral coefficients (MFCC). The best filter bank is used to replace the original mel-triangular filter set. The experimental results showed that the application of this improved filter bank can effectively improve the recognition rate of the keyword extraction system.
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Yeh, Ming-Chen, i 葉銘琛. "Subband Image Coding using Hierachical Hexagonal Filter Bank". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/81733718594267634781.
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ElGarewi, Ahmed. "Analysis of algorithms for filter bank design optimization". Thesis, 2019. http://hdl.handle.net/1828/11131.
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This thesis deals with design algorithms for filter banks based on optimization. The design specifications consist of the perfect reconstruction and frequency response specifications for finite impulse response (FIR) analysis and synthesis filters. The perfect reconstruction conditions are formulated as a set of linear equations with respect to the analysis filters’ coefficients and the synthesis filters’ coefficients. Five design algorithms are presented. The first three are based on an unconstrained optimization of performance indices, which include the perfect reconstruction error and the error in the frequency specifications. The last two algorithms are formulated as constrained optimization problems with the perfect reconstruction error as the performance index and the frequency specifications as constraints. The performance of the five algorithms is evaluated and compared using six examples; these examples include uniform filter bank, compatible non-uniform filter bank and incompatible non-uniform filter bank designs. The evaluation criteria are based on distortion and aliasing errors, the magnitude response characteristics of analysis and synthesis filters, the computation time required for the optimization, and the convergence of the performance index with respect to the number of iterations. The results show that the five algorithms can achieve almost perfect reconstruction and can meet the frequency response specifications at an acceptable level. In the case of incompatible non-uniform filter banks, the algorithms have challenges to achieve almost perfect reconstruction.Graduate
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Lee, Yu-An, i 李祐安. "Implementation of Filter Bank Multicarrier System using SDR". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/6k6s2q.
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碩士國立中山大學
通訊工程研究所
107
Current wireless communication systems mainly adopt the multicarrier transmission in the physical layers due to the higher spectrum utilization in frequency selective fading channel. The prominent design is the orthogonal frequency division multiplexing (OFDM) system, where the signals are transmitted by the individually orthogonal carriers with rectangular shaping waveforms. However, the rectangular waveforms essentially spread its frequency response, interfering the adjacent sub-band systems. In this regard, the filter bank multi-carrier/offset quadrature amplitude modulation (FBMC/OQAM) was developed to reduce the sidelobes of a subcarrier by using a smoother shaping waveforms. Accordingly, it becomes a promising technology for the next generation wireless systems. In this thesis, we develop the transceiver design with FBMC/OQAM modulation system in a Xilinx software-defined radio (SDR) platform, where the both synchronization, channel estimation and detection are implemented. Finally, we successively transmit a photo in our developed benchmark.
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Li, Chia-Lun, i 李嘉倫. "Research on Four-Channel Switchable Bandpass Filter Bank". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/48etpg.
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碩士國立中央大學
電機工程學系
107
This thesis uses SP4T to switch the four different passband paths. The center frequencies of four passband are 1.25 GHz, 1.75 GHz, 2.25 GHz, and 2.75 GHz. Both of them are 500 MHz bandwidth, and the other hand the lower center frequency, the higher passband bandwidth be. By comparing different circuits, chooses the better circuit design to match the passbands of different center frequencies and bandwidths. With the metal housing to shield the noise from the outside can improve the response of the stopband. And the circuit used two SP4T to complete the design of the four-channel switchable bandpass filter. By comparing the different circuit design, use the design with the best selectivity and smaller area. The three-mode resonator is used to design the band 1. And the others use the hairpin bandpass filter, because the thicker PCB has stronger coupling in the same gap to improve the success rate of the etching process. And even can use the Chebyshev prototype parameters to design the bands systematically. However, the passband of the 2.25 GHz center frequency used stepped impedance resonator (Stepped Impedance Resonator) to make the first harmonic frequency higher. And there are two different welding process for the QFN and QSOP package to improve the success rate of welding and even low cost. The circuit size finally is 13 cm × 8.5 cm. The lowest insertion loss of each passband is 5.5 dB, 8.58 dB, 7.84 dB and 7.91 dB. The S21 of the stop band is all below -20 dB, and each passband is switchable.
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Guo, Shu-Na, i 郭淑娜. "Equalizer Design and Implementation for Filter Bank Multicarrier System". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/97220431748673021277.
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碩士國立中央大學
電機工程學系
105
Orthogonal frequency division multiplexing (OFDM) utilizes the quadrature characteristics of the subcarriers and the cyclic prefix to eliminate inter-symbol and inter-carrier interference. Filter bank Multicarrier (FBMC) uses offset quadrature amplitude modulation (OQAM) to maintain the orthogonality between adjacent subcarriers and a filter with good stopband attenuation to avoid the circular convolution aliasing. So the FBMC didn’t need the cyclic prefixes can also eliminate symbols between the interference, leading to higher bandwidth efficiency. In this paper, we analyze how to eliminate the inter-symbol interference and inter-carrier interference in the receiver of the FBMC. Channel estimation is performed using the preamble under the WIMAX specification, and the channel effect is compensated using a single carrier frequency domain equalizer. Equalizer has three options: 1. Finite impulse response equalizer. 2. Minimum mean square frequency domain equalizer. 3. Decision feedback equalizer. We would compare those equalizers based on simulation results. The decision feedback equalizer employed since it is able to achieve the 10-2 bit error rate threshold at SNR that is lower than other equalizers. Decision feedback equalizer is descripted with Verilog HDL, and used FPGA to verify its circuit design.