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1
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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Khumsat, Phanumas. "Transition frequency integration : technique for high frequency continuous-time filters." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398200.
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Tingleff, Jens. "Current Mode Wave Active Filters : a topology for high frequency integrated filters." Thesis, Imperial College London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337669.
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Köroğlu, Mustafa Hadi. "High frequency integrated filters for wireless applications." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/14458.
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Mahattanakul, Jirayuth. "High frequency, low distortion current-mode filters." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300970.
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Phudpong, Padisan. "Nonlinear microwave filters for frequency selective limiting." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487749.
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This thesis presents a new method for suppressing interfering signals in wideband microwave receivers, such as electronic support measure (ESM) systems. ESM systems operate over a wide dynamic range and RF bandwidth in a dense signal environment, where large amplitude interfering signals of unknown frequency make it difficult to detect and identify signals of interest.
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Kula, Jeffrey Scott. "Reconfigurable Band Rejection Frequency Selective Structures." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1545336272765337.
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Ribner, David B. (David Byrd) Carleton University Dissertation Engineering Electrical. "Design considerations for high-frequency switched-capacitor filters." Ottawa, 1985.
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10
Greer, N. P. J. "The design of high frequency transconductor ladder filters." Thesis, University of Edinburgh, 1992. http://hdl.handle.net/1842/14951.
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A brief survey of filter technologies is given and the requirement for a high frequency continuous time monolithic filtering capability is identified. The ideal transconductor is defined and is compared to the other most common forms of integrated amplifier. A distinction is drawn between 'open loop' and 'closed loop' transconductor integrators. Although closed loop integrators have several advantages, filters using open loop integrators are emphasised since they have greater potential for high frequency operation. A detailed review is given of transistor level transconductor circuits in CMOS, JFET, GaAs MESFET and bipolar technologies, proposed by other researchers. Also reviewed are the techniques that have been used for the design of transconductor filters including automatic frequency and phase tuning circuits. It is demonstrated that standard methods for active-RC and switched capacitor ladder filter design are not satisfactory when applied to transconductor ladder design, particularly for bandpass responses. An original CMOS transconductance cell is described which is well suited to applications requiring high frequency of operation and high linearity within a low power supply. The advantages of designing transconductors with folded cascade ouput stages are demonstated. Also, two enhancements to the standard folded cascade structure are proposed. The first is the addition of low impedance inputs (in addition to the normal inputs). These allow the use of unidirectional capacitive branches in filters based upon open loop integrators, and thereby increase greatly the number of ladder filter structures that can be designed. The second enhancement provides control of the phase response of the transconductor by means of a variable d.c. voltage. This may be used to compensate actively for the effects of parasitic poles. A set of algebraic methods for the design of transconductor ladder filters is presented. These represent a structured method which may be used as the basis for computer aided design tools. More importantly they provide an abstract representation of the ladder which can be used to find superior active filter circuits that are not intuitively obvious. In particular, new circuits for bandpass ladders are derived which could not be obtained using conventional methods. Applying the developments described above, a set of transconductor ladder filters and a frequency control loop have been designed and fabricated on a 1 micron CMOS process. These include 1 MHz lowpass filters, along with 400 KHz and 1 MHz bandpass filters. Detailed experimental results are given for these circuits.
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Bronec, David. "Kmitočtové filtry řízené mikroprocesory." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-221239.
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This thesis is focused on the microprocessor-controlled frequency filter project. The main goal of the thesis is to present basic terms and principles of frequency filters and active frequency filters for cascading synthesis. Furthermore, the work contains information on digital potentiometers. The thesis includes circuit simulations and a project of connecting with a printed circuit board. The last chapter contains the results of the measurements.
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Tang, Weiran. "Frequency merging for demosaicking /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?ECED%202009%20TANGW.
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Mohsén, Mikael. "Implementation and Evaluation of Single Filter Frequency Masking Narrow-Band High-Speed Recursive Digital Filters." Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1522.
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In this thesis two versions of a single filter frequency masking narrow-band high-speed recursive digital filter structure, proposed in [1], have been implemented and evaluated considering the maximal clock frequency, the maximal sample frequency and the power consumption. The structures were compared to a conventional filter structure, that was also implemented. The aim was to see if the proposed structure had some benefits when implemented and synthesized, not only in theory. For the synthesis standard cells from AMS csx 0.35 mm CMOS technology were used.
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Lewinski, Komincz Artur Juliusz. "High frequency and high dynamic range continuous time filters." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5933.
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Many modern communication systems use orthogonal frequency division
multiplexing (OFDM) and discrete multi-tone (DMT) as modulation schemes where
high data rates are transmitted over a wide frequency band in multiple orthogonal subcarriers.
Due to the many advantages, such as flexibility, good noise immunity and the
ability to be optimized for medium conditions, the use of DMT and OFDM can be found
in digital video broadcasting, local area wireless network (IEEE 802.11a), asymmetric
digital subscriber line (ADSL), very high bit rate DSL (VDSL) and power line
communications (PLC). However, a major challenge is the design of the analog frontend;
for these systems a large dynamic range is required due to the significant peak to
average ratio of the resulting signals. In receivers, very demanding high-performance
analog filters are typically used to block interferers and provide anti-aliasing before the
subsequent analog to digital conversion stage. For frequencies higher than 10MHz, Gm-C filter implementations are generally
preferred due to the more efficient operation of wide-band operational transconductance
amplifiers (OTA). Nevertheless, the inherent low-linearity of open-loop operated OTA
limits the dynamic range. In this dissertation, three different proposed OTA linearity
enhancement techniques for the design of high frequency and high dynamic range are
presented. The techniques are applied to two filter implementations: a 20MHz second
order tunable filter and a 30MHz fifth order elliptical low-pass filter. Simulation and
experimental results show a spurious free dynamic range (SFDR) of 65dB with a power
consumption of 85mW. In a figure of merit where SFDR is normalized to the power
consumption, this filter is 6dB above the trend-line of recently reported continuous time
filters.
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Johnstone, G. G. "An investigation into filters utilising coupled transmission lines." Thesis, University of Surrey, 1995. http://epubs.surrey.ac.uk/844257/.
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This thesis addresses itself to the solution of a number of problems which arise in the development of Radio Frequency filters, particularly those involving coupled transmission lines as resonant elements. The text is divided into a number of sections dealing with individual topics. After a brief description of Darlington filter design principles, there is an account of the pivotal role of quarter wave sections and their vital part in the realisation of high frequency filters. This is followed by the development of new material relating to equivalent circuits of physical lines in terms of quarter wave sections, and its application to improvements in the design of wide-band filters. There follows an account of a new procedure for calculating the dimensions of comb-line and inter-digital filters. This section includes a new proposal for the inversion of Getsinger's procedure to permit the calculation of rectangular rod dimensions and spacings from given electrical data. There is also an algorithm for use with round rods which circumvents the tedious manual interpolation procedure devised by Cristal. There follows an investigation of and a proposed solution to a long-known but unexplained discrepancy existing between the calculated and measured pass-band width of the class of comb-line filters. With the new procedure the discrepancy reported previously to be of the order of 10% is eliminated. Finally, experimental evidence is adduced to verify the algorithms outlined in the preceding chapters.
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Daaboul, Adel Afif. "Active filters for application into the medium-frequency band." Thesis, University of Bradford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304183.
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Adlard, Jonathan F. "Frequency shift filtering for cyclostationary signals." Thesis, University of York, 2000. http://etheses.whiterose.ac.uk/14178/.
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The frequency-shift (FRESH) filter is a structure which exploits the spectral correlation of cyclostationary signals for removing interference and noise from a wanted signal. As most digital communication signals are cyclostationary, FRESH filtering offers certain advantages for interference rejection in a communications receiver. This thesis explores the operation and application of FRESH filters in practical interference scenarios. The theoretical background to cyclostationarity is clarified with graphical interpretations of what cyclostationarity is, and how a FRESH filter exploits it to remove interference. The effects of implementation in a sampled system are investigated, in filters which use baud rate related cyclostationarity, leading to efficiency improvements. The effects of varying the wanted signal pulse shape to enhance the cyclostationarity available to the FRESH filter are also investigated. A consistent approach to the interpretation of the FRESH filter's operation is used throughout, while evaluating the performance in a wide range of realistic channel conditions. VLF radio communication is proposed as one area where interference conditions are particularly suitable for the use of FRESH filtering. In cases of severe adjacent channel interference it is found that a FRESH filter can almost completely remove the interferer. The effects of its use with an impulse rejection technique are also investigated. Finally, blind adaptation of FRESH filters through exploitation of carrier related cyclostationarity is investigated. It is found that one existing method loses the advantage of FRESH filtering over time invariant linear filtering. An improvement is proposed to the latter which restores its performance to that of a trained FRESH filter, and also reveals that carrier related cyclostationarity can be exploited, in some cases, by a simpler method. J.
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Peng, Su. "Design and analysis of FIR filters based on Matlab." Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-26759.
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In digital control system, interference, which is mixed in the input signal, has a great influence on the performance of the system. Therefore, processing of input signal has to be done to get useful signal. Finite impulse response (FIR) filter plays an important role in the processing of digital signal. Designing the FIR filter by Matlab can simplify the complicated computation in simulation and improve the performance. By using the methods of window function, frequency sampling and convex optimization techniques, the design of FIR filter has been processed by Matlab. In the view of the designed program of Matlab and I can get the amplitude-frequency characterization. By using the FIR digital filters which have been designed to process the input signal based on the Matlab function, the filtering effect of different digital filters is analyzed by comparing the signal’s amplitude-frequency diagrams which have been generated. The experimental results show that the FIR filters designed in this paper are effective.
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Clayton, Heather Julie. "Digital frequency tracking algorithms for dynamic Doppler shift environments." Thesis, King's College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282771.
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Kumar, Ajay. "A wide dynamic range high-q high-frequency bandpass." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28126.
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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.Committee Chair: Allen Phillip; Committee Member: Hasler Paul; Committee Member: Keezer David; Committee Member: Kenny James; Committee Member: Pan Ronghua.
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Lin, Fang. "High-Q high-frequency CMOS bandpass filters for wireless applications." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/14869.
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Su, Hsiao Wei. "Design and performance of high-frequency CMOS-OTA-C filters." Thesis, University of Hertfordshire, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251521.
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Moritz, James Rudolph. "Design and tuning of high frequency integrated continuous-time filters." Thesis, University of Hertfordshire, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427577.
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Perodou, Arthur. "Frequency design of passive electronic filters : a modern system approach." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEC046.
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L’explosion actuelle du nombre d’appareils connectés (smartphones, drones, IoT, …) et du volume des données à transmettre engendre une croissance exponentielle du nombre de bandes radiofréquences. Toutes les solutions élaborées pour faire face à cette demande croissante, telle que l’agrégation de porteuses, impliquent de concevoir des filtres fréquentiels satisfaisant des contraintes (performance, consommation d’énergie, coût, …) toujours plus strictes. Les filtres passifs AW, pour acoustic wave (AW) en anglais, semblant être les seuls pouvant satisfaire ces contraintes. Cependant, face à l’augmentation drastique de la complexité de leur problème de conception, les méthodes traditionnelles de conception apparaissent limitées. Il devient donc nécessaire de développer de nouvelles méthodes, qui soient systématiques et efficaces d’un point de vue algorithmique. Le problème de synthèse des filtres AW est une instance du problème de synthèse de filtres électroniques passifs, intrinsèquement lié aux origines de la théorie des Systèmes linéaires et de l’Automatique. Des méthodes systématiques ont été développées pour des cas particuliers, tels que les filtres LC-échelle, mais n’incluent pas les filtres AW. Notre but est donc de les revisiter et de les généraliser en utilisant une approche systémique moderne, afin d’obtenir une méthodologie systématique et efficace de conception de filtres électroniques passifs, avec un intérêt particulier pour les filtres AW. Pour ce faire, le paradigme de l’optimisation convexe, et particulièrement la sous-classe nommée optimisation LMI, nous paraît être un candidat naturel. Doté de solveurs efficaces, il permet de résoudre un large éventail de problèmes d’ingénierie en un faible temps de calcul. Afin de relier notre problème de conception à cet environnement, il est proposé d’utiliser des outils modernes tels que la représentation LFT et la caractérisation mathématique dite de dissipativité. Historiquement, deux approches de conception se sont opposées. La première consiste à faire varier les valeurs caractéristiques des composants jusqu’à satisfaction du gabarit fréquentiel. Bien que flexible et proche de la formulation originelle du problème, cette approche aboutit typiquement à un problème d’optimisation complexe. Notre première contribution est d’avoir révélé les sources de cette complexité ainsi que de les avoir considérablement réduites, en introduisant une représentation originale qui résulte de la combinaison de l’outil LFT et du formalisme des Systèmes Hamiltoniens à Ports. Un algorithme résolvant séquentiellement des problèmes LMIs est proposé, possédant un taux de convergence raisonnable si le point initial est bien choisi. La seconde approche se compose de deux étapes. Une fonction de transfert est d’abord synthétisée de façon à satisfaire le gabarit fréquentiel. Cette étape correspond à un problème classique d’Automatique et de Traitement du Signal qui peut être efficacement résolu via l’optimisation LMI. Puis, cette fonction de transfert est réalisée comme un circuit avec une topologie donnée. Pour cela, elle doit satisfaire des conditions de réalisation. Ces dernières ne peuvent pas toutes être inclues dans la première étape, et nous formalisons certaines pratiques courantes pour en considérer le plus possible. Cela nous mène à résoudre le problème général de synthèse fréquentielle de filtres LFT. Notre seconde contribution est d’avoir fourni des méthodes de synthèse efficaces, à base d’optimisation LMI, pour résoudre certains sous-problèmes. Cela est accompli en généralisant la technique de la factorisation spectrale conjointement avec l’utilisation des extensions du Lemme KYP. Pour certains filtres électroniques passifs, comme les filtres LC-échelle passe-bande, la seconde approche permet de résoudre efficacement le problème de conception associé. Plus généralement, elle procure un point initial à la première approche, comme illustré dans le cas d’un filtre AWThe current explosion of communicating devices (smartphones, drones, IoT...), along with the ever-growing data to be transmitted, produces an exponential growth of the radiofrequency bands. All solutions devised to handle this increasing demand, such as carrier aggregation, require to synthesise frequency filters with stringent industrial requirements (performance, energy consumption, cost ...). While the technology of acoustic wave (AW) resonators, that seem to be the only passive micro-electronic components available to fulfil these requirements, is mature, the associate design problem becomes dramatically complex. Traditional design methods, based on the intuition of designers and the use of generic optimisation algorithms, appear very limited to face this complexity. Thus, systematic and efficient design methods need to be developed. The design problem of AW filters happens to be an instance of the more general design problem of passive electronic filters, that played an important role in the early development of Linear Control and System theory. Systematic design methods were developed in particular cases, such as for LC-ladder filters, but do not enable to tackle the case of AW filters. Our aim is then to revisit and generalise these methods using a modern System approach, in order to develop systematic and efficient design methods of passive electronic filters, with a special focus on AW filters. To achieve this, the paradigm of convex optimisation, and especially the sub-class of Linear Matrix Inequality (LMI) optimisation, appears for us a natural candidate. It is a powerful framework, endowed with efficient solvers, able to optimally solve a large variety of engineering problems in a low computational time. In order to link the design problem with this framework, it is proposed to use modern tools such as the Linear Fractional Transformation (LFT) representation and a mathematical characterisation coming from Dissipative System theory. Reviewing the different design methods, two design approaches stand out. The first approach consists in directly tuning the characteristic values of the components until the frequency requirements are satisfied. While very flexible and close to the original problem, this typically leads to a complex optimisation problem with important convergence issues. Our first main contribution is to make explicit the sources of this complexity and to significantly reduce it, by introducing an original representation resulting from the combination of the LFT and the Port-Hamiltonian Systems (PHS) formalism. A sequential algorithm based on LMI relaxations is then proposed, having a decent convergence rate when a suitable initial point is available. The second approach consists of two steps. First, a transfer function is synthesised such that it satisfies the frequency requirements. This step is a classical problem in Control and Signal Processing and can be efficiently solved using LMI optimisation. Second, this transfer function is realised as a passive circuit in a given topology. To this end, the transfer function needs to satisfy some conditions, namely realisation conditions. The issue is to get them with a convex formulation, in order to keep efficient algorithms. As this is generally not possible, an idea is to relax the problem by including common practices of designers. This leads to solve some instances of a general problem denoted as frequency LFT filter synthesis. Our second main contribution is to provide efficient synthesis methods, based on LMI optimisation, for solving these instances. This is achieved by especially generalising the spectral factorisation technique with extended versions of the so-called KYP Lemma. For particular electronic passive filters, such as bandpass LC-ladder filters, this second approach allows to efficiently solve the design problem. More generally, it provides an initial point to the first approach, as illustrated on the design of a particular AW filter
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Lessing, Maurice. "Ultra-low-noise frequency synthesis, comparison and dissemination using femtosecond optical frequency combs." Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/8514.
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This thesis presents research into ultra-low noise photonic microwave synthesis and the development of a novel, frequency comb-based, fibre optic time transfer technique. The focus in the first area is on reducing the noise introduced in the optical-to- electrical conversion process using balanced optical-microwave phase detectors. Two mainly free-space and two mainly fibre-based devices were built and their performance was characterised. The phase noise of the optical-to-electrical conversion of the free-space device was -119 dBc Hz⁻¹ at 1 Hz and -143 dBc Hz⁻¹ at 20 kHz from an 8 GHz carrier which is the best performance reported for a free-space balanced-optical microwave phase detector. The improved fibre-based set-ups demonstrated a state-of-the-art amplitude-to-phase noise suppression of 60 dB and a phase noise of the optical-to-electrical conversion of -131 dBc Hz⁻¹ at 1 Hz and 148 dBc Hz⁻¹ at 20 kHz from an 8 GHz carrier. The novel time transfer technique developed in the second part superimposes timing information onto the optical pulse train of an ITU-channel-filtered frequency comb using an intensity modulation scheme. Time transfer over a 50 km long, delay-stabilised fibre spool produced a state-of-the-art time deviation of 300 fs and an accuracy of approximately 0.01 ns which is close to the best performance achieved using amplitude modulated cw lasers. Using this technique on a 159 km long installed fibre link between NPL and Reading, the same time deviation was achieved and an accuracy of approximately 0.08 ns was obtained, limited by uncertainty of the time interval counter. Using the same fibre link, microwave frequency transfer of the ITU-channel-filtered comb was demonstrated with a fractional frequency instability of 2x10⁻¹⁷ at 5000 s which is approximately at the same level as the best previously reported results which were obtained with a 30 nm wide optical frequency comb.
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Palomo, Timothy Joseph. "Microfluidically Reconfigurable Frequency-Agile RF Filters with Wide Frequency Tuning Range and High Power Handling Capability." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6124.
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Radio Frequency (RF) filters are among the key components of today’s multifunctional devices and test equipment. However, the multifuctionality need significantly drives the required filter number and causes large areas to be allocated for filters. To alleviate this issue, over the recent years, reconfigurable filters have been proposed as an attractive alternative. Nevertheless, existing reconfigurable filter technologies demonstrate degraded performances in terms of loss, frequency tunability bandwidth, and power handling capability. This work investigates, for the first time, microfluidic based reconfiguration techniques for implementation of RF bandpass filters. Specifically, microfluidics is shown to provide mechanisms for achieving compact RF bandpass filters that can exhibit low loss, high power handling, and high frequency tunability. First, we present the utilization of liquid metals for realization of a frequency-agile microstrip bandpass filters consisting of broadside coupled split ring resonator (BC-SRR). In this design approach, one of the loops of the BC-SRR is realized from liquid metal to be able to microfluidically change the resonator shape and associated resonance frequency. The filter exhibits a 29% frequency tunable range from 870 MHz to 650 MHz, with insertion loss <3 >dB, over the entire frequency tuning range, for a fractional bandwidth (FBW) of 5%. To the best of our knowledge, this filter design is the first in available literature that shows a continuously frequency reconfigurable microfluidic RF band-pass filter. To overcome the oxidization and lower conductivity issues associated with liquid metals and enhance the frequency tuning range further, subsequently, we introduce a filter design technique in which microfluidically repositionable metallized plates are utilized within microfluidic channels with ultra-thin insulator walls. Specifically, this technique is employed to design a two pole microstrip bandpass filter where microfluidically repositionable metalized plates are used to capacitively load printed open loop resonators. To operate the filter (and control movement of multiple metalized plates) with a single bi-directional micropump unit, a strategically designed meandered microfluidic channel is implemented. The filter exhibits a 50% tuning range (from 1.5 GHz to 0.9 GHz), with an insertion loss15 W input power without the need of thick ground planes and/or heat sinks.
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Piskin, Hatice. "Design And Implementation Of Fir Digital Filters With Variable Frequency Characteristics." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606853/index.pdf.
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Variable digital filters (VDF) find many application areas in communication, audio, speech and image processing. This thesis analyzes design and implementation of FIR digital filters with variable frequency characteristics and introduces two design methods. The design and implementation of the proposed methods are realized on Matlab software program. Various filter design examples and comparisons are also outlilned. One of the major application areas of VDFs is software defined radio (SDR). The interpolation problem on sample rate converter (SRC) unit of the SDR is solved by using these filters. Realizations of VDFs on SRC are outlined and described. Simulations on Simulink and a specific hardware are examined.
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Masood-ul-Hasan. "Design and test of high-frequency CMOS integrated OTA-C filters." Thesis, University of Hertfordshire, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440161.
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Zhang, Hui. "The investigation of correlator systems utilizing object and frequency space filters." Thesis, Abertay University, 2000. https://rke.abertay.ac.uk/en/studentTheses/5afbbda6-0d84-471b-bfcd-f3717c905233.
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The aim of this research is to develop real-time object recognition systems which are robust and have good discrimination. An important aspect of this work is the development of a rotationally invariant optical correlator. Optical correlation systems are investigated for the purpose of high speed, high discriminant and distortion invariant pattern recognition. A photorefractive joint transform correlator (JTC) using Bismuth Silicon Oxide (BSO) as a non-linear recording medium and a liquid crystal television as a spatial light modulator is implemented. The underlying physics is considered, some specific techniques to improve the operation are proposed. The properties of photorefractive BSO are investigated for use as the dynamic holographic recording medium in information processing systems. The moving grating technique is used for edge-enhanced image reconstruction and for making the correlation peak sharper. The object and frequency space filtering methods are presented to improve the correlation performance, the discrimination, and to realise distortion invariant pattern recognition. Circular harmonic matched filters and phase-only filters with different expansion orders are involved in the photorefractive JTC for real-time rotationally invariant pattern recognition. These filters can also be used to track an object with different orientations. The coherent triple joint transform correlator employs a third beam to modify the Fourier spectrum and hence improves the correlation performance. In the incoherent triple JTC, the wavelet transform is used in the Fourier domain to achieve a high signalto-noise ratio, noise robustness as well as discrimination. Several wavelet functions are also used, after processing, in the conventional JTC for high-speed image feature extraction. The wavelet transform functions can also be used in the JTC with circular harmonic filters to improve the output quality of rotation invariant pattern recognition.
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Kardoulaki, Evdokia. "CMOS Hyperbolic-Sine ELIN filters for low/audio frequency biomedical applications." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9612.
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Hyperbolic-Sine (Sinh) filters form a subclass of Externally-Linear-Internally-Non-Linear (ELIN) systems. They can handle large-signals in a low power environment under half the capacitor area required by the more popular ELIN Log-domain filters. Their inherent class-AB nature stems from the odd property of the sinh function at the heart of their companding operation. Despite this early realisation, the Sinh filtering paradigm has not attracted the interest it deserves to date probably due to its mathematical and circuit-level complexity. This Thesis presents an overview of the CMOS weak inversion Sinh filtering paradigm and explains how biomedical systems of low- to audio-frequency range could benefit from it. Its dual scope is to: consolidate the theory behind the synthesis and design of high order Sinh continuous–time filters and more importantly to confirm their micro-power consumption and 100+ dB of DR through measured results presented for the first time. Novel high order Sinh topologies are designed by means of a systematic mathematical framework introduced. They employ a recently proposed CMOS Sinh integrator comprising only p-type devices in its translinear loops. The performance of the high order topologies is evaluated both solely and in comparison with their Log domain counterparts. A 5th order Sinh Chebyshev low pass filter is compared head-to-head with a corresponding and also novel Log domain class-AB topology, confirming that Sinh filters constitute a solution of equally high DR (100+ dB) with half the capacitor area at the expense of higher complexity and power consumption. The theoretical findings are validated by means of measured results from an 8th order notch filter for 50/60Hz noise fabricated in a 0.35μm CMOS technology. Measured results confirm a DR of 102dB, a moderate SNR of ~60dB and 74μW power consumption from 2V power supply.
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Kiani, Ghaffer I. "Passive, active and absorbing frequency selective surfaces for wireless communication applications." Phd thesis, Australia : Macquarie University, 2008. http://hdl.handle.net/1959.14/76611.
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Delaney, Eamon John. "Harmonic and interharmonic current distortion in variable frequency synchronous motor drives." Thesis, Staffordshire University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282140.
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Machibya, Telesphory Raphael. "Design and compensation of high-frequency, narrow-band, bandpass MOSFET-C filters." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185075.
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Circuit designs that employ only CMOS technology are becoming more desirable than those using traditional bipolar integrated circuit technology. This technology offers a high density of MOS circuitry, good capacitor accuracy and high stability. The availability of techniques for the design and realization of precision filters in fully integrated form has many applications in signal processing VLSI circuits. The design, simulation and compensation of MOS transistor filters are presented. The MOS transistor is used as a voltage controlled resistor. The resulting "MOSFET-C" filters can then be built of MOS transistors, capacitors and operational amplifiers fabricated in MOS technology. The advantages of MOSFET-C filters over other integrated filters are discussed. Desirable MOS transistor circuit configurations for use in these filter designs are also presented. High-order, high-frequency, narrow-band bandpass filters are designed and simulated to give a systematic step-by-step design procedure for realizing MOSFET-C filters. These steps include modifying existing well established and studied filter building blocks for use in this method. The nonidealities associated with MOS transistors, especially at high frequencies, are studied and modeled for simulation. Compensation techniques for these nonidealities, together with those of operational amplifiers are presented and applied to both RC and MOSFET-C filters. A compensation scheme is developed which cancels the op amp effects in second-order filter building blocks.
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Xiao, Haiqiao. "Design of Radio-Frequency Filters and Oscillators in Deep-Submicron CMOS Technology." PDXScholar, 2008. https://pdxscholar.library.pdx.edu/open_access_etds/5233.
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Radio-frequency filters and oscillators are widely used in wireless communication and high-speed digital systems, and they are mostly built on passive integrated inductors, which occupy a relative large silicon area. This research attempted to implement filters and oscillators operating at 1-5 GHz using transistors only, to reduce the circuits’ area. The filters and oscillators are designed using active inductors, based on the gyrator principle; they are fabricated in standard digital CMOS technology to be compatible with logic circuits and further lower the cost. To obtain the highest operating frequency, only parasitic capacitors were used.
Two new active-inductor circuits are derived from this research, labeled allNMOS and all-NMOS-II. The all-NMOS active inductor was used to design high-Q bandpass filters and oscillators, which were fabricated in TSMC’s 0.18-µm digital CMOS process. The highest center frequency measured was 5.7 GHz at 0.20-µm gate length and the maximum repeatably measured Q was 665. 2.4-GHz circuits were also designed and fabricated in 0.40-µm gate length. The all-NMOS-II circuit has superior linearity and signal fidelity, which are robust against process and temperature variations, due to its novel structure. It was used in signal drivers and will be fabricated in commercial products.
Small-signal analysis was conducted for each of the active-inductor, filter and oscillator circuits, and the calculated performance matches those from simulations. The noise performance of the active inductor, active-inductor filter and oscillator was also analyzed and the calculated results agree with simulations. The difference between simulation and measured results is about 10% due to modeling and parasitic extraction error.
The all-NMOS active-inductor circuit was granted a US patent. The US patent for all-NMOS-II circuit is pending. This research generated three conference papers and two journal papers.
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Cooper, Simon. "A frequency response method for sensor suite selection with an application to high-speed vehicle navigation." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318591.
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Hay, Nicole M. "Complex Filters as Cascade of Buffered Gingell Structures: Design from Band-Pass Constraints." DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1731.
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Complex filters are multi-input, multi-output networks designed to discriminate based upon the relative phase difference between input signals. Complex filters find application in modern wireless systems for single sideband transmission and image-reject reception. This thesis presents one active complex filter implementation using two operational amplifiers per stage, termed “type-II” topology. The “type-II” originates from the passive RC-CR polyphase topology presented by Gingell in his 1973 paper, “Single sideband modulation using sequence asymmetric polyphase networks.” This new topology gains several advantages over existing complex filter implementations, namely “cascadability” (multiple sections placed in series to create a higher-order response) without altering the characteristics of each individual stage. In addition to describing the derivation of the topology and its performance relative to existing topologies, this thesis investigates the passband characteristics of a general higher-order filter and provides a passband-centric design approach through derivations of closed form expressions for passband gain and bandwidth. The thesis includes a five-stage design example using this approach in addition to an implementation, its characterization, and its comparison to the derived expressions and simulations.
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O'Carroll, A. P. "A study of the higher-frequency performance of operational-amplifier analogue filters : active-RC and active-R filter sections using integrated operational amplifiers are investigated up to the medium frequency communications band by consideration of." Thesis, University of Bradford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235719.
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Oksar, Irfan. "Design And Realization Of Mixed Element Broadband Bandpass Filters." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/4/1092964/index.pdf.
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In this thesis, a highly selective broadband hybrid bandpass filter operating between 0.4-2.0 GHz with a stopband up to 7 GHz is designed and analyzed. The realization is carried out by hybrid method, which combines both lumped and distributed element filters. In this approach, two separate filters, which are lumped highpass with 0.4 GHz corner frequency and distributed stripline lowpass with 2 GHz corner frequency, are combined to get the bandpass filter that has a passband in between 0.4 to 2.0 GHz. The usage of the lumped elements for the highpass filter resulted in a great size reduction compared to distributed element approach. The design software FILPRO&tradeis used to synthesize the trial filters. More than forty filters are synthesized, and among them, the ones that have better properties are chosen for further processes. Optimization, modeling and electromagnetic simulations of the selected lumped and distributed filters are carried out on the software GENESYS&trade
. Distributed filters are also simulated using the software SONNET&trade
. After the simulations, all of the simulated filters are realized and measured, and the level of consistency with the simulations is observed. According to the results of the measurements, the filter combination that has the best combination of low insertion loss, small dimensions, high stopband attenuation and low spur levels is selected for the final bandpass filter structure and a few variants are examined to get the final structure.
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Cederström, Love. "Power Efficient Digital Decimation Filters for Sigma-Delta ADCs." Thesis, Linköping University, Department of Electrical Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51464.
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The development of integrated circuit technology seen in the last decades has enabled a large variety of battery operated equipment to emerge, such as smallsensors and medical implants. These applications often has low requirements on sampling frequency but require a very low power consumption to achieve a longbattery life.
This thesis investigates one aspect of implementing a low power and low frequency analog to digital converter (ADC) using a technique called Sigma Delta-modulation.The Sigma Delta-ADC uses few analog components but instead it requires a digital filter to extract the wanted resolution. It is this filter which is under investigation in this work.
To investigate the power consumption under the presumption that the filter would be a custom circuit implemented on-chip, a simplistic approach has been taken. Based on a high-level algorithmic investigation and the fact that it is popularly used together with Sigma Delta-modulators the Cascaded Integrator Comb (CIC) filter was chosen for implementation.
The CIC-filter uses only adders and delay elements which is a great advantage when aiming at a low power consumption. The drawback is that this filter has a poor passband which can introduce distortion within the signal band. Using the Spectre simulator provided in the Cadence Virtuoso suite the lowest power consumption achieved was 16 nW, extracting 80 % of the theoretically available resolution.
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Xiong, Zhijie. "Radio Frequency Low Noise and High Q Integrated Filters in Digital CMOS Processes." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5043.
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Radio Frequency Low Noise and High Q
Integrated Filters in Digital CMOS Processes
Zhijie Xiong
149 pages
Directed by Dr. Phillip E. Allen
Presented in this work is a novel design technique for CMOS integration of RF high Q integrated filters using positive feedback and current mode approach. Two circuits are designed in this work: a 100MHz low-noise and high Q bandpass filter suited for an FM radio front-end, and a 2.4GHz low-noise and high-Q bandpass filter suited for a Bluetooth front-end. Current-mode approach and positive feedback design techniques are successfully used in the design of both circuits. Both circuits are fabricated through a 0.18um CMOS process provided by National Semiconductor Corp.
The 100MHz circuit achieves 3.15uV RF sensitivity with 26dB SNR, and the total current consumption is 12mA. The center frequency of the filter is tunable from 80MHz to 110MHz, and the Q value is tunable from 0.5 to 28.9. 1 dB compression point is measured as -34.0dBm, combined with noise measurement results, a dynamic range of 54.1 dB results. Silicon area of the core circuit is 0.4 square millimeters.
The center frequency of the 2.4GHz circuit is tunable from 2.4GHz to 2.5GHz, and the Q value is tunable from 20 to 120. The 1 dB compression dynamic range of the circuit is 50dB. Integrated spiral inductors are developed for this design. Patterned ground shields are laid out to reduce inductor loss through substrate, especially eddy current loss when the circuit is fabricated on epi wafers. Accumulation mode MOS varactors are designed to tune the frequency response. Silicon area of the core circuit is 1 square millimeter.
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Allbutt, Geoffrey Julian. "Tuning high-frequency g[subscript]m-C filters based on short channel MOSFETs." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22265.pdf.
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Friedl, Martin. "Syntéza moderních struktur kmitočtových filtrů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-233634.
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Within modern frequency structures, the filter frequency region of up to 10 MHz constitutes a promising research topic that currently attracts intensive attention of specialists interested in the problem. The main reason of this fact consists in that the rapid development of modern technology allows the production of innovated structures of the analog frequency filters required in the defined band. In this context, however, it is also necessary to refine the methods applied in the synthesis and optimization of these structures; such improvement should be carried out with respect to fundamental properties and usability of today's active elements (operational amplifiers with voltage feedback whose Gain Bandwidth Product ranges within units of GHz, operational amplifiers with current feedback, conveyors, transimpedance operational amplifiers). In this thesis, active blocks of synthesis inductors (SIs) and frequency dependent negative resistors (FDNRs) are examined in detail, and the author provides novel formulas to define the basic parameters of the dual circuits. Due emphasis was placed on optimizing the basic building blocks of the second order and defining the variation of their properties caused by the addition of modern active elements. The blocks were analyzed and modified in view of their possible use in higher-order circuits. For active filters of a higher order, simulations were performed to indicate the actual sensitivity of the cascade and non-cascade ARC structures. The following phase of the research comprised mainly the designing of several filters, and this activity was further completed with the verification of the methodology for the synthesis and optimization of higher-order loss ladder filters with modern active blocks. Special attention was paid also to the methods enabling the optimization of such filters, which are invariably based on RLC prototypes. In order to verify the theoretical conclusions, the author materialized a large number of sample optimized filters and measured their parameters. The closing section of the thesis describes the use of the filters in specific applications.
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Ruppe, Loretta Miller. "Effects of dosing frequency on the performance of intermittently loaded packed bed wastewater filters /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Zhu, Xi. "High frequency CMOS integrated filters for computer hard disk drive and wireless communication systems." Thesis, University of Hertfordshire, 2008. http://hdl.handle.net/2299/2069.
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Operational transconductance amplifier and capacitor (OTA-C) filters have outstood among different types of filter due to high frequency and low power capabilities in the main stream digital CMOS technology. They have been widely used in computer hard disk drive (HDD) and wireless communication transceivers. OTA-C filters based on cascade and passive ladder simulation are well-known. However, multiple loop feedback (MLF) OTA-C filters which have certain advantages still have the scope for further research. So far there have been no explicit formulas for current-mode leapfrog (LF) filter design and performance evaluation of current-mode MLF OTA-C filters are still lacking. From application viewpoints, read channels for computer hard disk drives require very high frequency continuous-time filters. This automatically disqualifies active- RC/MOSFET-C filters and OTA-C filters become the only solution. In wireless communications, active-RC/MOSFET-C filters have been proved useful for mobile systems whose baseband frequency falls below a few MHz. However, for wireless LANs with the frequency of several tens of MHz, OTA-C filters are a strong candidate. Whilst in HDD read channels, cascaded OTA-C architectures have been most utilized and in wireless receivers, OTA-C structures based on ladder simulation have been popular, MLF OTA-C filters have not been practically used in either of the applications. This thesis describes some novel designs and applications of multiple loop feedback OTA-C filters with extensive CMOS simulations. Analogue filters for computer hard disk drive systems are first reviewed; the state of the art and design considerations are provided. Three VHF linear phase lowpass OTA-C filters are then designed, which include a seventh-order and a fifth-order current-mode filter based on the follow-the-leader-feedback (FLF) structure and a seventh-order voltage-mode filter using the inverse FLF (IFLF) configuration. These filters all have very low power consumption. The synthesis and design of general current-mode LF OTA-C filters are conducted next. Iterative design formulas for both all-pole and finite-zero functions are derived and explicit formulas for up to sixth-orders are given. These formulas are very easy to use for designing any type of characteristics. Subsequently, linear phase lowpass OTA-C filter design for HDD read channels using LF structures are investigated in details. A current-mode filter and a voltage-mode filter using the fifth-order LF structure are presented. The two filters can operate up to 800MHz and have very small passband phase ripple. Analogue filters for wireless communication baseband applications are also reviewed thoroughly in this thesis, where the design of a fourth-order current-mode FLF Butterworth lowpass OTA-C filter for multi-standard receivers is presented. Then two fifth-order current-mode elliptic lowpass OTA-C filters based on respective LF and FLF structures for wireless communication baseband are designed. Fifth-order voltage-mode IFLF and LF elliptic lowpass filters are also presented. All these MLF baseband filters designed can operate up to 40MHz to cover all important wireless and mobile standards. Simulations show that the LF structures have better dynamic range and stopband attenuation performances than the FLF and IFLF configurations.
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Kiani, Ghaffer I. (Ghaffer Iqbal). "Passive, active and absorbing frequency selective surfaces for wireless communication applications." Australia : Macquarie University, 2008. http://hdl.handle.net/1959.14/76611.
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"March, 2009".Thesis (PhD)--Macquarie University, Faculty of Science, Dept. of Physics & Engineering, 2008.
Bibliography: p. 145-158.
Introduction -- Frequency selective surfaces -- Absorb/transmit frequency selective surface absorber -- Switchable frequency selective surface for wireless applications -- Energy-saving glass characterisation -- Frequency selective surface solution for energy-saving glass -- Conclusion.
This thesis presents three topics related to frequency selective surfaces (FSSs), namely bsorb/transmit FSSs, active FSSs and passive bandpass FSSs for energy-saving glass used in modern buildings. These three FSSs are unique in their design and functionalities. The absorb/transmit FSS is a novel dual-layer frequency selective surface for 5 GHz WLAN applications. This FSS can stop propagation of specific bands by absorbing as opposed to re ecting, while passing other useful signals. This is in contrast to the conventional Salisbury and Jaumann absorbers, which provide good absorption in the desired band while the out-of-band frequencies are attenuated. The second topic is a single-layer bandpass active FSS that can be switched between ON and OFF states to control the transmission in 2.45 GHz WLAN applications. Previously, researchers have focused on the bandstop and dual-layer versions of the active FSS. This is in contrast to the design presented in this thesis which is single-layer and provides extra advantage in a practical WLAN environment. Also the dc biasing techniques that were used for the active FSS design are easier to implement and provide good frequency stability for different angles of incidence and polarisations in both ON and OFF states. The last topic is on the use of a bandpass FSS in energy-saving glass panels used in building design. The manufacturers of these glass panels apply a very thin metal-oxide coating on one side of the glass panels to provide extra infrared (heat) attenuation. However, due to the presence of the coating, these energy-saving glass panels also attenuate communication signals such as GSM 900, GSM 1800/1900, UMTS and 3G mobile signals etc. This creates a major communication problem when buildings are constructed with windows of this glass. In this thesis, a solution to this problem is presented by designing and etching a cross-dipole bandpass FSS on the coated side of the glass to pass the useful signals while keeping infrared attenuation at an acceptable level. One of the advantages of this FSS design is that measured material values of the metal-oxide coating are used for simulations, which have not been done previously.
Mode of access: World Wide Web.
166 p. ill. (some col.)
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Brand, Tobias Gerhardus. "Synthesis methods for multi-band coupled resonator filters." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95910.
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Thesis (PhD)--Stellenbosch University, 2014.ENGLISH ABSTRACT: In this dissertation a number of techniques to design multi-band filters, with specific focus on coupled resonator implementations, is presented. Multi-band transfer functions are constructed from single-band transfer functions using frequency mapping methods. A general class of rational mapping functions is presented that can accommodate arbitrary bandwidth specifications. Multi-band circuits are synthesised directly from multi-band transfer functions and are obtained by applying reactance transformations to single-band prototype circuits. For the direct synthesis of multi-band filters from multi-band transfer functions coupling matrix synthesis methods are employed. The circuits that result from matrix synthesis methods tend to have topologies that are undesirable from a practical perspective and must be simplified using rotations of the coupling matrix. The synthesis of multi-band filters through reactance transformations is both simple and result in filters that have practical topologies for realisation as coupled resonator circuits. Multiple filters are designed using different design methodologies and different transmission line technologies to illustrate the various design possibilities. The designs include both all-pole and cross-coupled filters and employ single-layer stripline, multi-layer stripline as well as coaxial resonators as transmission line technologies for the implementations.
AFRIKAANSE OPSOMMING: In hierdie proefskrif word verskeie ontwerpstegnieke vir multi-band filters aangebied en word daar spesifiek klem gelê op filters wat as gekoppelde resoneerder strukture geïmplimenteer kan word. Multi-band oordragsfunksies word geskep uit enkelband oordragsfunksies deur gebruik te maak van wiskundige afbeeldingstegnieke. ’n Spesiale klas van rasionale funksies word voorgestel wat spesifiek gebruik kan word om multi-band funksies te skep wat ’n arbitrêre bandwydte spesifikasie het. Multi-band stroombane word direk gesintetiseer vanuit multi-band oordragsfunksies en word ook verkry deur die toepassing van reaktansietransformasies op enkelband stroombane. Vir die direkte sintese van multi-band stroombane vanuit multi-band oordragsfunksies word stroombane gesintetiseer as koppelmatrikse. Stroombane wat op hierdie wyse gesintetiseer word is geneig om topologieë te hê wat nie baie gesog is vanuit ’n praktiese perspektief nie en matriks rotasies word dan hier ingespan om die stroombane se topologieë te vereenvoudig. Die sintese van multi-band stroombane deur gebruik te maak van reaktansietransformasies is beide eenvoudig en lei tot stroombane wat praktiese topologieë het vir implimentering as gekoppelde resoneerder strukture. Die ontwerpsmoontlikhede wat die verskillende metodieke bied word geïllustreer deur die ontwerp van verskeie filters op verskillende maniere waar daar gebruik gemaak word van verskeie transmissielyn tegnologië. Die filter ontwerpe sluit filters in waar alle transmissienulle by oneidige frekwensies is, sowel as gevalle waar somige transmissienulle by eindige frekwensies is. Die filters word geïmplimenteer deur gebruik te maak van koaksiale resoneerders sowel as enkellaag en multilaag strooklyn.
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Mohieldin, Ahmed Nader. "High performance continuous-time filters for information transfer systems." Texas A&M University, 2003. http://hdl.handle.net/1969/233.
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Singh, Sachin. "Analysis of microstrip defected ground structure filters on anisotropic substrates using HFSS /." abstract and full text PDF (free order & download UNR users only), 2005. http://0-wwwlib.umi.com.innopac.library.unr.edu/dissertations/fullcit/3209134.
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Thesis (Ph. D.)--University of Nevada, Reno, 2005."December 2005." Includes bibliographical references (leaves 213-220). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2005]. 1 microfilm reel ; 35 mm.
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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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Nilsson, Martin. "Indoor Positioning Using Opportunistic Multi-Frequency RSS With Foot-Mounted INS." Thesis, Linköpings universitet, Reglerteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-111072.
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Reliable and accurate positioning systems are expected to significantly improve the safety for first responders and enhance their operational efficiency. To be effective, a first responder positioning systemmust provide room level accuracy during extended time periods of indoor operation. This thesis presents a system which combines a zero-velocity-update (ZUPT) aided inertial navigation system (INS), using a foot-mounted inertial measurement unit (IMU), with the use of opportunistic multi-frequency received signal strength (RSS) measurements. The system does not rely on maps or pre-collected data from surveys of the radio-frequency (RF environment; instead, it builds its own database of collected rss measurements during the course of the operation. New RSS measurements are continuously compared with the stored values in the database, and when the user returns to a previously visited area this can thus be detected. This enables loop-closures to be detected online, which can be used for error drift correction. The system utilises a distributed particle simultaneous localisation and mapping (DP-SLAM) algorithm which provides a flexible 2-D navigation platform that can be extended with more sensors. The experimental results presented in this thesis indicates that the developed rss slam algorithm can, in many cases, significantly improve the positioning performance of a foot-mounted INS.