Dissertations / Theses: 'Filter banks'

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Demirsoy, SuÌˆleyman SÄ±rrÄ±. "Complexity reduction in digital filters and filter banks." Thesis, University of Westminster, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433680.

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Nord, Magnus. "Cosine Modulated Filter Banks." Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1641.

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The initial goal of this report was to implement and compare cosine modulated filter banks. Because of time limitations, focus shifted towards the implementation. Filter banks and multirate systems are important in a vast range of signal processing systems. When implementing a design, there are several considerations to be taken into account. Some examples are word length, number systems and type of components. The filter banks were implemented using a custom made software, especially designed to generate configurable gate level code. The generated code was then synthesized and the results were compared. Some of the results were a bit curious. For example, considerable effort was put into implementing graph multipliers, as these were expected to be smaller and faster than their CSDC (Canonic Signed Digit Code) counterparts. However, with one exception, they turned out to generate larger designs. Another conclusion drawn is that the choice of FPGA is important. There are several things left to investigate, though. For example, a more thorough comparison between CSDC and graph multipliers should be carried out, and other DCT (Discrete Cosine Transform) implementations should be investigated.

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Rosenbaum, Linnea. "On low-complexity frequency selective digital filters and filter banks." Doctoral thesis, Linköpings universitet, Elektroniksystem, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8930.

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En filterbank består av flera filter som arbetar tillsammans för att dela upp en signal i olika frekvensband. De kan också användas för att slå ihop signaler separerade i frekvensplanet till en enda. Sedan tidigt 70-tal har man lärt sig att designa förlustfria filterbankar som alltså inte introducerar några som helst fel i systemet. Sådana filterbankar kallas PR-filterbankar, där PR står för 'perfekt rekonstruktion'. Exempel på applikationer där filterbankar används är bildkodning, audiokodning, kommunikationssystem och omvandling av analoga signaler till digitala (A/D-omvandling). Under de senaste åren har det framkommit att genom att lätta på kraven gällande perfekt rekonstruktion, går det att markant minska den erforderliga aritmetiska komplexiteten. Eftersom de flesta system i sig inte är förlustfria, kan man utan att egentligen påverka den totala prestandan tillåta små fel i filterbanken, så l¨ange dessa fel är försumbara i jämförelse med andra felkällor som t.ex. kvantisering och avrundning. Avhandlingen behandlar digitala filter och likformiga icke-PR-filterbankar. Merparten av filterbankarna är realiserade med någon slags moduleringsteknik (cosinus-, sinus- eller komplexmodulering). Den röda tråden genom avhandlingen är kombinationen av tämligen smala övergångsband och samtidigt låg aritmetisk komplexitet. Ett sätt att uppnå denna kombination är att använda sig av en teknik som heter frekvenssvarsmaskning och förkortas FRM. Denna metod har på ett framgångsrikt sätt använts i avhandlingen. En potentiell nackdel med FRMmetoden är att den medför en längre fördröjning genom systemet. Därför föreslås också ett sätt att syntetisera FRM-filter med låg fördröjning. Här optimeras filtren både med avseende på komplexitet och fördröjning samtidigt. En annan metod som utnyttjats för att kombinera relativt smala övergångsband med låg aritmetisk komplexitet är att använda IIR filter istället för FIR filter. Ett flertal exempel på filter och filterbankar, optimerade och syntetiserade i Matlab, illustrerar fördelarna med de föreslagna filter- och filterbanks-klasserna.
Filter banks are systems of several filters with a common input or a common output. They are used whenever a signal needs to be split into different frequency bands. Since the early seventies, the theory of digital filter banks has developed to a mature state. Today there exist numerous ways to design filter banks for different applications, such as image and audio coding, transmultiplexing in communication systems, echo cancellation, and analog-to-digital (A/D) conversion systems. However, earlier work has to a large extent been on the transfer function level, whereas in this thesis work, efficient realizations, important in e.g. low-power applications, are in focus. Further, most of the previous work have been focused on the perfect reconstruction (PR) case, which is, for many applications an unnecessarily severe restriction. It has been show that by relaxing the requirements on perfect reconstruction, and allowing the filter banks to have some errors, the arithmetic complexity can be reduced significantly. This thesis treats digital filters and uniform non-PR filter banks. A major part of the filter banks are realized using different modulation schemes (complex, cosine, or sine modulation). The governing idea through the thesis is the combination of frequency selectivity and low arithmetic complexity. One example on how to achieve frequency selective digital filters and filter banks with low arithmetic complexity is to use the frequency-response masking (FRM) approach. This approach together with the idea of using IIR filters instead of FIR filters is successfully used in the thesis. The price to pay for the reduced arithmetic complexity using FRM filters is unfortunately a longer overall delay. Therefore, some work has ben done in the field of low-delay FRM FIR filters as well. These filters are optimized on both low delay and low arithmetic complexity simultaneously. A number of design examples are included in order to demonstrate the benefits of the new classes of filters and filter banks.

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Rosenbaum, Linnéa. "On low-complexity frequency selective digital filters and filter banks /." Linköping : Department of Eelectrical Engineering, Linköpings universitet, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8930.

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Anderson, Martin S. "Design of two-dimensional PCAS digital filters and filter banks." Thesis, University of Warwick, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307968.

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Chen, Tsuhan Vaidyanathan P. P. Vaidyanathan P. P. "Multidimensional multirate filters and filter banks : theory, design, and implementation /." Diss., Pasadena, Calif. : California Institute of Technology, 1993. http://resolver.caltech.edu/CaltechETD:etd-08232007-095226.

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Law, Ying Man. "Iterative algorithms for the constrained design of filters and filter banks /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20LAW.

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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004.
Includes bibliographical references (leaves 108-111). Also available in electronic version. Access restricted to campus users.

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Ramachandran, Ravi P. "Bandwidth efficient filter banks for transmultiplexers." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74561.

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This thesis addresses the problem of simultaneously transmitting several data signals across a single channel. For this purpose, a transmultiplexer that uses modulated filter banks is studied. Modulated filter banks comprise filters that are bandpass versions of a lowpass prototype. The filters serve to assign portions of the channel bandwidth to the data signals. The impulse responses of the filters are parameterized by a center frequency, delay and phase factor. The objectives in configuring modulated filter banks are to use the full channel bandwidth for transmission, cancel crosstalk between signals (arises when signals share bandwidth) and cancel intersymbol interference in each data signal. Assuming an ideal channel, a synthesis procedure is developed by assigning a bandwidth to the lowpass prototype and deriving relationships among the center frequencies, delays and phases such that the entire channel bandwidth is utilized and crosstalk is cancelled. New design procedures for an FIR lowpass prototype are proposed such that the intersymbol interference is suppressed. One design method is based on a minimax criterion. Another approach involves an unconstrained optimization of an error function.
The synthesis procedure leads to five bandwidth efficient transmultiplexers. Three of the systems implement multicarrier Quadrature Amplitude Modulation (QAM) and two accomplish multicarrier Vestigial Sideband Modulation (VSB). The performance of the five systems is compared with filters obtained by the new design approaches. Also, the issue of channel distortion is addressed. Finally, the transmultiplexers can be converted into new subband systems.

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Dachasilaruk, Siriporn. "Wavelet filter banks for cochlear implants." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/388109/.

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Cochlear implant (CI) users regularly perform as well as normal-hearing (NH) listeners in quiet conditions. However, CI users have reduced speech perception in noise. CI users suffer more in terms of speech intelligibility than NH listeners in the same noisy environment. Speech coding strategies with noise reduction algorithms for CI devices play an important role, allowing CI users to benefit more from their implants. This thesis investigates a wavelet packet-based speech coding strategy with envelope-based noise reduction algorithms to enhance speech intelligibility in noisy conditions. The advantages of wavelet packet transforms (WPTs), in terms of time-frequency analysis, the sparseness property, and low computational complexity, might make WPT appropriate for speech coding and denoising in CI devices. In cases with an optimal set of parameters for a wavelet packet-based speech coding strategy, the 23- and 64-band WPTs with sym8 and frame length of 8 ms were found to be more suitable than other combinations for this strategy. These parameters can optimise speech intelligibility to benefit CI users. However, both the standard ACE strategy and the wavelet packet-based strategy provided almost the same results in either quiet or noisy conditions. Cases using envelope-based denoising techniques in a wavelet packet-based strategy, namely time-adaptive wavelet thresholding (TAWT) and time-frequency spectral subtraction (TFSS) were developed and evaluated by objective and subjective intelligibility measures and compared to ideal binary masking (IdBM) as a baseline for denoising performance. IdBM can restore intelligibility to nearly the same level as NH listeners in all noisy conditions. Both TAWT and TFSS showed slight intelligibility improvements in some noisy conditions. This may result from noise estimation in denoising techniques. Noise level may be under- or overestimated, and this results in distortion in enhanced speech and difficult in speech discrimination. Both objective and subjective intelligibility measures can predict the trend of the performance of different denoising techniques for CI users. However, NH listeners can achieve better intelligibility at higher SNR levels without noise reduction, since they are less sensitive to noise but more sensitive to speech distortion when compared to CI listeners. Therefore, denoising techniques may work well for CI users in further investigations.

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Lettsome, Clyde Alphonso. "Fixed-analysis adaptive-synthesis filter banks." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28143.

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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Smith, Mark J. T.; Committee Co-Chair: Mersereau, Russell M.; Committee Member: Anderson, David; Committee Member: Lanterman, Aaron; Committee Member: Rosen, Gail; Committee Member: Wardi, Yorai.

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Waldhauser, Dirk S. "Multicarrier systems based on filter banks." Aachen Shaker, 2009. http://d-nb.info/997085916/04.

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Baicher, Gurvinder Singh. "Towards optimisation of digital filters and multirate filter banks through genetic algorithms." Thesis, University of South Wales, 2003. https://pure.southwales.ac.uk/en/studentthesis/towards-optimisation-of-digital-filters-and-multirate-filter-banks-through-genetic-algorithms(1ed2778b-e27b-4434-bc50-915f697a0d6b).html.

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This thesis is concerned with the issues of design and optimisation of digital filters and multirate filter banks. The main focus and contribution of this thesis is to apply the genetic algorithm (GA) technique and to draw some comparison with the standard gradient and non-gradient based optimisation methods. The finite word length (FWL) constraint affects the accuracy of a real-time digital filter requency response. For the case of digital filters, this study is concerned with the optimisation of FWL coefficients using genetic algorithms. Some comparative study with the simple hill climber algorithms is also included. The outcome of this part of the study demonstrates a substantial improvement of the new results when compared with the simply rounded FWL coefficient frequency response. The FWL coefficient optimisation process developed in the earlier Chapters is extended to the field of multirate filter banks. All multirate filter banks suffer from the problems of amplitude, phase and aliasing errors and, therefore, constraints for perfect reconstruction (PR) of the input signal can be extensive. The problem, in general, is reduced to relaxing constraints at the expense of errors and finding methods for minimising the errors. Optimisation techniques are thus commonly used for the design and implementation of multirate filter banks. In this part of the study, GAs have been used in two distinct stages. Firstly, for the design optimisation so that the overall errors are minimised and secondly for FWL coefficient optimisation of digital filters that form the sub-band filters of the filter bank. This process leads to an optimal realisation of the filter bank that can be applied to specific applications such as telephony speech signal coding and compression. One example of the optimised QMF bank was tested on a real-time DSP target system and the results are reported. The multiple M-channel uniform and non-uniform filter banks have also been considered in this study for design optimisation. For a comparative study of the GA optimised results of the design stage of the filter bank, other standard methods such as the gradient based quasi-Newton and the non-gradient based downhill Simplex methods were also used. In general, the outcome of this part of study demonstrates that a hybrid approach of GA and standard method was the most efficient and effective process in generating the best results.

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Steffen, Andreas. "Digital pulse compression using multirate filter banks /." [S.l.] : [s.n.], 1991. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=9471.

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Hjørungnes, Are. "Optimal Bit and Power Constrained Filter Banks." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, 2000. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-450.

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In this dissertation, two filter banks optimization problems are studied. The first problem is the optimization of filter banks used in a subband coder under a bit constraint. In the second problem, a multiple input multiple output communication system is optimized under a power constraint. Three different cases on the filter lengths are considered: unconstrained length filter banks, transforms, and finite impulse response filter banks with arbitrary given filter lengths.

In source coding and multiple input multiple output communication systems, transforms and filter banks are used to decompose the source in order to generate samples that are partly decorrelated. Then, they are more suitable for source coding or transmission over a channel than the original source samples. Most transformers and filter banks that are studies in the literature have the perfect reconstruction property. In this dissertation, the perfect reconstruction condition is relaxed, so that the transforms and filter banks are allowed to belong to larger sets, which contain perfect reconstruction transforms and filter banks as subsets.

Jointly optimal analysis and synthesis filter banks and transforms are proposed under the bit and power constraints for all the three filter length cases. For a given number of bits used in the quantizers or for a given channel with a maximum allowable input power, the analysis and synthesis transforms and filter banks are jointly optimized such that the mean square error between the original and decoded signal is minimized. Analytical expressions are obtained for unconstrained length filter banks and transforms, and an iterative numerical algorithm is proposed in the finite impulse response filter bank case.

The channel in the communication problem is modelled as a known multiple input multiple output transfer matrix with signal independent additive vector noise having known second order statistics. A pre- and postprocessor containing modulation is introduced in the unconstrained length filter bank system with a power constraint. It is shown that the performance of this system is the same as the performance of the power constrained transform coder system when the dimensions of the latter system approach infinity.

In the source coding problem, the results are obtained with different quantization models. In the simplest model, the subband quantizers are modelled as additive white signal independent noise sources. The proposed unconstrained length filter banks, and it is shown that the proposed transform has better performance than the Karhunen-Loève transform. Also, the proposed transform coder has the same performance as a transform coder using a reduced rank Karhunen- Loève analysis transform with jointy optimal bit allocation and Wiener synthesis transform. The proposed finite impulse response filter banks have at least as good theoretical rate distortion performance as the perfect reconstruction filter banks and the finite impulse response Wiener filter banks used in the comparison.

A practical coding system is introduced where the coding of the subband signals is performed by uniform threshold quantizers using the centroids as representation levels. It is shown that there is a mismatch between the theoretical and practical results. Three methods for removing this mismatch are introduced. In the two first methods, the filter banks them selves are unchanged, but the coding method of the subband signals is changed. In the first of these two methods, quantizers are derived such that the additive coding noise and subband signals are uncorrelated. Subtractive dithering is the second method used for coding of the subband signals. In the third method, a signal dependent colored noise model is introduced, and this model is used to redesign the filter banks. In all three methods, good correspondence is achieved between the theoretical and practical results, and comparable or better practical rate distortion performance is achieved by the proposed methods compared to systems using perfect reconstruction filter banks and finite impulse response Wiener synthesis filter banks.

Finally, conditions for when finite impulse response filter banks are optimal are derived.

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Eghbali, Amir. "Contributions to Reconfigurable Filter Banks and Transmultiplexers." Doctoral thesis, Linköpings universitet, Elektroniksystem, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-60929.

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A current focus among communication engineers is to design flexible radio systems to handle services among different telecommunication standards. Thus, lowcost multimode terminals will be crucial building blocks for future generations of multimode communications. Here, different bandwidths, from different telecommunication standards, must be supported. This can be done using multimode transmultiplexers (TMUXs) which allow different users to share a common channel in a time-varying manner. These TMUXs allow bandwidth-on-demand. Each user occupies a specific portion of the channel whose location and width may vary with time. Another focus among communication engineers is to provide various wideband services accessible to everybody everywhere. Here, satellites with high-gain spot beam antennas, on-board signal processing, and switching will be a major complementary part of future digital communication systems. Satellites provide a global coverage and customers only need to install a satellite terminal and subscribe to the service. Efficient utilization of the available limited frequency spectrum, calls for on-board signal processing to perform flexible frequency-band reallocation (FFBR). This thesis outlines the design and realization of reconfigurable TMUX and FFBR structures which allow dynamic communication scenarios with simple software reconfigurations. In both structures, the system parameters are determined in advance. For these parameters, the required filter design problems are solved only once. Dynamic communications, with users having different time-varying bandwidths, are then supported by adjusting some multipliers, commutators, or a channel switch. These adjustments do not require hardware changes and can be performed online. However, the filter design problem is solved offline. The thesis provides various illustrative examples and it also discusses possible applications of the proposed structures in the context of other communication scenarios, e.g., cognitive radios.

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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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Arrowood, Joseph Louis Jr. "Theory and application of adaptive filter banks." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/15369.

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Leppert, Tania. "Quantization noise shaping in oversampled filter banks." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82609.

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The use of a noise-shaping system in oversampled filter banks has been shown to improve the effective resolution of subband coders. Although the filter banks directly determine the noise-shaping coefficients, a comparison between theoretical and simulated results has not been done, while the effect of the selection of the filter banks on the performance of the noise-shaping system has not yet been evaluated. Therefore, an algorithm for the generation of cosine-modulated perfect-reconstruction filter banks is presented, such that the generated filters could be used as a test bed. The optimal noise-shaping coefficients are then derived, and the noise-shaping system is inserted into the subband coder.
It is found that the theoretical results agree with the simulations, but that the performance of the noise-shaping system is limited by ill-conditioning at higher system orders. An increase in filter length and an increase in the degree of overlap between neighbouring channels contribute independently to a better performance. Also, it is seen that near-perfect reconstruction filter banks are limited by their reconstruction error but yield good results at low bitrates.

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Redif, Soydan. "Polynomial matrix decompositions and paraunitary filter banks." Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432626.

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Velazquez, Scott Richard. "Hybrid filter banks for analog/digital conversion." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10436.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
Includes bibliographical references (leaves 288-291).
by Scott Richard Velazquez.
Ph.D.

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Djokovic, Igor Vaidyanathan P. P. Vaidyanathan P. P. "Optimization issues in wavelets and filter banks /." Diss., Pasadena, Calif. : California Institute of Technology, 1995. http://resolver.caltech.edu/CaltechETD:etd-09172007-152709.

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Phoong, See-May Vaidyanathan P. P. Vaidyanathan P. P. "Time-varying and finite field filter banks /." Diss., Pasadena, Calif. : California Institute of Technology, 1996. http://resolver.caltech.edu/CaltechETD:etd-12222007-114654.

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Sodagar, Iraj. "Analysis and design of time-varying filter banks." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/13437.

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Randolph, Tami Rochele. "Image compression and classification using nonlinear filter banks." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/13439.

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Gardos, Thomas R. "Analysis and design of multidimensional FIR filter banks." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/15621.

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Alexandrou, Alexandros. "Design of filter banks for subband coding systems." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63318.

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Tsui, Kai-man, and 徐啟民. "New design methods for perfect reconstruction filter banks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30144991.

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Tay, David B. H. "Multidimensional multirate filter banks : some theory and design." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319581.

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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, Wei. "Image sequence coding using filter banks and morphological segmentation /." Lausanne : EPFL, 1994. http://library.epfl.ch/theses/?nr=1285.

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Gonzalez, Rosiles Jose Gerardo. "Image and Texture Analysis using Biorthogonal Angular Filter Banks." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5042.

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In this thesis we develop algorithms for the processing of textures and images using a ladder-based biorthogonal directional filter bank (DFB). This work is based on the DFB originally proposed by Bamberger and Smith. First we present a novel implementation of this filter bank using ladder structures. This new DFB provides non-trivial FIR perfect reconstruction systems which are computationally very efficient. Furthermore we address the lack of shift-invariance in the DFB by presenting a novel undecimated DFB that preserves the computational simplicity of its maximally decimated counterpart. Finally, we study the use of the DFB in combination with pyramidal structures to form polar-separable image decompositions. Using the proposed filter banks we develop and evaluate algorithms for texture classification, segmentation and synthesis. We perform a comparative study with other image representations and find that the DFB provides some of the best results reported on the data sets used. Using the proposed directional pyramids we adapt wavelet thresholding algorithms. We find that our decompositions provide better edge and contour preservation than the best results reported using the undecimated discrete wavelet transform. Finally, we apply the developed algorithms to the analysis and processing of synthetic aperture radar (SAR) imagery. SAR image analysis is impaired by the presence of speckle noise. Our first objective will be to study the removal of speckle to enhance the visual quality of the image. Additionally, we implement land cover segmentation and classification algorithms taking advantage of the textural characteristics of SAR images. Finally, we propose a model-based SAR image compression algorithm in which the speckle component is separated from the structural features of a scene. The speckle component is captured with a texture model and the scene component is coded with a wavelet coder at very low bit rates. The resulting decompressed images have a better perceptual quality than SAR images compressed without removing speckle.

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Waldhauser, Dirk S. [Verfasser]. "Multicarrier Systems Based on Filter Banks / Dirk S Waldhauser." Aachen : Shaker, 2009. http://d-nb.info/1159835756/34.

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Tuqan, Jamal Vaidyanathan P. P. "Statistical optimization of multirate systems and orthonormal filter banks /." Diss., Pasadena, Calif. : California Institute of Technology, 1998. http://resolver.caltech.edu/CaltechETD:etd-02042008-081232.

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Wells, Ian. "Digital signal processing architectures for speech recognition." Thesis, University of the West of England, Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294705.

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Zhang, Genzao. "Non-uniform-band digital filter banks: Design and performance analysis." Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7841.

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New design techniques of digital filter banks are presented in this thesis. The research has been focused on systematic design methods for computationally efficient filter banks with arbitrary center frequencies, which could be easily implemented and are useful in acoustic, speech signal processing, and communication systems. Frequency interpolation filter banks (FIFB) are first derived based on an adaptive filtering structure. FIFB banks show good frequency responses, interesting sensitivities and negligible parameter quantization effects and roundoff noise when they are implemented using modern DSP processors with fixed-point arithmetic. For maximally flat FIFB filter banks, the adjusted pole selection strategy by an optimization procedure is applied. Then, the resonator-based arbitrarily spaced center frequency filter banks (RFB) are proposed. They show better behaviour than general FIFB banks from the point of view of frequency responses and the implementation. In order to suppress the non-negligible sidelobes and further improve the passband performance of the non-uniform band filter banks, frequency domain windowing techniques are studied and linear programming is used to produce optimal windows for different banks. Thus the design methods of non-uniform band filter banks with windowing processing are presented and significant improvements are obtained on the filter bank performance. Finally, the FIFB filter bank techniques are successfully extended to the field of allpass and perfect reconstruction analysis/synthesis systems. This widens the application area of the FIFB filter banks. In an allpass system, a synthesis FIFB filter bank is derived based on a general analysis FIFB bank and the allpass requirement. In the perfect reconstruction system, multirate techniques are applied and the efficient general FIR synthesis filter bank and IIR FIFB filter bank are designed to construct the system.

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Davis, Craig Alton Denney Thomas Stewart. "Applications of multi-channel filter banks to textured image segmentation." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Summer/Theses/DAVIS_CRAIG_12.pdf.

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37

Park, Sang-Il. "New directional filter banks and their applications in image processing." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/13707.

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38

Duplessis-Beaulieu, François. "Multicarrier transceivers using DFT filter banks with perfect reconstruction property." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115865.

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In recent years, multicarrier modulation techniques have stirred great interest among engineers and researchers working in the field of telecommunications. Multicarrier systems are characterized by the fact that constellation symbols are modulated in parallel onto several distinct subcarriers. One specific form of multicarrier modulation, referred to as OFDM (orthogonal frequency division multiplexing), has been deployed in many applications, such as in wireless LAN (local area network) routers, in high-definition television tuners, and in DSL (digital subscriber line) modems. Multicarrier and OFDM systems have proved to be much more robust against impairments such as impulse noise and sudden channel fadings than their single carrier counterparts. Moreover, channel equalization in OFDM systems can be performed at a very low computational cost by a set of per-subcarrier one-tap equalizers.
Despite their many advantages, OFDM systems have a few, but important, drawbacks. In particular, OFDM relies on the inverse FFT for modulation purposes, which leads to a very poor spectral containment and a high susceptibility to narrowband noise. To mitigate this problem, we propose in this thesis to perform multicarrier modulation using a perfect reconstruction (PR) DFT filter bank instead of employing the inverse FFT. The design of such filter banks is addressed using a novel method that guarantees the PR property to be satisfied while the spectral containment is being maximized. Equalization in the proposed DFT filter bank transceiver takes advantage of the fact that the filter banks do not contribute to any distortion due to its PR nature. Two equalization schemes are presented. The first one is based on a zero-padded block linear equalization approach, and the second one utilizes a one-tap per subcarrier configuration. The estimation of the channel coefficients in the proposed transceiver is also addressed. A blind estimation method that exploits the inherent cyclostationarity of the transmitted signal is derived. Computer experiments presented in this thesis indicate that the spectral containment of the proposed PR DFT filter bank transceiver is indeed superior to that of the OFDM system. Moreover, simulations conducted in a DSL-like environment contaminated by a narrowband noise show that the achievable bit rate of the proposed transceiver is much higher than that of a conventional OFDM system.

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39

何文泳 and Man-wing Ho. "Non-uniform filter banks and context modeling for image coding." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B3122605X.

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Chen, Ying-Jui 1972. "Wavelets and multirate filter banks : theory, structure, design, and applications." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30140.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.
Includes bibliographical references (p. 219-230) and index.
Wavelets and filter banks have revolutionized signal processing with their ability to process data at multiple temporal and spatial resolutions. Fundamentally, continuous-time wavelets are governed by discrete-time filter banks with properties such as perfect reconstruction, linear phase and regularity. In this thesis, we study multi-channel filter bank factorization and parameterization strategies, which facilitate designs with specified properties that are enforced by the actual factorization structure. For M-channel filter banks (M =/> 2), we develop a complete factorization, M-channel lifting factorization, using simple ladder-like structures as predictions between channels to provide robust and efficient implementation; perfect reconstruction is structurally enforced, even under finite precision arithmetic and quantization of lifting coefficients. With lifting, optimal low-complexity integer wavelet transforms can thus be designed using a simple and fast algorithm that incorporates prescribed limits on hardware operations for power-constrained environments. As filter bank regularity is important for a variety of reasons, an aspect of particular interest is the structural imposition of regularity onto factorizations based on the dyadic form uvt. We derive the corresponding structural conditions for regularity, for which M-channel lifting factorization provides an essential parameterization. As a result, we are able to design filter banks that are exactly regular and amenable to fast implementations with perfect reconstruction, regardless of the choice of free parameters and possible finite precision effects. Further constraining u = v ensures regular orthogonal filter banks,
(cont.) whereas a special dyadic form is developed that guarantees linear phase. We achieve superior coding gains within 0.1% of the optimum, and benchmarks conducted on image compression applications show clear improvements in perceptual and objective performance. We also consider the problem of completing an M-channel filter bank, given only its scaling filter. M-channel lifting factorization can efficiently complete such biorthogonal filter banks. On the other hand, an improved scheme for completing paraunitary filter banks is made possible by a novel order-one factorization which allows greater design flexibility, resulting in improved frequency selectivity and energy compaction over existing state of the art methods. In a dual setting, the technique can be applied to transmultiplexer design to achieve higher-rate data transmissions.
by Ying-Jui Chen.
Ph.D.

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41

Ho, Man-wing. "Non-uniform filter banks and context modeling for image coding /." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23736008.

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42

Ha, Hoang Kha Electrical Engineering &amp 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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43

Tufan, Emir. "Multisubband structures and their application to image processing." Thesis, London South Bank University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245140.

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Pérez, Tejada Natalia. "Cosine Modulated Filter Banks Systems in the Presence of Multipath Transmission." Thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9651.

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45

Florêncio, Dinei Alfonso Ferreira. "A new sampling theory and a framework for nonlinear filter banks." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/15792.

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46

陳志榮 and Chi-wing Chan. "Design of 1-D and 2-D perfect reconstruction filter banks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31214915.

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47

Xie, Xuemei, and 謝雪梅. "New design and realization methods for perfect reconstruction nonuniform filter banks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31246175.

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48

Sezen, Umut. "Anticausal inverses for IIR filter banks, quincunx wavelets and image coding." Thesis, University of Warwick, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397219.

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49

Yan, Jie. "Designs of orthogonal filter banks and orthogonal cosine-modulated filter banks." Thesis, 2010. http://hdl.handle.net/1828/2647.

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This thesis investigates several design problems concerning two-channel conjugate quadrature (CQ) filter banks and orthogonal wavelets, as well as orthogonal cosine-modulated (OCM) filter banks. It is well known that optimal design of CQ filters and wavelets and optimal design of prototype filters (PFs) of OCM filter banks in the least squares (LS) or minimax sense are nonconvex problems and to date only local solutions can be claimed. In this thesis, we first make some improvements over several direct design techniques for local design problems in terms of convergence and solution accuracy. By virtue of the recent progress in global polynomial optimization and the improved local design methods mentioned above, we describe an attempt at developing several design strategies that may be viewed as our endeavors towards global solutions for LS CQ filter banks, minimax CQ filter banks, and OCM filter banks. In brief terms, the proposed design strategies are based on several observations made among globally optimal impulse responses of low-order filter banks, and are essentially order-recursive algorithms in terms of filter length combined with some techniques in identifying a desirable initial point in each round of iteration. This main idea is applied to three design scenarios in this thesis, namely, LS design of orthogonal filter banks and wavelets, minimax design of orthogonal filter banks and wavelets, and design of orthogonal cosine-modulated filter banks. Simulation studies are presented to evaluate and compare the performance of the proposed design methods with several well established algorithms in the literature.

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50

Chen, Charng-Kann, and 陳常侃. "Optimal Design of Digital Filters and Digital Filter Banks." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/60246289762306954645.

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博士
國立臺灣大學
電機工程研究所
82
The work of this dissertation is to devise novel and efficient techniques for optimally designing one-dimensional (1-D) digital filters, two-dimensional (2-D) digital filters, 1-D multirate filter banks, and 2-D multirate filter banks in the appropriate optimal sense. As for the 1-D digital filters, the proposed techniques include the design algorithms for designing quasi-equiripple FIR and IIR digital filters, discrete coefficient FIR digital filters with arbitrary amplitude and phase response, digital all-pass filters, high order digital differentiators using $L_{1}$ error criteria, sharp FIR digital filters with prescribed group delay phase response, and cascade form FIR digital filters with powers-of-two coefficients in the complex domain, and Chebyshev design of IIR digital filters with arbitrary magnitude and phase responses. On the other hand, this dissertation also presents two approaches for equiripple design of 2-D linear-phase FIR digital filters. One approach is based on a novel minimax design method and the other approach is the McClellan transform based design techniques. With regard to the 1-D filter bank systems, a deep study of designing quadrature mirror filters (QMF) with linear phase in the frequency domain using different optimal criteria is given. The powers-of-two coefficient design of QMF bank is considered, too. Other than the uniform-division QMF banks, the design of two-channel nonuniform-division maximally decimated filter banks is thoroughly studied. Considering the design of 2-D multirate filter bank systems, a novel minimax design of 2-D nonseparable QMF banks with non-diagonal decimation/ expansion matrix is presented. It is shown that the quincunx QMF bank and the parallelogram QMF bank can be easily designed using the method.

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Dissertations / Theses on the topic 'Filter banks'

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