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Lane, Roger Benton 1951. "Alternate passive low pass filter realizations." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/291743.
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The objective of this thesis investigation is to find by computer optimization methods alternate passive realizations for the double resistance terminated low pass Butterworth filters for the third through the tenth order. A second goal is to explain why they exist and to explore other means to derive them. The iterative optimization search performed uses the GOSPEL computer program. New realizations found by this method are presented. Aspects of error and accuracy are discussed as well as a figure of merit test which confirms the validity of the results. Alternate filter realizations produced by selection of left-half-plane zeros for the power reflection coefficient are discussed and a detailed example using this process is performed.
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Talej, Elie N. "A VLSI design of a finite impulse response low-pass digital filter." Ohio : Ohio University, 1988. http://www.ohiolink.edu/etd/view.cgi?ohiou1182871591.
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Li, Heli. "RF LOW PASS FILTER DESIGN AND FABRICATION USING INTEGRATED PASSIVE DEVICE TECHNOLOGY." Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4340.
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In this thesis, the whole process of design a low pass filter (LPF) for the wireless communication application has been presented. Integrated passive device technology based on GaAs substrate has been utilized to make the LPF. Schematic simulation and electromagnetic simulations are extensively used in the design process. EM simulation is used in the selection of layout design and processing parameters for design optimization of both the inductors and IPD harmonic filters. The effective use of EM simulation enables us to realize the successful development of high performance harmonic filters. To make the optimization be more flexible and also for a deeper understanding of the optimization theory, optimization using genetic algorithm is also implemented. The weight of each targets are adjustable, and a non-uniformly distributed goal for the harmonic rejection range is introduced to achieve better optimization results. The embedded LPF is built and measurement results show good agreement with the simulation data. This kind of very compact, high performance harmonic filters can be used in radio transceiver front-end modules. The realized harmonic filters have insertion loss less than 0.6 dB and harmonic rejections greater than 25 dB with a compact die size of 0.8 mm2.M.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering
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Csipkes, Gabor-Laszlo. "Integrated realizations of reconfigurable low pass and band pass filters for wide band multi-mode receivers." Doctoral thesis, [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=979677483.
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Csipkes, Gabor-Laszlo. "Integrated realizations of reconfigurable low pass and band pass filters for wide band multi-mode receivers." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2006. http://nbn-resolving.de/urn:nbn:de:swb:14-1145345696511-52655.
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With the explosive development of wireless communication systems the specifications of the supporting hardware platforms have become more and more demanding. According to the long term goals of the industry, future communications systems should integrate a wide variety of standards. This leads to the idea of software defined radio, implemented on fully reconfigurable hardware.Among other reconfigurable hardware blocks, suitable for the software radio concept, an outstanding importance belongs to the reconfigurable filters that are responsible for the selectivity of the system. The problematic of filtering is strictly connected to the architecture chosen for a multi-mode receiver realization. According to the chosen architecture, the filters can exhibit low pass or band pass frequency responses.The idea of reconfigurable frequency parameters has been introduced since the beginning of modern filtering applications due to the required precision of the frequency response. However, the reconfiguration of the parameters was usually done in a limited range around ideal values. The purpose of the presented research is to transform the classical filter structures with simple self-correction into fully reconfigurable filters over a wide range of frequencies. The ideal variation of the frequency parameters is continuous and consequently difficult to implement in real circuits. Therefore, it is usually sufficient to use a discrete programming template with reasonably small steps.There are several methods to implement variable frequency parameters. The most often used programming templates employ resistor and capacitor arrays, switched according to a given code. The low pass filter implementation proposed in this work uses a special switching template, optimized for a quasi-linear frequency variation over logarithmic axes. The template also includes the possibility to compensate errors caused by component tolerances and temperature. Another important topic concerns the implementation of programmable band pass filters, suitable for IF sampling receivers. The discussion is centered on the feasibility and the flexibility of different band pass filter architectures. Due to the high frequency requirements, the emphasis lays on filters that employ transconductance amplifiers and capacitorsDie rasch fortschreitende Entwicklung drahtloser Kommunikationssysteme führt zu immer anspruchsvolleren Spezifikationen der diese Systeme unterstützenden Hardwareplattformen. Zukünftige Kommunikationssysteme sollen übereinstimmend mit den längerfristigen Zielen der Industrie verschiedene Standards integrieren. Dies führt zu der Idee von vollständig rekonfigurierbarer Hardware, welche mittels Software gesteuert wird.Inmitten anderer rekonfigurierbarer Hardwareblöcke, die für das Software Radio Konzept geeignet sind, besitzen die steuerbaren Filter, welche wesentlichen Einfluss auf die Selektivität des Systems haben, eine enorme Bedeutung. Die Filterproblematik ist eng mit der gewählten Architektur der standardübergreifenden Empfängerrealisierung verknüpft. Die Filter können entsprechend der ausgesuchten Architektur Tiefpass- oder Bandpasscharakter annehmen.Die Idee rekonfigurierbarer Frequenzparameter wurde bereits mit Beginn moderner Filteranwendungen auf Grund geforderter Frequenzganggenauigkeit umgesetzt. Jedoch wurde die Parameterrekonfiguration üblicherweise nur in einem begrenzten Bereich um die Idealwerte herum vorgenommen. Das Ziel der vorgestellten Forschungsarbeit ist es, diese klassischen Filterstrukturen mit einfacher Selbstkorrektur in über große Frequenzbereiche voll rekonfigurierbare Filter zu transformieren. Idealerweise werden die Frequenzparameter kontinuierlich variiert weswegen sich die Implementierung in reellen Schaltkreisen als schwierig erweist. Deshalb ist es üblicherweise ausreichend, ein diskretes Steuerschema mit kleinen Schrittweiten zu verwenden.Es gibt verschiedene Methoden, variable Frequenzparameter zu implementieren. Die meisten Schemata verwenden Widerstands- und Kondensatorfelder, die entsprechend eines Kodes geschaltet werden. Die in dieser Arbeit vorgestellte Implementierung eines Tiefpassfilters nutzt ein spezielles Umschaltschema, welches für die quasi-lineare Frequenzvariation bei Darstellung über logarithmischen Axen optimiert wurde. Es beinhaltet weiterhin die Möglichkeit, Fehler zu kompensieren, die durch Bauelementtoleranzen und Temperaturschwankungen hervorgerufen werden.Ein weiteres interessantes Thema betrifft die Implementierung steuerbarer Bandpassfilter, die für Empfänger mit Zwischenfrequenzabtastung geeignet sind. Die Betrachtung beschränkt sich hierbei auf die Durchführbarkeit und Flexibilität verschiedener Bandpassfilterarchitekturen. Auf Grund hoher Frequenzanforderungen liegt der Schwerpunkt auf Filtern, die auf Transkonduktanzverstärkern und Kondensatoren basieren
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Sánchez, Ripoll Juan Pedro. "Design of a sharp response low-pass filter : through comparison of microwave design software." Thesis, Högskolan i Gävle, Avdelningen för elektronik, matematik och naturvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-12365.
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The aim of this thesis is to do a research about three microwave design software packages and evaluate them with the purpose of getting the sharpest filter as possible and also know which one is more efficient in this task. In order to achieve this purpose we designed, simulated and tried to manufacture the same low-pass filter (using microstrip lines) in different software. This way we are able to compare features as the S-parameters of the filters, the possibilities they give us, how easy to use they are, how long takes us to run a simulation, how much deviation they have in the simulations and how much deviation we get in the measurements of the manufactured filters. The filter has to be a low-pass filter with the cut off frequency at 1.8 GHz and a minimum attenuation of -26dB at 4.6 GHz. The next step will be design of the 3 filters with the 3 different software. Once we have done the designs we are ready to do simulations and manufacture them in order to evaluate which one of them is more accurate and give us the best response. To do the measurements we used a Vector Network Analyzer, in order to get the S-parameters, and a Vector Signal Generator and a Signal Analyzer in order to check the response of the filters with real signals. Finally, as a conclusion, evaluating all the results we got we can say that ADS is the software package that has more positive points and therefore the best suited to our needs.
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Kumar, Bhunesh. "Design of Harmonic Filters for Renewable Energy Applications." Thesis, Högskolan på Gotland, Institutionen för kultur, energi och miljö, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hgo:diva-1862.
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Harmonics are created by non-linear devices connected to the power system. Power system harmonics are multiples of the fundamental power system frequency and these harmonic frequencies can create distorted voltages and currents. Distortion of voltages and currents can affect the power system adversely causing power quality problems. Therefore, estimation of harmonics is of high importance for efficiency of the power system network. The problem of harmonic loss evaluation is of growing importance for renewable power system industry by impacting the operating costs and the useful life of the system components. Non-linear devices such as power electronics converters can inject harmonics alternating currents (AC) in the electrical power system. The number of sensitive loads that require ideal sinusoidal supply voltage for their proper operation has been increasing. To maintain the quality limits proposed by standards to protect the sensitive loads, it is necessary to include some form of filtering device to the power system. Harmonics also increases overall reactive power demanded by equivalent load. Filters have been devised to achieve an optimal control strategy for harmonic alleviation problems. To achieve an acceptable distortion, increase the power quality and to reduce the harmonics hence several three phase filter banks are used and connected in parallel. In this thesis, high order harmonics cases have been suppressed by employing variants of Butterworth, Chebyshev and Cauer filters. MATLAB/SIMULINK wind farm model was used to generate and analyze the different harmonics magnitude and frequency. High voltage direct current (HVDC) lines for an electrical grid that is more than50km far away wind farm generation plant was investigated for harmonics. These HVDC lines are also used in offshore wind farm plant. Investigated three-phase harmonics filters are shunt elements that are used in power systems for decreasing voltage distortion and for correcting the power factor. Renewable energy sources are not the stable source of energy generation like wind, solar and tidal e.t.c. Though they are secondary sources of generation and hard to connect with electrical grid. In near future the technique is to use the wave digital filter (WDF) or circulator-tree wave digital filter (CTWDF) for the renewable energy application can be employed to mitigate the harmonics. These WDF and CTWDF can b eused in HVDC lines and smart grid applications. A preliminary analysis is conducted for such a study.
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Chabbi, Charef. "VLSI NMOS hardware design of a linear phase FIR low pass digital filter." Ohio University / OhioLINK, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1183749814.
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Law, Yiu Kui. "Design and Testing of Off-The-Shelf Electronic Components for an Acoustic Emission Structural Health Monitoring System Using Piezoelectric Sensors." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34477.
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The safety concern of aging aircraft is a rising issue in terms of both safety and cost. An aircraft structure failure during flight is unacceptable. A method needs to be developed and standardized to test the integrity of both commercial and military aircrafts. The current method to test the structure of an aircraft requires the aircraft to be taken out of service for inspection; this is costly due to the inspection required to be performed and the lost use from downtime.
A novice idea of an on-site structural health monitoring (SHM) system has been proposed to test the integrity of aircraft structure. An on-site system is a system that can be used to perform inspection on an aircraft simultaneously while the aircraft is in use. This SHM system uses the principles of active lamb wave and passive acoustic emission through the use of piezoelectric sensors as the sensing elements. Piezoelectric sensors can be used both as an input device and as a sensing element.
This research focuses on the development of the major data acquisition electronic components of the system. These components are charge amplifier, high pass filter, low pass filter and line driver. A charge amplifier converts a high impedance signal to a low impedance signal. A high pass filter attenuates the low frequency content of a signal, while a low pass filter attenuates the high frequency content of a signal. A line driver converts a low current signal to a high current signal. All of these components need to operate up to a frequency of 2 MHz. Off-the-shelf electronics will be used for prototyping as custom components will not be feasible at this point of the research.Master of Science
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Abbasi, Muneeb Mehmood, and Mohammad Abdul Jabbar. "Design and Performance Analysis of Low-Noise Amplifier with Band-Pass Filter for 2.4-2.5 GHz." Thesis, Linköpings universitet, Fysik och elektroteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-91326.
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Low power wireless electronics is becoming more popular due to durability, portability and small dimension. Especially, electronic devices in instruments, scientific and medical (ISM) band is convenient from the spectrum regulations and technology availability point of view. In the communication engineering society, to make a robust transceiver is always a matter of challenges for the better performance. However, in this thesis work, a new approach of design and performance analysis of Low-Noise Amplifier with Band-Pass filter is performed at 2.45 GHz under the communication electronics research group of Institute of Science and Technology (ITN). Band-Pass Filtered Low-Noise Amplifier is designed with lumped components and transmission lines. Performances of different designs are compared with respect to noise figure, gain, input and output reflection coefficient. In the design process, a single stage LNA is designed with amplifier, ATF-58143. Maximally flat band-pass (BPF) filters were designed with lumped components and distributed elements. Afterwards, BPF is integrated with the LNA at the front side of LNA to get a compact Band-Pass Filtered Low-Noise Amplifier with good performance. Advanced Design System (ADS) tool was used for design and simulation, and each design was tuned to get the optimum value for noise figure, gain and input reflection coefficient. LNA stand-alone gives acceptable value of noise figure and gain but the bandwidth was too wide compared to specification. Band-Pass Filtered Low-Noise Amplifier with lumped components gives also considerable values of noise and gain. But the gain was not so flat and the bandwidth was also wide. Then, Band-Pass Filtered Low-Noise Amplifier was designed with transmission lines where the optimum value of noise figure and gain was found. The gain was almost flat over the whole band, i.e., 2.4-2.5 GHz compared to LNA stand-alone and Band-Pass Filtered Low-Noise Amplifier designed with lumped components. It is observed that deviations of results from schematic to layout level are considerable, i.e., electromagnetic simulation is needed to predict the Band-Pass Filtered Low-Noise Amplifier performance. Prototype of LNA, Band-Pass Filtered Low-Noise Amplifier with lumped and transmission lines are made at ITN’s PCB laboratory. Due to unavailability of exact values of Murata components and for some other technical reasons, the measured values of Band-Pass Filtered Low-Noise Amplifier with lumped components and transmission lines are deviated compared to predicted values from simulation.
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Leu, Ching-Shan. "Improved Forward Topologies for DC-DC applications with Built-in Input Filter." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/26073.
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Among PWM power conversion topologies, the single-switch forward topology is the one that has been most widely used for decades. Its popularity has been based on many factors, including its low cost, circuit simplicity and high efficiency.
However, several issues need to be addressed when using the forward converter such as the core reset, the voltage spikes caused by the transformer leakage inductance, and the pulsating input current waveform.
The transformer is driven in a unidirectional fashion in the forward converter; a tertiary forward converter (TFC) is an example of this. Therefore, the third winding and reset diode must be provided with an adequate period of reset time so that the flux can be fully reset by the end of each switching cycle to prevent core saturation.
Also, due to the utilization of a transformer, leakage inductances cannot be avoided. The energy stored in the leakage inductance during current ramp-up is not transferred to the load, and is not recovered during its discharge phase. As a result, the VDS waveform has a voltage spike and undesirable high-frequency oscillation. Therefore, a higher voltage-rating switch should be used to reduce the risk of high-voltage breakdown. Although a switch with amply high voltage ratings is available, it would tend to have a higher on-resistance, RDS(ON), resulting in increased conduction losses. Moreover, selection of a switch with higher voltage ratings than necessary may needlessly increase the cost of the design.
Usually an additional circuit such as a snubber circuit or a clamp circuit or the soft-switching technique is used to absorb these voltage spikes. Consequently, the leakage inductance is intentionally minimized in the PWM power conversion technique so that it will not degrade the circuit performance. In contrast, the leakage inductance of the transformer may enhance rather than detract from circuit performance with a resonant power conversion technique.
To date, however, no single-switch forward converter has been claimed to be able to enhance the converter performance with the PWM power conversion technique by utilizing the leakage inductance. Therefore, research on the utilization of the transformer leakage inductance in the PWM forward converter is needed. Two techniques, input current ripple reduction and an embedded filter, are proposed to enhance the performance of forward converter using the PWM technique.
By inserting a capacitor between two primary windings of the TFC, an input current ripple reduction technique is proposed and a forward converter with ripple reduction (FRR) is presented in this research work. Because the voltage of the capacitor is clamped to input voltage, the capacitor becomes a second voltage source to share part of the load current. As a result, the input current ripple is reduced. Moreover, the capacitor voltage is clamped both at the static and dynamic states; thus the excessive voltage stress on the main switch S1 of the FAC during low-line to high-line step transient is eliminated.
Furthermore, without an external LC filter, the EMI noise levels can be further reduced as a result of the embedded notch filter formed by the transformer leakage inductance and clamp capacitor if the notch frequency is designed to be the same as the switching frequency. With the help of the clamp capacitor, therefore, the leakage inductance can enhance rather than detract from the converter performance.
The input current ripple can be reduced further by employing the proposed techniques. Two sets of the clamp capacitors and the leakage inductances are utilized, and the current ripple can even be cancelled if the condition is met. Consequently, the input current becomes a non-pulsating waveform and a forward converter with ripple cancellation (FRC) is presented. Moreover, without an external LC filter, the EMI noise levels can be further attenuated as a result of the embedded low-pass filter formed by the transformer leakage inductances and clamp capacitors. Again, the leakage inductance can enhance the converter performance just as the resonant converter does.
In addition to providing the analysis and design procedure, this work verifies the performance of the presented converters, the FRR and the FRC, by the experimental results.
By employing the proposed techniques, eight new topologies have been extended for different power conversion applications. Each member of the FRR and the FRC families is able to enhance the converter performance, in ways such as the elimination of the voltage spikes on the main switch without a snubber circuit and the improvement of the EMI performance with small filter components. Consequently, the cost can be reduced and the space of the converter can be saved.Ph. D.
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Jeleček, Jiří. "Pseudo-diferenční kmitočtové filtry vyššího řádu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-401954.
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This Master's thesis deals with pseudo-differential frequency higher order filters working in voltage mode. The thesis deals with the description of frequency filters, their types and applications. Follows an analysis of differential and pseudo-differential transmissions. Next part contains a description of used active elements (conveyors) at thesis (CCII, DVCC, DDCC, UCC). In the last part the thesis is devoted to the own design of the pseudo-differential filter. Design functionality is verified by experimental simulation.
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Kufa, Martin. "Numerická syntéza filtrujících antén." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-233677.
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Dizertační práce je zaměřena na kompletní metodiku návrhu tří a čtyř prvkových flíčkových anténních řad, které neobsahují žádné filtrující části a přesto se chovají jako filtrující antény (filtény). Návrhová metodika kombinuje přístup pro návrh filtrů s přístupem pro anténní řady a zahrnuje tvarování frekvenčních odezev činitele odrazu a normovaného realizovaného zisku. Směr hlavního laloku přes pracovní pásmo je kontrolován také. S cílem kontrolovat tvary uvedených charakteristik, nové gi koeficienty jsou představeny pro návrh filtrujících anténních řad. Návrhová metodika byla ověřena na tří a čtyř prvkové filtrující anténní řadě přes frekvenční pásmo od 4,8 GHz do 6,8 GHz, pro šířku pásma celé struktury od 7 % do 14 % a pro požadovanou úroveň činitele odrazu od –10 dB do –20 dB. Celá metodika byla podpořena výrobou a měřením šesti testovacích vzorků filtrujících anténních řad s rozdílnými konfiguracemi. Ve všech případech se simulované a naměřené výsledky dobře shodují.
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Jonasson, Anders. "Konstruktion och utvärdering av Current Conveyors." Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1976.
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Normally the operational amplifier is used as a component in active filter design. The goal for future components in filter design is large bandwith and the use of low supply voltages. The use of current-mode instead of voltage-mode circuits gets a step closer to the required performance. A component that use current as the signal conveying part is the current conveyor. In this report a comparative study between two current conveyor structures of second generation (CCII) is performed. The most suited is later implemented and simulated using the CMOS process AMS.C035. The component is also tested in a continuous-time elliptic low-pass filter of leapfrog type. The filter does not behave as it should. However, better performance can be obtained by redesigning the current conveyor.
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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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Sládok, Ondřej. "Diferenční a pseudodiferenční kmitočtové filtry." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241951.
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This thesis deals with fully differential and pseudo-differential frequency filters. Significant emphasis is placed on the characteristics of common-mode signal. Further, the text deals with the design issue of fully-differential structure and transformation of non-differential to pseudo-differential structures. In the thesis one non-differential structure, one fully-differential and three pseudo-differential structures are proposed, one of them working in current mode. The thesis also describes the analysis from the perspective of non-ideal properties of the active element of two circuit solutions, which is trying to find the optimal solution. In each case, functionality of new solutions is verified by simulations and in several cases also by experimental measurement.
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Pavlikovský, Vladislav. "Využití reverberátorů pro úpravu akustiky prostoru." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220198.
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This diploma thesis deals with adjusting the reverberation time of enclosed spaces. It is divided into two thematic areas. The first thematic area deals with active systems that adjust the reverberation time, with a stronger focus on usage of reverberators to simulate secondary spaces. The second thematic area is the implementation of reverberators and their fundamental building blocks in Matlab.
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Třeček, Stanislav. "Aktivní elektrické filtry na bázi obvodů se spínanými kapacitory." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217796.
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This thesis deals with concept of universal frequency filter by application of a switched-capacitor functional block. The concept is based on the theory of switched-capacitor circuits and the theory of a design of classical frequency filters. The printed circuit board was designed based on the filter connection developed by using a software Eagle. The filter was implemented as a laboratory product. This product has been revitalized and the frequency response of all types of filters has been measured. The measured parameters were compared with the parameters set out in the technical documentation of functional block.
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Bragina, Tatiana. "Návrh laditelného kmitočtového filtru 2. řádu se spínanými kapacitory." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-221041.
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Thesis describes analog filters topologies with capability of tuning of the main parameters and the MOSFET-C and switched-capacitor filters are described. With focus to linearity and maximal tuning range optimal topology have been chosen. In work the issue of analog switch design is described and is solved. Design of switched-capacitor low-pass Sallen-key filter in Cadence software was made and simulation results are presented.
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Štěpánek, Michal. "Návrh diplexeru na bázi koaxiálních rezonátorů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-219960.
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This thesis deals with the analysis of coaxial cavity filters and synthesis of generic topology of these filters. Transfer function comes out the synthesis, which is based on low-pass prototype and similarity with real structure. The next aim of this thesis is to build the basic software for coaxial cavity filters synthesis from engaged characteristic parameters of the filter. This work also includes the analysis of coupling matrix synthesis based on transfer function, where we can use direct coupling or cross-coupling between resonators. The last point is focused on the diplexer filter based on specified parameters and obtained coupling matrix. Entire diplexer model is optimized using Tuning-Space Mapping method.
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Long, Zeyu. "Introduction of the Debye media to the filtered finite-difference time-domain method with complex-frequency-shifted perfectly matched layer absorbing boundary conditions." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/introduction-of-the-debye-media-to-the-filtered-finitedifference-timedomain-method-with-complexfrequencyshifted-perfectly-matched-layer-absorbing-boundary-conditions(441271dc-d4ea-4664-82e6-90bf93f5c2b7).html.
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The finite-difference time-domain (FDTD) method is one of most widely used computational electromagnetics (CEM) methods to solve the Maxwell's equations for modern engineering problems. In biomedical applications, like the microwave imaging for early disease detection and treatment, the human tissues are considered as lossy and dispersive materials. The most popular model to describe the material properties of human body is the Debye model. In order to simulate the computational domain as an open region for biomedical applications, the complex-frequency-shifted perfectly matched layers (CFS-PML) are applied to absorb the outgoing waves. The CFS-PML is highly efficient at absorbing the evanescent or very low frequency waves. This thesis investigates the stability of the CFS-PML and presents some conditions to determine the parameters for the one dimensional and two dimensional CFS-PML.The advantages of the FDTD method are the simplicity of implementation and the capability for various applications. However the Courant-Friedrichs-Lewy (CFL) condition limits the temporal size for stable FDTD computations. Due to the CFL condition, the computational efficiency of the FDTD method is constrained by the fine spatial-temporal sampling, especially in the simulations with the electrically small objects or dispersive materials. Instead of modifying the explicit time updating equations and the leapfrog integration of the conventional FDTD method, the spatial filtered FDTD method extends the CFL limit by filtering out the unstable components in the spatial frequency domain. This thesis implements filtered FDTD method with CFS-PML and one-pole Debye medium, then introduces a guidance to optimize the spatial filter for improving the computational speed with desired accuracy.
22
Best, Eric A. "Stability assessment of nonlinear systems using the lyapunov exponent." Ohio University / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1175019061.
Full text
23
Johansson, Viktor. "A sensor orientation and signal preprocessing study of a personal fall detection algorithm." Thesis, Högskolan Kristianstad, Fakulteten för naturvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-21375.
Full textAbstract:
This study investigates if a smartphones orientation in the pocket affects the result of a decision tree model trained with data from personal falls, and also how a low-pass filter affects these results. A comparison is made between the results gathered from this study, compared to previous studies and products within the field. The data was gathered using a smartphone application and was later split up to get datasets for all the different orientations of the smartphone. Before training the models, the data was processed through a low pass filter. Results showed that low pass filtered signals generally performed better and that two of the trained models, could outscore at least one other algorithm cited in this thesis in at least one category. However, existing products on the market that were investigated do not disclose their statistics and a comparison to these products could not be made. The best two orientations for the phone to be placed in the pocket was when the face of the phone was pointing out from the leg, and top of the phone was pointing up and also when the face of the phone was pointing out from the leg, and the top of the phone was pointing down.
24
Fröhlich, Lubomír. "Aktivní kmitočtové filtry pro vyšší frekvence." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-233616.
Full textAbstract:
This thesis deals with the synthesis and optimization of frequency analogue filters with modern active elements usable for higher frequencies. The thesis is divided into three parts, the first part deals with the problematic concerning Leap-Frog combined ARC structure. Due to a difficult design, this method is not described in a detail and used in practice, although it shows e.g. low sensitivity. Firstly, a complete analysis of individual filters was made (for and T endings) and consequently these findings were used during implementation of this method to NAF program. Finally, samples of real filters were realized (for verification of functioning and correct design). Another very interesting topic concerning filters is usage of coupled band-pass for small bandwidth, where it is necessary to solve the problems concerning ratio of building elements values, but also price, quality, size of coils, sensitivity, Q factors, coefficients etc. That is why in practice a coil is very often substituted with other equivalent lossy and lossless blocks which create ARC filters structure. The design and the possibility of usage of lossy grounded elements were described here (such as synthetic inductors, frequency dependent negative resistor). Some parts of the design are individual computer sensitivity analysis, setting of usage and quality comparison of individual lossy grounded blocks. Besides, a program for these elements was created, it is useful for a quick design and depiction of transfer characteristics. The third part deals with the usage of tuning universal filters consisting three or more operational amplifiers, which secures its universality and possibility to create different kinds of transfer characteristic. In practice, Akerberg - Mossberg and Kerwin - Huelsman - Newcomb are the most used types of filters. These were also compared with less common universal filters. In the end, the possibility of digital tuning of universal filter with the help of digital potentiometers for filters of 10th order and frequency around 1 MHz was shown.
25
Dvořák, Jan. "Řiditelné analogové elektronické obvody neceločíselného řádu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-433474.
Full textAbstract:
Disertační práce se zabývá syntézou a analýzou nových obvodových struktur neceločíselného (fraktálního) řádu s řiditelnými parametry. Hlavní cíl této práce je návrh nových řešení filtračních struktur fraktálního řádu v proudovém módu, emulátorů prvků fraktálního řádu a také oscilátorů. Práce obsahuje návrh tří emulátorů pasivního prvku fraktálního řádu, tři filtrační struktury a dva oscilátory navržené na základě využití pasivního prvku fraktálního řádu v jejich obvodové struktuře a dvě obecné koncepce filtrů fraktálního řádu založené na využití aproximace přenosové funkce fraktálního řádu. Na základě obecných koncepcí jsou v práci navrženy filtry fraktálního řádu typu dolní a horní propust. Díky aktivním prvkům s přeladitelnými parametry, které jsou užity v obvodových strukturách je zajištěna řiditelnost řádu filtru, jeho pólového kmitočtu a některých případech i činitele jakosti. Vlastnosti všech zapojení jsou ověřeny počítačovými simulacemi za pomoci behavioralních simulačních modelů aktivních prvků. Některé z uvedených obvodů byly realizovány na DPS a jejich vlastnosti ověřeny experimentálním měřením.
26
Ould, Amer Khadidja. "Prétraitements des images sous-marines basés sur la polarisation et le filtrage fréquentiel : application offshore Enhancing underwater optical imaging by using a low-pass polarization filter, in Optics Express 27(2), 2019." Thesis, Brest, 2019. http://www.theses.fr/2019BRES0049.
Full textAbstract:
L'étude du milieu sous-marin nécessite des avancées technologiques importantes notamment en ce qui concerne le développement des véhicules sous-marins autonomes et en particulier, leurs capteurs de perception. Le travail de cette thèse avait pour objectif d'apporter des solutions permettant d'améliorer la qualité des images sous-marines dans le but de promouvoir l'emploi des robots sous-marins autonomes. La rapidité de calcul est un point très essentiel, car les robots autonomes sont limités par les contraintes d'énergie, la capacité de calcul et de stockage. Dans ce contexte, une méthode rapide et efficace d'amélioration de la qualité d’images sous-marines a été proposée. D'une part, cette méthode utilise un système optique d'imagerie polarimétrique pour réduire les effets de diffusion lors de l'acquisition d'images. D'autre part, elle est basée sur une version optimisée de la méthode DCP (dark channel prior) qui est très répondue pour le débrumage d’images sous-marines.Dans cette thèse, nous nous intéressons également à la détection et à l'identification de marqueurs utilisés pour le docking automatique d'un véhicule sous-marin avec une station immergée. Le succès de cette tâche nécessite un bon contraste dans la zone où se situe le marqueur. Pour résoudre ce problème, une méthode de débrumage orientée-objet est proposée pour optimiser le contraste des marqueurs. La stratégie proposée exploite les caractéristiques de texture dérivées du filtrage multicanal de Gabor pour la segmentation d'images. Une fois que les différents objets de l’image sont séparés, une version optimisée du Dark Channel Prior (DCP) est appliquée pour optimiser le contraste de chaque objet. Les résultats obtenus, sur une large base de données d’images de marqueurs, montrent que la méthode proposée améliore sensiblement la détection et l'identification des marqueurs en environnement sous-marinStudy of the underwater environment requires significant technological advances, particularly, in the development of autonomous underwater vehicles, and their perception sensors. This thesis is dealing with the development of a real time solution for underwater image quality improvement in order to promote the use of autonomous underwater vehicles. Developing a fast image processing algorithms are required due the limitations of these kinds of vehicles in terms of energy, computing capacity and storage. In this context, a fast and effective method of underwater image quality improvement has been proposed. On the one hand, this method uses a polarimetric imaging optical system to reduce the diffusion effects on the image acquisition.On the other hand, it is based on an optimized version of the dark channel prior (DCP) method that has received a great deal for image dehazing.In this thesis, we are also interested in the detection and the identification of markers used for the automatic docking of an underwater vehicle with a submerged station. The success of this task requires a good contrast in the area where the marker is located. To solve this problem, an object-oriented dehazing method is proposed to optimize the contrast of markers. The proposed strategy exploits the texture features derived by Gabor multichannel filtering for image segmentation. Once different objects of the image are separated, an optimized Dark Channel Prior dehazing method is applied to optimize the contrast of each individual object. The system has been tested on a large image dataset and the obtained results show that the object-oriented dehazing improves the markers identification in underwater environment
27
Camlica, Fahri Bugra. "Demonstration Of A Stabilized Hovering Platform For Undergraduate Laboratory." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12605772/index.pdf.
Full textAbstract:
This research work covers the design, manufacture and testing of an unmanned aerial vehicle for the purpose of testing various control systems by undergraduate students in the laboratory environment. The aerial vehicle under
consideration is a four-rotor propeller powered. Aluminum rod based mechanical structure is preferred. The stabilization of the hovering vehicle in its rotational axes in the air and navigation about the yaw axis are the accomplished goals of this study. The aerial vehicle is run in real time by using Matlab 6.5 Software&rsquos xPc module. The linear quadratic regulator and PD controllers are utilized to stabilize the aerial vehicle in its rotation axes. To eliminate the measurement noise generated by the sensors, low-pass second order transfer function is designed and its implementation to real time experiments is discussed.
28
Nagarajan, N. "Autonomous Orbit Estimation For Near Earth Satellites Using Horizon Scanners." Thesis, Indian Institute of Science, 1994. https://etd.iisc.ac.in/handle/2005/155.
Full textAbstract:
Autonomous navigation is the determination of satellites position and velocity vectors onboard the satellite, using the measurements available onboard. The orbital information of a satellite needs to be obtained to support different house keeping operations such as routine tracking for health monitoring, payload data processing and annotation, orbit manoeuver planning, and prediction of intrusion in various sensors' field of view by celestial bodies like Sun, Moon etc. Determination of the satellites orbital parameters is done in a number of ways using a variety of measurements. These measurements may originate from ground based systems as range and range rate measurements, or from another satellite as in the case of GPS (Global Positioning System) and TDUSS (Tracking Data Relay Satellite Systems), or from the same satellite by using sensors like horizon sensor^ sun sensor, star tracker, landmark tracker etc. Depending upon the measurement errors, sampling rates, and adequacy of the estimation scheme, the navigation accuracy can be anywhere in the range of 10m - 10 kms in absolute location.
A wide variety of tracking sensors have been proposed in the literature for autonomous navigation. They are broadly classified as (1) Satellite-satellite tracking, (2) Ground- satellite tracking, (3) fully autonomous tracking. Of the various navigation sensors, it may be cost effective to use existing onboard sensors which are well proven in space. Hence, in the current thesis, the Horizon scanner is employed as the primary navigation sensor-. It has been shown in the literature that by using horizon sensors and gyros, a high accuracy pointing of the order of .01 - .03 deg can be achieved in the case of low earth orbits. Motivated by such a fact, the current thesis deals with autonomous orbit determination using measurements from the horizon sensors with the assumption that the attitude is known to the above quoted accuracies.
The horizon scanners are mounted on either side of the yaw axis in the pitch yaw plane at an angle of 70 deg with respect to the yaw axis. The Field Of View (FOV) moves about the scanner axis on a cone of 45 deg half cone angle. During each scan, the FOV generates two horizon points, one at the space-Earth entry and the other at the Earth-space exit. The horizon points, therefore, lie• on the edge of the Earth disc seen by the satellite. For a spherical earth, a minimum of three such horizon points are needed to estimate the angular radius and the center of the circular horizon disc. Since a total of four horizon points are available from a pair of scanners, they can be used to extract the satellite-earth distance and direction.These horizon points are corrupted by noise due to uncertainties in the Earth's radiation pattern, detector mechanism, the truncation and roundoff errors due to digitisation of the measurements. Owing to the finite spin rate of the scanning mechanism, the measurements are available at discrete time intervals. Thus a filtering algorithm with appropriate state dynamics becomes essential to handle the •noise in the measurements, to obtain the best estimate and to propagate the state between the measurements. The orbit of a low earth satellite can be represented by either a state vector (position and velocity vectors in inertial frame) or Keplerian elements. The choice depends upon the available processors, functions and the end use of the estimated orbit information. It is shown in the thesis that position and velocity vectors in inertial frame or the position vector in local reference frame, do result in a simplified, state representation. By using the f and g series method for inertial position and velocity, the state propagation is achieved in linear form.
i.e. Xk+1 = AXK
where X is the state (position, velocity) and A the state transition matrix derived from 'f' and 'g' series. The configuration of a 3 axis stabilised spacecraft with two horizon scanners is used to simulate the measurements.
As a step towards establishing the feasibility of extracting the orbital parameters, the governing equations are formulated to compute the satellite-earth vector from the four horizon points generated by a pair of Horizon Scanners in the presence of measurement noise. Using these derived satellite-earth vectors as measurements, Kalman filter equations are developed, where both the state and measurements equations are linear. Based on simulations, it is shown that a position accuracy of about 2 kms can be achieved. Additionally, the effect of sudden disturbances like substantial slewing of the solar panels prior and after the payload operations are also analysed. It is shown that a relatively simple Low Pass Filter (LPF) in the measurements loop with a cut-off frequency of 10 Wo (Wo = orbital frequency) effectively suppresses the high frequency effects from sudden disturbances which otherwise camouflage the navigational information content of the signal. Then Kalman filter can continue to estimate the orbit with the same kind of accuracy as before without recourse to re-tuning of covariance matrices.
Having established the feasibility of extracting the orbit information, the next step is to treat the measurements in its original form, namely, the non-linear form. The entry or exit timing pulses generated by the scanner when multiplied by the scan rate yield entry or exit azimuth angles in the scanner frame of reference, which in turn represents an effective measurement variable. These azimuth angles are obtained as inverse trigonometric functions of the satellite-earth vector. Thus the horizon scanner measurements are non-linear functions of the orbital state. The analytical equations for the horizon points as seen in the body frame are derived, first for a spherical earth case. To account for the oblate shape of the earth, a simple one step correction algorithm is developed to calculate the horizon points. The horizon points calculated from this simple algorithm matches well with the ones from accurate model within a bound of 5%. Since the horizon points (measurements) are non-linear functions of the state, an Extended Kalman Filter (EKF) is employed for state estimation. Through various simulation runs, it is observed that the along track state has got poor observability when the four horizon points are treated as measurements in their original form, as against the derived satellite-earth vector in the earlier strategy. This is also substantiated by means of condition number of the observability matrix. In order to examine this problem in detail, the observability of the three modes such as along-track, radial, and cross-track components (i.e. the local orbit frame of reference) are analysed. This difficulty in observability is obviated when an additional sensor is used in the roll-yaw plane. Subsequently the simulation studies are carried out with two scanners in pitch-yaw plane and one scanner in the roll-yaw plane (ie. a total of 6 horizon points at each time). Based on the simulations, it is shown that the achievable accuracy in absolute position is about 2 kms.- Since the scanner in the roll-yaw plane is susceptible to dazzling by Sun, the effect of data breaks due to sensor inhibition is also analysed. It is further established that such data breaks do not improve the accuracy of the estimates of the along-track component during the transient phase. However, filter does not diverge during this period.
Following the analysis of the' filter performance, influence of Earth's oblateness on the measurement model studied. It is observed that the error in horizon points, due to spherical Earth approximation behave like a sinusoid of twice the orbital frequency alongwith a bias of about 0.21° in the case of a 900 kms sun synchronous orbit. The error in the 6 horizon points is shown to give rise to 6 sinusoids. Since the measurement model for a spherical earth is the simplest one, the feasibility of estimating these sinusoids along with the orbital state forms the next part of the thesis. Each sinusoid along with the bias is represented as a 3 state recursive equation in the following form
where i refers to the ith sinusoid and T the sampling interval. The augmented or composite state variable X consists of bias, Sine and Cosine components of the sinusoids. The 6 sinusoids together with the three dimensional orbital position vector in local coordinate frame then lead to a 21 state augmented Kalman Filter. With the 21 state filter, observability problems are experienced. Hence the magnetic field strength, which is a function of radial distance as measured by an onboard magnetometer is proposed as additional measurement. Subsequently, on using 6 horizon point measurements and the radial distance measurements obtained from a magnetometer and taking advantage of relationships between sinusoids, it is shown that a ten state filter (ie. 3 local orbital states, one bias and 3 zero mean sinusoids) can effectively function as an onboard orbit filter. The filter performance is investigated for circular as well as low eccentricity orbits. The 10-state filter is shown to exhibit a lag while following the radial component in case of low eccentricity orbits. This deficiency is overcome by introducing two more states, namely the radial velocity and acceleration thus resulting in a 12-state filter. Simulation studies reveal that the 12-state filter performance is very good for low eccentricity orbits. The lag observed in 10-state filter is totally removed. Besides, the 12-state filter is able to follow the changes in orbit due to orbital manoeuvers which are part of orbit acquisition plans for any mission.
29
Nagarajan, N. "Autonomous Orbit Estimation For Near Earth Satellites Using Horizon Scanners." Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/155.
Full textAbstract:
Autonomous navigation is the determination of satellites position and velocity vectors onboard the satellite, using the measurements available onboard. The orbital information of a satellite needs to be obtained to support different house keeping operations such as routine tracking for health monitoring, payload data processing and annotation, orbit manoeuver planning, and prediction of intrusion in various sensors' field of view by celestial bodies like Sun, Moon etc. Determination of the satellites orbital parameters is done in a number of ways using a variety of measurements. These measurements may originate from ground based systems as range and range rate measurements, or from another satellite as in the case of GPS (Global Positioning System) and TDUSS (Tracking Data Relay Satellite Systems), or from the same satellite by using sensors like horizon sensor^ sun sensor, star tracker, landmark tracker etc. Depending upon the measurement errors, sampling rates, and adequacy of the estimation scheme, the navigation accuracy can be anywhere in the range of 10m - 10 kms in absolute location.
A wide variety of tracking sensors have been proposed in the literature for autonomous navigation. They are broadly classified as (1) Satellite-satellite tracking, (2) Ground- satellite tracking, (3) fully autonomous tracking. Of the various navigation sensors, it may be cost effective to use existing onboard sensors which are well proven in space. Hence, in the current thesis, the Horizon scanner is employed as the primary navigation sensor-. It has been shown in the literature that by using horizon sensors and gyros, a high accuracy pointing of the order of .01 - .03 deg can be achieved in the case of low earth orbits. Motivated by such a fact, the current thesis deals with autonomous orbit determination using measurements from the horizon sensors with the assumption that the attitude is known to the above quoted accuracies.
The horizon scanners are mounted on either side of the yaw axis in the pitch yaw plane at an angle of 70 deg with respect to the yaw axis. The Field Of View (FOV) moves about the scanner axis on a cone of 45 deg half cone angle. During each scan, the FOV generates two horizon points, one at the space-Earth entry and the other at the Earth-space exit. The horizon points, therefore, lie• on the edge of the Earth disc seen by the satellite. For a spherical earth, a minimum of three such horizon points are needed to estimate the angular radius and the center of the circular horizon disc. Since a total of four horizon points are available from a pair of scanners, they can be used to extract the satellite-earth distance and direction.These horizon points are corrupted by noise due to uncertainties in the Earth's radiation pattern, detector mechanism, the truncation and roundoff errors due to digitisation of the measurements. Owing to the finite spin rate of the scanning mechanism, the measurements are available at discrete time intervals. Thus a filtering algorithm with appropriate state dynamics becomes essential to handle the •noise in the measurements, to obtain the best estimate and to propagate the state between the measurements. The orbit of a low earth satellite can be represented by either a state vector (position and velocity vectors in inertial frame) or Keplerian elements. The choice depends upon the available processors, functions and the end use of the estimated orbit information. It is shown in the thesis that position and velocity vectors in inertial frame or the position vector in local reference frame, do result in a simplified, state representation. By using the f and g series method for inertial position and velocity, the state propagation is achieved in linear form.
i.e. Xk+1 = AXK
where X is the state (position, velocity) and A the state transition matrix derived from 'f' and 'g' series. The configuration of a 3 axis stabilised spacecraft with two horizon scanners is used to simulate the measurements.
As a step towards establishing the feasibility of extracting the orbital parameters, the governing equations are formulated to compute the satellite-earth vector from the four horizon points generated by a pair of Horizon Scanners in the presence of measurement noise. Using these derived satellite-earth vectors as measurements, Kalman filter equations are developed, where both the state and measurements equations are linear. Based on simulations, it is shown that a position accuracy of about 2 kms can be achieved. Additionally, the effect of sudden disturbances like substantial slewing of the solar panels prior and after the payload operations are also analysed. It is shown that a relatively simple Low Pass Filter (LPF) in the measurements loop with a cut-off frequency of 10 Wo (Wo = orbital frequency) effectively suppresses the high frequency effects from sudden disturbances which otherwise camouflage the navigational information content of the signal. Then Kalman filter can continue to estimate the orbit with the same kind of accuracy as before without recourse to re-tuning of covariance matrices.
Having established the feasibility of extracting the orbit information, the next step is to treat the measurements in its original form, namely, the non-linear form. The entry or exit timing pulses generated by the scanner when multiplied by the scan rate yield entry or exit azimuth angles in the scanner frame of reference, which in turn represents an effective measurement variable. These azimuth angles are obtained as inverse trigonometric functions of the satellite-earth vector. Thus the horizon scanner measurements are non-linear functions of the orbital state. The analytical equations for the horizon points as seen in the body frame are derived, first for a spherical earth case. To account for the oblate shape of the earth, a simple one step correction algorithm is developed to calculate the horizon points. The horizon points calculated from this simple algorithm matches well with the ones from accurate model within a bound of 5%. Since the horizon points (measurements) are non-linear functions of the state, an Extended Kalman Filter (EKF) is employed for state estimation. Through various simulation runs, it is observed that the along track state has got poor observability when the four horizon points are treated as measurements in their original form, as against the derived satellite-earth vector in the earlier strategy. This is also substantiated by means of condition number of the observability matrix. In order to examine this problem in detail, the observability of the three modes such as along-track, radial, and cross-track components (i.e. the local orbit frame of reference) are analysed. This difficulty in observability is obviated when an additional sensor is used in the roll-yaw plane. Subsequently the simulation studies are carried out with two scanners in pitch-yaw plane and one scanner in the roll-yaw plane (ie. a total of 6 horizon points at each time). Based on the simulations, it is shown that the achievable accuracy in absolute position is about 2 kms.- Since the scanner in the roll-yaw plane is susceptible to dazzling by Sun, the effect of data breaks due to sensor inhibition is also analysed. It is further established that such data breaks do not improve the accuracy of the estimates of the along-track component during the transient phase. However, filter does not diverge during this period.
Following the analysis of the' filter performance, influence of Earth's oblateness on the measurement model studied. It is observed that the error in horizon points, due to spherical Earth approximation behave like a sinusoid of twice the orbital frequency alongwith a bias of about 0.21° in the case of a 900 kms sun synchronous orbit. The error in the 6 horizon points is shown to give rise to 6 sinusoids. Since the measurement model for a spherical earth is the simplest one, the feasibility of estimating these sinusoids along with the orbital state forms the next part of the thesis. Each sinusoid along with the bias is represented as a 3 state recursive equation in the following form
where i refers to the ith sinusoid and T the sampling interval. The augmented or composite state variable X consists of bias, Sine and Cosine components of the sinusoids. The 6 sinusoids together with the three dimensional orbital position vector in local coordinate frame then lead to a 21 state augmented Kalman Filter. With the 21 state filter, observability problems are experienced. Hence the magnetic field strength, which is a function of radial distance as measured by an onboard magnetometer is proposed as additional measurement. Subsequently, on using 6 horizon point measurements and the radial distance measurements obtained from a magnetometer and taking advantage of relationships between sinusoids, it is shown that a ten state filter (ie. 3 local orbital states, one bias and 3 zero mean sinusoids) can effectively function as an onboard orbit filter. The filter performance is investigated for circular as well as low eccentricity orbits. The 10-state filter is shown to exhibit a lag while following the radial component in case of low eccentricity orbits. This deficiency is overcome by introducing two more states, namely the radial velocity and acceleration thus resulting in a 12-state filter. Simulation studies reveal that the 12-state filter performance is very good for low eccentricity orbits. The lag observed in 10-state filter is totally removed. Besides, the 12-state filter is able to follow the changes in orbit due to orbital manoeuvers which are part of orbit acquisition plans for any mission.
30
Silveira, Augusto Wohlgemuth Fleury Veloso da. "Estudo comparativo de técnicas de estimativa do fluxo estatórico de MIT." Universidade Federal de Uberlândia, 2007. https://repositorio.ufu.br/handle/123456789/14606.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThis work shows and compares three different flux estimator algorithms developed for use in high-performance sensorless ac motor drives. The first algorithm uses a low pass filter with a very low cut off frequency to integrate the back electromotive force (emf). The second one uses a high pass filter to remove the offset present in the signal before it s integration. The third algorithm uses current and voltage model to estimate the flux of induction motor. These algorithms can be used to accurately measure the motor flux including magnitude and phase angle over a wide speed range. The performance of the algorithms is investigated, compared, and verified using simulation and experimental tests.
Este trabalho tem como objetivo apresentar uma comparação entre três algoritmos estimadores de fluxo estatórico diferentes. Estes algoritmos foram desenvolvidos para serem usados no projeto de acionamentos de alto desempenho, sem sensor de velocidade, para motores de indução. O primeiro algoritmo adotado utiliza um filtro passa baixa com uma freqüência de corte baixa para resolver a integração. O segundo algoritmo usa um filtro passa alta para retirar o offset do sinal de entrada do integrador puro. O terceiro algoritmo é um algoritmo híbrido que utiliza os modelos de tensão e corrente em paralelo para estimar o fluxo. Os algoritmos estimam fluxo estatórico em uma ampla faixa de freqüência de funcionamento do motor de indução e foram implementados na forma de simulação e experimentalmente para comparar o funcionamento dos mesmos em diferentes velocidades de operação do motor.
Mestre em Ciências
31
Novotný, Jakub. "Behaviorální modely aktivních prvků s nezávislým víceparametrovým elektronickým řízením." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241053.
Full textAbstract:
This thesis is focused on behavioral modelling of active elements with independent multi-parameter electronic control using comercially available components. In a first part of the thesis, CVDIBA, CVDOBA, CVCC and OC elements are discussed. The functionality is verified by simulations using OrCAD PSpice. Used components are diamond transistor OPA860, variable gain amplifier LMH6505, differencing amplifier AD830, low distortion differential driver AD8138, current conveyor EL2082 and current mode four quadrant multiplier EL4083. Four active elements are further built on PCB and measured. Some applications like low pass filter, high pass filter, all pass filter and reconfigurable filter.
32
Yeo, Woon Kwang. "A Generalized High Pass/Low Pass Averaging Procedure for Deriving and Solving Turbulent Flow Equations." Connect to resource, 1987. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1210098135.
Full text
33
Jašek, František. "Návrh nových aktivních filtrů pomocí grafů signálových toků." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218236.
Full textAbstract:
This master’s thesis describes the design of the frequency filters by the help of the graph of the signal flows. There are defined by modern components like GVC (Generalized Voltage Conveyor), GCC (Generalized Current Conveyor), CF (Current Follower), DO-CF (Dual-Output Current Follower), OTA (Operational Transconductance Amplifier), BOTA (Ballanced Operational Transconductance Amplifier) and CFTA (Current Follower Transconductance Amplifier), the graphs of the signal flows, which describe their activity in the thesis. In the other part of the thesis is illustrated the procedure of the design of the frequency filters by the help of the graphs of the signal flows. For the concrete design was selected in the first case as the active component double output current follower and in the second case the CFTA. There are noted all designed circuits of the frequency filters also their characteristic equations in this thesis. The activity of the selected circuits was remitted to the analysis in the simulation program called PSpice. Because the active components, with which was engaged in the design of the filter which doesn’t exist in the real form, that is why the UCC, which is sufficing for attestation of the function of the circuit, was used for the simulation. The simulation was implemented in the frequency range 10 Hz to 10 MHz.
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Nilson, Jonas. "Inter-Picture Prediction for Video Compression using Low Pass and High Pass Filters." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-331202.
Full textAbstract:
Most of the IP network traffic today consists of video content. In 2015 the videotraffic was estimated to be 70% of the Internet traffic and it is expected to rise past80% by 2020. The demand for high quality video, including high definition and ultrahigh definition, is steadily increasing with high resolution TV and computer monitorsbeing available to the general consumer. The video content streamed over theInternet have typically been compressed using a video encoder to reduce the bitsrequired to store and send the video. The increase of high resolution video contentalso requires updates to the video compression techniques. AVC is one of the mostcommonly used video compression standards, and its successor, HEVC, was able toachieve a 50% reduction of bitrate for the same perceived quality. Today there isongoing work to improve the compression efficiency of HEVC even further. Interpicture prediction, available in AVC and HEVC, is used to find redundant pixelsbetween adjacent frames in a video sequence and describe the movement of thepixels using motion vectors. This thesis focuses on exploring possible improvements to the inter prediction of thesuccessor to HEVC, currently under development, using low and high pass filteringwithin motion estimation and motion compensation to find potentially betterpredictions. The evaluation of the implemented filtering extension shows that themotion estimation and compensation filtering result can yield small benefits in somevideo sequences, with most of the video sequences in the test set resulting in smalllosses. There are still improvements to be made to the implementation, so there arepotentially more benefits to be gained by performing filtering within motionestimation and compensation.
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Bu, Huizheng. "Study of a new class of aperture-compensated microstrip low-pass and band-pass filters." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0008/MQ60887.pdf.
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Benites, Ayala Ivan Alejandro. "Nízkošumový zesilovač pro pásmo S." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400532.
Full textAbstract:
This master's thesis presents the design and the realization of a low noise amplifier (LNA) for the S band of radio frequency spectrum from 2.3 GHz to 2.4 GHz. This thesis is mainly focused on stability and impedance matching networks study. Ansoft Designer and ANSYS HFSS programs are used for this design to simulate the LNA. Different low noise devices are simulated in order to find the best results for the final design. Moreover, a coaxial cavity resonator is designed in the input of the LNA and works as a band pass filter. Finally, the LNA is fabricated and its properties compared with the simulation results.
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Chabbi, Charef. "VLSI NMOS hardware design of a linear phase FIR low pass digital filer." Ohio : Ohio University, 1985. http://www.ohiolink.edu/etd/view.cgi?ohiou1183749814.
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Chen, Mei-Show, and 陳美秀. "Multilayered-PWB Low-pass Filter for CATV." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/36635410175619388468.
Full textAbstract:
碩士國立交通大學
電信研究所
83
The 550-MHz low-pass filters can be used in the headend of transmitting control-center and the set-top tuners. There are two types of such filters. One is lumped filters and the other is ceramic multilayer distributed filters. Lumped filters are usually constructed using parallel-plate chip capacitors and air-wound inductors soldered into a small housing. Skilled manual labor is required o build and tune such a type of filters. Multilayer ceramic distributed filters have better quality, and smaller size, and are easier to fabricate than the lumped filters. They are, however, more expensive than the lumped filters. The techniques of processing multilayer ceramic distributed filters are well developed in Japan, but they are new in Taiwan. Due the high prices of multilayer ceramic distributed filters there is an urgent need to develop a low- cost and time-saving technique for low-pass filters. In Taiwan, the processing techniques of multilayer printed wiring board (ML-PWB) are well developed. By using the techniques of ML-PWB and transmission-line to replace air- wound inductor, we report here a design, fabrication and testing of a low-cost and time-saving multilayer PWB 550-MHz low-pass Filter.
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Tang, En-Hao, and 湯恩豪. "Design and Application of Low-pass filter." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/98861173774825879706.
Full textAbstract:
碩士國立雲林科技大學
電機工程系
103
This thesis proposes two types of low-pass filters (LPFs), one being an adjustable LPF designed for some particular industrial need and the other being an ordinary LPF designed for TV applications. The adjustable cut-off frequency range of the former was set within 23-36 MHz; for validation, another one having the adjustable cut-off frequency range of 700-900 MHz for long-term evolution (LTE) applications was also designed and fabricated. With the fixed cut-off frequency set to be 700 MHz, the latter was specially designed to be embedded in a VHF/UHF filter designed by New Power Electric Company. This low-pass filter was expected to suppress the UHF frequencies above 700 MHz. so that interferences coming from the LTE band can be avoided. The resulting VHF/UHF filter is a three-port device, which can receive VHF signals from the port connected to the VHF antenna having an input impedance of 300 ohms in 170-220 MHz and UHF signals from the port connected to the UHF antenna having an input impedance of 75 ohms in 470-700 MHz. For the LPF with adjustable cut-off frequencies, we first determined the fixed series component values required at the center frequency of the adjustable frequency range. Second, we determined the parallel capacitance values required at the lower-edge frequency of the adjustable frequency band and then replaced them by appropriate by varactor diodes. By tuning the capacitance values provided by the varactor diodes, we can adjust the cut-off frequency of the LPF. For the LPF with a fixed cut-off frequency, both 5-pole and 7-pole LPFs were designed and fabricated. The prototypes of these circuits were fabricated on 1.6-mm-thick FR4 substrates. The design processes were carried out with the aid of electromagnetic simulators Mcrowave Office, IE3D and ADS. The measurement agrees reasonably well with the simulation.
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Chen, Chieh-Ming, and 陳傑明. "Refinement to make optical low pass filter." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/21860145195324799168.
Full textAbstract:
碩士國立中央大學
機械工程研究所碩士在職專班
94
Summary These years, because of the high growth speed of digital products, the demand of OLPF filter is effect to increase very fast. This product is very difficult to manufacture that need many manpower to complete. This investigation focuses multi-quartz glued at the last production course, is to find a method to improve the manufacturing device, increase the efficiency and, decreasing the defect rate from man-made process. In this research, the design equipment has the automatic the gum machine and UV curing equipment. Understand a production process need in the actual situation production line; and design the equipment that is fit for production process. In terms of the ability of OEM production devices and useful advises, making embryo machine. Make use of experimental methods, get the best manufacturing process parameter, and make an equipments part that need to be improved to get an improvement, after this stage, then be quantity production machine. From small quantity trial-product to large numbers product, the aim is reducing man-made cost, raising the production capacity and accomplishing preliminary automation.
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NAND, MANISHA. "HIGH POWER HANDLING TUNABLE LOW PASS FILTER." Thesis, 2017. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16016.
Full textAbstract:
The goal of high-e ciency power ampli er operation from 30-520 MHz has been
addressed in the current design by the use of tunable reactive elements in the out-
put resonant network. Filtering at the target harmonic frequencies will be achieved
by maintaining a xed inductance and utilizing a PIN diode switching circuit to
selectively introduce di erent capacitance values, presenting the frequency-speci c
short and open circuits that will allow for power ampli er operation at the de-
sired fundamental frequency. This approach allows the power ampli er to cover
several octaves or more, achieving operation across a wide bandwidth and greatly
increasing the
exibility of the design for possible use in other frequency ranges.
The rst chapter gives the overview and objective of the lter. The speci ca-
tions of the lter required is listed in this chapter.
The second chapter gives an idea about the literature, several types of tech-
nologies used for tuning, how pin diode can be used as a switch, variation of series
resistance with frequency.
The third chapter has several methods of designing the lter , lter banks, and
which is suitable for desired speci cation.
The fourth chapter includes design of schematic in PADS and simulation in
simulation software ADS, tuning process.
At the end the last two chapters includes the response output of network
analyser and the project is concluded in the last chapter.
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Guo, Zhe-Yu, and 郭哲宇. "OTRA-Based Voltage Mode Low-Pass,Band-Pass, High-Pass, and Band-Reject Biquadratic Filter Structure." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/sdf5wb.
Full textAbstract:
碩士中原大學
電機工程研究所
98
Abstract This theory realized a voltage-mode second-order Butterworth filter contains low-pass, band-pass, high-pass and notch in the high frequency. In this circuit design, using OTRA to be the main active components that is the dual element of OTA . Operational Trans-Resistance Amplifier (Abbreviation: OTRA) have a Characteristic is virtual grounded at input extremities, it can reduce the parasitic effect for achieve the high accurate output signal. Using node analysis design method, we propose two Operational Trans-Resistance Amplifier and three capacitors, and four resistors, and the circuit is independent control. The simulation of this paper uses H-Spice with TSMC035 level 49 process to obtain the results, and compared with the theoretical by MATLAB., and then analyze the sensitivity of the active components for frequency response. We find this circuit have the advantage is low sensitivity, and consider the non-ideal effect of the active component to investigate the reason of distortion at high frequency. By analysis the gain-frequency from Rm, and simulate the circuit by using low pass model from Rm in MATLAB, find it is not enough to resolve, so add the band pass model from Rm, find it is because the inside non-ideal by OTRA . Then, we transform the resistor by MOS, because of it will improve the resistors in IC process is difficult for exactly manufacture and big size, besides the circuit still have high accurate output signal, but it still have the problem of distortion, consider the same reason ,find it is the same with the part of resistor . Finally, concluded this paper to explore a variety of better design in the future.
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Tai, Yung-hsen, and 戴詠軒. "Design of the Low-pass、Band-pass and high-pass Filter Structures using Adjustable Active elements." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/78452746488142436199.
Full textAbstract:
碩士中原大學
電機工程研究所
94
It is worthy of research to do the analogue circuit design using Operational Transconductance Amplifiers (OTAs) and Capacitors (Cs) because an OTA is equivalent to both an active element and a resistor leading to a more condensed integrated circuit without resistors ,and because the equivalent resistor value can be electronically tuned varying the bias current. Due to the difficulty to precisely fabricate the capacitance in integrated circuits, it becomes an important research work to find a tunable element for the replacement of the capacitor used to realize the s terms in transfer functions. The input-and-output relationship of an Operational Amplifier (OA) is shown as below. in which is the gain, the bandwidth , and the product of both gain and bandwidth . It is exhibited that, an OA can also be used to realize the s terms in transfer functions. Hence, the question is：“Is the variable , as he transconductance of an OTA , or not” ? In this thesis , we have found that the is variable tuning either the bias current or the inner compensation capacitance of an OA just like the variation of the trancondance of an OTA through the tuning of its bias current. Therefore, the capacitor with error fabricated in the integrated circuits can be replaced by the OA tunable through its inner bias current. The thesis is focused on he design of biquads using both tunable OAs and tunable OTAs ，leading to very precise output responses such as lowpass bandpass and highpass filtering signals . Finally, the H-spice simulation with TSMC035 process verifies the theoretical predictions.
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Shen, Jason, and 沈哲生. "A Compact Distributed Low-Pass Filter with Wide Stopband." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/60766135185673122385.
Full textAbstract:
碩士國立交通大學
電信工程系
89
A distributed parallel resonance circuit is used to design a very compact low-pass filter with cutoff frequency 0.5GHz. The circuit has a section of transmission line shunt with an interdigital capacitor connecting with two low-impedance lines at both of its terminals. A finite transmission zero can be generated near the passband edge so that the filter has a sharp transition response. In addition, the stopband can be extended to more than 6GHz by properly choosing the structural parameters of the circuit. The measured responses match with the simulation quite well.
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Lin, Chan-Hui, and 林展輝. "57Hz Low Pass Elliptic Filter Circuit Design of ECG." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/99561174078972319530.
Full textAbstract:
碩士中原大學
電機工程研究所
99
Abstract The precision of a output signal, making sure the signal is in or between the programed frequency band, is very important and top priority in analog filter circuit design field. To catch the subtle signal such as human body’s physiology by cardiograph, the precision is very important but often affected by test environment and facility itself. Therefore, the precision of the filter design is a crucial topic for research. OTA (Operational Transconductaance Amplifier) is best candidate for analog filter circuit design identified by savants recently. The main character of OTA is , where Io stands for output current, stands for positive input voltage, stands for negative input voltage, stands for trans-conductance value, and the input current I+=I-=0.The trans-conductance of OTA, it is the ration of output current ( ) and input voltage diviation , can be adjusted and controlled by bias current ( ).Some savants proposed the analytical synthesis of OTA-C circuit, which has some advantages like (1) controllable (2) a wide band of operation frequency (3) high input impedance (easy to cascade other circuit) (4) to minimize component counts (can decrease parasitical effect to minimum for raising the precision of the signal in circuit) The realization of circuit design in thise thesis, was based on the method of analytical synthesis,node analysis and transfer function represented by matrix. And decompose transfer function into three equations for simplifying circuit building. Finally, to combine those three circuits for completing whole elliptic filter circuit. With the advantage of node analysis to design the current-mode fourth-order elliptic low pass filter, we can have minimum component usage. Therefore, only few OTAs and capacitors can realize a 57Hz low pass filter. Before building the circuit, the simulations were based on the results of H-Spice and Matlab, and then to choose LM13700 (National Semiconductor Corp.) for OTA design selection. Finally, the connection between theoretics and experiment of proposed elliptic low pass filter were been proofed in this thesis. We hope it can be a valuable reference for those who join the research of elliptic filter afterward. Finally, this is designed of the 57Hz low-pass elliptic filter circuit, looking off the assembly line actually made of integrated circuits for use in the actual being in the electrocardiogram apparatus.
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Cheng, Mao-Yung, and 程茂墉. "Double Sampling Third Order Elliptic Function Low Pass Filter." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/59561694677398135323.
Full textAbstract:
碩士國立中山大學
電機工程學系研究所
100
Most discrete time filters use Switched Capacitor structures, but Switched capacitor circuits have finite sampling rate and high power consumption. In this paper we use Switched Current structure to increase sampling rate and reduce power consumption. In this paper, we use a Class-AB structure to compose a double sampling third order low-pass filter. In this paper there are two integrator types. Modified backward Euler and modified forward Euler integrators were realized with double sampling technology from the backward Euler and forward Euler integrators. Compared with other circuits, the circuit has low power supply、low power consumption 、high sampling speed. We employ HSPICE and MATLAB to simulate and design the circuit. We use TSMC 0.35μm process to implement this circuit. The power supply is 1.8V, the cut-off frequency is 3.6MHz, the sampling frequency is 72MHz, and the power consumption is 1.303mW.
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Huang, Shih Chun, and 黃世鈞. "5GHz Low-pass filter by CPW & dual-band low noise amplifier." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/34529253934090256418.
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Zhang, Zhi-Sheng, and 張智勝. "A low-area programmable low-pass-filter with automatic -3dB frequency calibration." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/rkuycn.
Full textAbstract:
碩士元智大學
電機工程學系甲組
107
For the application of 5G and the next generation wide-band communication system, this thesis proposes a programmable wide-bandwidth small-area low-pass-filter (LPF) and its corresponding passband auto-calibration circuit. By applying both analog bias and digital control code, the passband of the proposed LPF can achieve continuous tuning and with a wider tuning range. Instead of the conventional trans-conductance pair, the passive resistors and the grounded passive capacitors, the proposed LPF uses the inverters biased at their threshold levels, the active inductors and the active Miller capacitor. The parallel connection of active inductors and capacitors create an under-damping second-order impedance response, thereby reducing the transition band. The parasitic inductance of the active inductors could be adjusted via external digital controls. The miller capacitors are made of tri-stage inverters, the metal-insulator-metal (MIM) capacitors, the voltage-controlled MOS resistors. By analog control voltage, the effective capacitance of the miller capacitor can be adjusted continuously. In order to let the proposed LPF meet the specified passband frequency among different process corners and different operation conditions, we added an auto calibration circuit. The parasitic inductance of the active inductor and the parasitic capacitance of the active miller capacitor were overly adjusted to cause serious underdamp behavior, and the proposed LPF becomes a resonant oscillator. According to simulation and chip measured results, the passband frequency of the LPF during normal filtering operation and the oscillation frequency caused by overly tuning have a fixed ratio. As a result, once we use a feedback loop to control the oscillation frequency, the passband frequency would be proportional shifted to another specific frequency. The pass-band calibration circuit includes a replica LPF cell, a digital comparator, a counter and a pass-band control finite-state-machine (PC FSM), analog-to-digital converter. To verify the proposed LPF and the auto-calibration circuit, a 4-stage LPF template was realized in 0.18um CMOS technology, occupies an active area of 0.048mm2 and consumes a power of 3.45mW under 1.8V of supplies. The test chip measurement results show that the -3dB frequency can be continuously varied form 0.6MHz to 53.7MHz with a 3-bits of digital controls and a 0.7V-to-1.1V of analog controls. In addition, the simulation results show that under a 1MHz of reference clock, the auto calibration system takes 16 clock cycles to finish the passband calibration.The calibrated passband frequency has an error about 6% to the target frequency. The power consumption of the calibration system is about 3.7% to the LPF. Keywords: Low-Pass-Filter, LPF, Active Inductor, Miller Capacitor, Resonation, Oscillator, Auto-Calibration
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徐利君. "A seventh-order low pass filter for PRML read channel." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/80031120532400914221.
Full textAbstract:
碩士國立交通大學
電子工程系
90
Low voltage CMOS low pass filter using current-mode techniques is presented. The 680NHz cutoff frequency is achieved by using current-mode integrator as a building block of the current-mode biquad. A universal biquad is constructed from two basic building blocks, lossless and lossy differential current-mode integrators. Tuning of the biquad is obtained by changing the bias currents. The power consumption is 3.76mW with 2.5V supply voltage. The chip is fabricated in 0.25μm CMOS process.
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Zou, Yong-Tong, and 鄒永桐. "Making Optical Low-pass Filter by Thin-film Phase Grating." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/69438880677819675005.
Full textAbstract:
碩士國立中央大學
光電科學研究所
93
A new method utilizing the technique of coating process was applied to make a grating optical low-pass filter (GOLF). Using a metal mesh as a mask, the thin-film phase grating was fabricated with an advantage of simple and process for a mass-production. The modulation transfer function (MTF) was measured and proved it was agree well with the theoretical calculation. The GOLF was installed to a digital camera to take pictures of the circular zone plane (CZP) to show the ability of suppression of a Moiré pattern.