Rozprawy doktorskie na temat „Modulation discrète”
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Tabaa, Mohamed. "Conception d'un système de transmission ultra-large bande par impulsions orthogonales". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0375/document.
Pełny tekst źródłaIn this thesis, we propose a design methodology for communication architectures dedicated to wireless sensor network based on impulse radio techniques for UWB communications. The impulse technique proposed in this work relies on pulse shape modulation. The architecture design approach proposed in this thesis focuses on pulses shape and their generation, which is of major interest as it constitutes the carrier of the information exchanged. The study on the choice of pulse shape led us to propose two different architectures. The first one is based on orthogonal polynomials, more especially on the Hermite polynomials, for impulse generation, and on a correlation architecture for detection and recognition of transmitted impulses. The second architecture is based on discrete wavelet packet transform and can be used according two different modes, mono and multi-users. The use of both synthesis and analysis architectures for emitter and receiver, respectively, offers a new way for digital communications and allows the wavelet transform to ensure the impulses generation on the transmitter and their recognition on the receiver. A major interest point of the proposed technique is to facilitate the multi-users access to the ultra-wideband channel and to allow simultaneous communications (many-to-one, from the sensors to the sink) or broadcast (one-to-many, from the coordinator to the nodes) but without overloading the MAC layer. Hence, the proposed architecture is part of the interface between both PHY and MAC layers, and allows to release their specific design constraints
Fang, Yi-chin. "Performance evaluation of discrete IR optical system". Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270211.
Pełny tekst źródłaBengtsson, Daniel, i Daniel Landström. "Coding in a discrete multitone modulation system". Thesis, Luleå, 1996. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-62422.
Pełny tekst źródłaJenkin, Robin Brian. "On the application of the modulation transfer function to discrete imaging systems". Thesis, University of Westminster, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251647.
Pełny tekst źródłaForbes, Jason. "Discrete signal processing techniques for power converters : multi-carrier modulation and efficient filtering techniques". Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45446.
Pełny tekst źródłaKuznetsov, Nikita A. "Modulation and Coordination of Respiratory Rhythm with Discrete Finger Movements in Manual Precision Aiming". University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1291407910.
Pełny tekst źródłaSmecher, Graeme. "Discrete-time crossing-point estimation for switching power converters". Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115995.
Pełny tekst źródłaFor example, an audio amplifier typically receives its input from a digital source decoded into regular samples (e.g. from MP3, DVD, or CD audio), or obtained from a continuous-time signal using an analog-to-digital converter (ADC). In a switching amplifier based on Pulse-Width Modulation (PWM) or Click Modulation (CM), a signal derived from the sampled audio is compared against a deterministic reference waveform; the crossing points of these signals control a switching power stage. Crossing-point estimates must be accurate in order to preserve audio quality. They must also be simple to calculate, in order to minimize processing requirements and delays.
We consider estimating the crossing points of a known function and a Gaussian random process, given uniformly-spaced, noisy samples of the random process for which the second-order statistics are assumed to be known. We derive the Maximum A-Posteriori (MAP) estimator, along with a Minimum Mean-Squared Error (MMSE) estimator which we show to be a computationally efficient approximation to the MAP estimator.
We also derive the Cramer-Rao bound (CRB) on estimator variance for the problem, which allows practical estimators to be evaluated against a best-case performance limit. We investigate several comparison estimators chosen from the literature. The structure of the MMSE estimator and comparison estimators is shown to be very similar, making the difference in computational expense between each technique largely dependent on the cost of evaluating various (generally non-linear) functions.
Simulations for both Pulse-Width and Click Modulation scenarios show the MMSE estimator performs very near to the Cramer-Rao bound and outperforms the alternative estimators selected from the literature.
Pham, Dang Kien Germain. "Conversion analogique-numérique Sigma-Delta large bande appliquée à la mesure des non-linéarités des amplificateurs de puissance". Thesis, Paris, ENST, 2013. http://www.theses.fr/2013ENST0003/document.
Pełny tekst źródłaPower amplifiers, which are essential elements of any communication system, will play a crucial role in the development of future communication systems. Today improving power amplifiers requires technological advances at the circuit device level, but one also must consider a more global approach. In particular, advances in digital processing can now correct in the early stage of the communication chain some distortions that are generated downstream in the chain. Digital pre-distortion is a correction technique for power amplifiers that has a growing interest because of its completely digital implementation and of its gains in linearity and energy consumption. This technique requires a feedback path where the analog-to-digital converter is a critical element. This component must satisfy the constraints of high resolution , wide bandwidth, and high linearity. In this thesis, we propose a new architecture of analog-to-digital converter based on bandpass Delta-Sigma modulators. This architecture takes advantage of operating bandpass modulators that are designed to work in parallel, each focusing on different frequencies, but also of a particular cascading arrangement to eliminate the useful signal, which has a high power, in order to reduce dynamics constraints. High-level design and simulations were carried out for discrete time and continuous time systems and also required the development of appropriate simulation tools
Nathany, Sumit Kumar. "Design of a 14-bit fully differential discrete time delta-sigma modulator /". Online version of the thesis, 2006. https://ritdml.rit.edu/dspace/handle/1850/2799.
Pełny tekst źródłaQu, Zhen, i Ivan B. Djordjevic. "Four-Dimensionally Multiplexed Eight-State Continuous-Variable Quantum Key Distribution Over Turbulent Channels". IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2017. http://hdl.handle.net/10150/626439.
Pełny tekst źródłaTao, Junbing [Verfasser]. "Half-cycle-sampled discrete model of series-parallel resonant converter with optimized modulation and its control design / Junbing Tao". Paderborn : Universitätsbibliothek, 2018. http://d-nb.info/1155236297/34.
Pełny tekst źródłaKemp, Pieter Stephanus. "The design of an analogue class-D audio amplifier using Z-domain methods". Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20084.
Pełny tekst źródłaENGLISH ABSTRACT: The class-D audio power amplifier has found widespread use in both the consumer and professional audio industry for one reason: efficiency. A higher efficiency leads to a smaller and cheaper design, and in the case of mobile devices, a longer battery life. Unfortunately, the basic class-D amplifier has some serious drawbacks. These include high distortion levels, a load dependent frequency response and the potential to radiate EMI. Except for EMI, the aforementioned issues can be mitigated by the proper implementation of global negative feedback. Negative feedback also has the potential to indirectly reduce EMI, since the timing requirements of the output devices can be relaxed. This thesis discusses the design of a clocked analogue controlled pulse-width modulated class-D audio amplifier with global negative feedback. The analogue control loop is converted to the z-domain by modelling the PWM comparator as a sampling operation. A method is implemented that improves clip recovery and ensures stability during over-modulation. Loop gain is shaped to provide a high gain across the audio band, and ripple compensation is implemented to minimize the negative effect of ripple feedback. Experimental results are presented.
AFRIKAANSE OPSOMMING: Die klas-D klankversterker geniet wydverspreide gebruik in beide die verbruiker en professionele oudio industrie vir een rede: benuttingsgraad. ’n Hoër benuttingsgraad lei tot ’n kleiner en goedkoper ontwerp, en in die geval van draagbare toestelle, tot langer batterylewe. Ongelukkig het die basiese klas-D klankversterker ernstige tekortkominge, naamlik hoë distorsievlakke, ’n lasafhanklike frekwensierespons en die vermoë om EMI te genereer. Behalwe vir EMI kan hierdie kwessies deur die korrekte toepassing van globale negatiewe terugvoer aangespreek word. Negatiewe terugvoer het ook die potensiaal om EMI indirek te verminder, aangesien die tydvereistes van die skakel stadium verlaag kan word. Hierdie tesis bespreek die ontwerp van ’n geklokte analoog-beheerde pulswydte-modulerende klas-D klankversterker met globale negatiewe terugvoer. Die analoogbeheerlus word omgeskakel na die z-vlak deur die PWM vlakvergelyker as ’n monster operasie te modelleer. ’n Metode word geïmplementeer wat die stabiliteit van die lus verseker tydens oormodulasie. Die lusaanwins word gevorm om ’n hoë aanwins in die oudioband te verseker en riffelkompensasie word geïmplementeer om die negatiewe effek van terugvoerriffel teen te werk. Eksperimentele resultate word voorgelê.
Umansky, Alec. "HIGH BANDWIDTH PORTABLE TRANSMISSION SYSTEMS USE OF xDSL TECHNOLOGY IN MILITARY, INDUSTRIAL AND TELEMETRIC APPLICATIONS". International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/606418.
Pełny tekst źródłaThis paper introduces new telemetry (communications) equipment based on Digital Subscriber Loop DSL technology (high speed transmission over copper cables) for defense and industrial applications. A brief xDSL technology overview is followed with introduction of the new ‘P3’ product and its application, reviewing advantages of using copper as a communications medium whenever rapidly deployed data and voice links are essential. An Australian Army report, detailing a specific equipment deployment’s findings is reproduced as an independent reference material.
Umansky, Alec. "HIGH BANDWIDTH PORTABLE TRANSMISSION SYSTEMS USE OF xDSL TECHNOLOGY IN MILITARY AND INDUSTRIAL TELEMETRIC APPLICATIONS". International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606792.
Pełny tekst źródłaThis paper introduces new telemetry equipment based on Digital Subscriber Loop DSL technology (high speed transmission over copper cables) for military and industrial applications. A brief xDSL technology overview is followed with introduction of the new ‘P3’ product. A number of new applications for remote data transmission are presented and further highlighted in the Australian Army report detailing their recent equipment operational deployments.
Khushk, Hasham Ahmed. "Modulateur ΣΔ passe-haut et application dans la réception multistandards". Phd thesis, Télécom ParisTech, 2009. http://pastel.archives-ouvertes.fr/pastel-00006055.
Pełny tekst źródłaKrasňanský, Milan. "Radar Signal Processing for Radio Altimeter". Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2017. http://www.nusl.cz/ntk/nusl-363816.
Pełny tekst źródłaSurma, Dariusz. "Rekurencyjne metody ślizgającej analizy Wienera-Chinczyna". Rozprawa doktorska, [Nakł.aut.], 2013. http://dlibra.utp.edu.pl/Content/602.
Pełny tekst źródłaQu, Zhen, i Ivan B. Djordjevic. "High-speed continuous-variable quantum key distribution over atmospheric turbulent channels". SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/626486.
Pełny tekst źródłaOuzzif, Meryem. "Etude comparative des performances des liaisons SCM-VDSL (Single Carrier Modulation- Very high bit-rate Digital Subscriber Line) et DMT-VDSL (Discrete MultiTone) en présence de bruits impulsifs". Rennes, INSA, 2004. http://www.theses.fr/2004ISAR0002.
Pełny tekst źródłaThe latest DSL technology, called Very-high Digital Subscriber Line (VDSL), is intended to convey bit-rates up to 50 Mbps on the ordinary telephone access network. The standardization process is witnessing a competition between two modulation schemes: a single carrier modulation (SCM) and a multicarrier modulation (DMT). The VDSL transmissions performance depends on the electromagnetic environment as well as the implemented modulation. In particular, Impulse Noise, which is coupled on the copper lines, affects differently the SCM-VDSL and DMT-VDSL systems. The purpose of this thesis is to carry out a comparative study of the two systems in an Impulse Noise environment. First, the transmission environment characteristics are presented. The channel impulse response and the different noises liable to impair the VDSL transmission are detailed. The common transmission blocs to the two VDSL systems are explained. A second part is intended to the SCM-VDSL transmission modelling. The receiver of this system requires the implementation of an equalization structure to reduce the ISI. The consideration of Impulse Noise is carried out in the time domain. The developed simulation tool is validated through comparison with measurement results. A third part deals with the modelling of the Impulse Noise impact on DMT-VDSL transmissions. The modelling approach uses the characteristics of the DMT modulation and is led in the frequency domain. This method is simple to carry out since no equalization is needed. The two simulation tools are used in the last part to compare the two systems. First, the performance in terms of bit-rate of SCM-VDSL and DMT-VDSL is investigated for different line configurations (line length and presence of bridge taps) and for different transmission masks (with and without notches). The impact of Impulse Noise is examined for the two systems by considering the different parameters needed to optimize the robustness of the VDSL systems to this noise category
Baltolu, Anthony. "Etude et conception analogique d’architectures d’acquisition acoustique très faible consommation pour applications mobiles". Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0339/document.
Pełny tekst źródłaThe recent technological advances in microelectromechanical system (MEMS) microphones allow them to be used on a large sound amplitude range. Due to their lower noise level, it becomes possible to capture sound from a faraway distance, while their increased acoustic overload point gives them the ability to capture sound without saturation in a loud environment like a concert or a sport event. Thus, the electronic analog / digital conversion system connected to the microphone becomes the limiting element of the acoustic acquisition system performance. There is then a need for a new analog / digital conversion architecture which has an increased dynamic range. Furthermore, since more and more of these microphones are used in battery-powered devices, the power consumption limitation constraint becomes of high importance.In the audio frequency band, the sigma-delta analog / digital converters are the ones most able to provide a high dynamic range combined to a limited power consumption. They are split in two families: the discrete-time ones using switched-capacitors circuits and the continuous-time ones using more classical structures. This thesis concentrates on the study and the design of both of these two types of sigma-delta converters, with an emphasis on the low-power consumption, the low production cost (area occupied) and the circuit robustness, in sight of a mass production for portable devices.A discrete-time sigma-delta modulator design has been made, the latter reaching a signal to noise ratio of 100dB on a 24kHz frequency bandwidth, for a power consumption of only 480μW. To limit the power consumption, new inverter-based amplifiers are used, with an improved robustness against the variations of the fabrication process or the temperature. Amplifier specifications are obtained thanks to an accurate high-level model developed, which allows to avoid over-design while ensuring that the wanted performances are reached. Finally, a large oversampling ratio has been used to reduce the switched-capacitors area, lowering the modulator cost.After a theoretical study of the equivalence between discrete-time and continuous-time modulators, and of continuous-time modulators specificities, a design of the latter has been made too. It reaches a signal to noise ratio of 95dB on a 24kHz bandwidth, while consuming 142μW. To reduce the power consumption and the occupied area, a second-order loop filter is implemented using a single amplifier, and the quantizer uses a VCO-based structure that provides inherently an integrating stage. The VCO-based quantizer is made using digital cells, lowering the consumption and area, but is highly non-linear. This non-linearity has been handled by architectural choices to not influence the final modulator performances
Dai, Min. "Control of power converters for distributed generation applications". Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1124329850.
Pełny tekst źródłaБекус, Ростислав Володимирович, i Rostislav Bekus. "Метод підвищення якості передачі сигналів в бездротових локальних мережах". Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, 2020. http://elartu.tntu.edu.ua/handle/lib/34148.
Pełny tekst źródłaIn the qualification work of the master the concept of bases of information transfer in the wireless environment is opened. A study of the modern standard WI-Fi 802.11ac. It is established that the most pressing problem of local wireless networks today is the protection of transmitted data. Therefore, the main schemes of signal encryption and modulation are considered, the performance of the current standard is compared with the previous one. The advantage in the speed of information transmission and coverage area during multichannel operation is revealed. The basic standards of 802.11 wireless communication are investigated. The hypothesis of harm from health from the use of Wi-Fi was considered.
ВСТУП 8 РОЗДІ 1. АНАЛІТИЧНА ЧАСТИНА 10 1.1 Основи передачі ніформації в безпровідних технологіях 10 1.2 Класифікація безпровдіних технологій 14 1.2.1 Бездротові персональні мережі 15 1.2.2 Бездротові локальні мережі 16 1.2.3 Бездротові мережі масштабу міста 17 1.2.4 Бездротові глобальні мережі топологія 18 1.3 Порівняльний аналіз найбільш актуальних стандартів безпровідного зв'язку 18 1.4 Висновки до розділу 1 19 РОЗДІЛ 2. ОСНОВНА ЧАСТИНА 20 2.1. Основні терміни та елементи мережі 20 2.2. Актуальні стандарти безпровідних локальних мереж Wi-Fi 20 2.3. Актуальні стандарти бездротових мереж 21 2.3.1 IEEE 802.11g 22 2.3.2 IEEE 802.11n 23 2.3.3 IEEE 802.11ac 24 2.4 Об'єднання технологій безпеки Wi-Fi 26 2.4.1 Історія розвитку 26 2.4.2 Механізм аутентифікації WPA2 29 2.4.3 Механізм шифрування WPA2 35 2.4.4 Wardriving 37 2.4.5 Сніфери 38 2.4.6 Сніфери 39 2.5 Технології Wi-Fi які пливають на здоров'я людини 40 2.6. Висновки до розділу 2 41 РОЗДІЛ 3. НАУКОВО-ДОСЛІДНА ЧАСТИНА 42 7 3.1. Порівняння продуктивності 802.11 n і 802.11 ac 42 3.2 Висновки до розділу 3 45 РОЗДІЛ 4. СПЕЦІАЛЬНА ЧАСТИНА 46 4.1. Область застосування програмного забезпечення Microsoft Office Visio 46 4.2. Загальні принципи програми Microsoft Office Visio 48 4.3. Висновки до розділу 4 51 РОЗДІЛ 5. ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ 52 5.1. Охорона праці 52 5.2. Безпека в надзвичайних ситуаціях 54 5.3. Висновки до розділу 5 56 ЗАГАЛЬНІ ВИСНОВКИ 57 ПЕРЕЛІК ПОСИЛАНЬ 58 Додаток А. Копія тези конференції 60
Aimer, Younes. "Étude des performances d'un système de communication sans fil à haut débit". Thesis, Poitiers, 2019. http://www.theses.fr/2019POIT2269.
Pełny tekst źródłaThe request of the users in terms of rate, coverage and quality of service is growing exponentially, with increasing demand for electrical energy, to ensure networks link. In this context, new waveforms based on the OFDM modulation become widely popular and used intensively in recent radio communications architectures. However, these signals are sensitive to the power amplifier nonlinearities because of their high envelope fluctuations characterized by a high PAPR, which degrades the energy consumption and the transmitter efficiency.In this thesis, we first began by a state art of the PAPR reduction techniques. This presentation allowed us to propose a new method based on interleaving and coding techniques. The first contribution consists on the use of the interleaving technique using null-subcarriers for the transmission of the side information, while respecting the frequency specifications of the used standard. The second one is based on the conjunction of the Shaping technique and the Discrete Cosine Transform (DCT), with the aim of improving the performance of the system. Simulation results show that the use of these two techniques allows a significant gain in terms of PAPR reduction, which results in the improvement of the system efficiency. Finally, we presented an experimental study of the proposed techniques using an RF test bench with a commercial LDMOS 20 W PA, class AB operating at 3.7 GHz. The results obtained for the IEEE 802.11 standards show that the proposed approaches allow the transmission robustness and quality, while optimizing the power consumption
Rada, Dominik. "Přenosová technologie G.mgfast". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442370.
Pełny tekst źródłaJung, Jin Woo. "Modeling and control of fuel cell based distributed generation systems". Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1116451881.
Pełny tekst źródłaTitle from first page of PDF file. Document formatted into pages; contains xvi, 209 p.; also includes graphics. Includes bibliographical references (p. 202-209). Available online via OhioLINK's ETD Center
CHEN, JIAN-HUNG, i 陳建宏. "Wavelet-based Discrete Multitone Modulation". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/01521641416965102760.
Pełny tekst źródła國立臺灣大學
電信工程學研究所
87
Discrete multitone modulation systems have been widely applied to various communication systems. Many high speed transmission techniques use this scheme to transmit data over digital subscriber loops. For a nonideal linear filter channel, inter-symbol interference degrades system’s performance. It is known that multichannel systems have many advantages in such channel. In DMT systems, the available channel is subdivided into a number of subchannels, and a wisely chosen bit allocation policy is used to optimize the total transmission rate. It can be shown that the DMT system can achieve within 8 to 9 dB of channel capacity. Traditional DMT systems use DFT matrices to divide the channel into a number of subchannels. When channel is not ideal, some degree of redundancy known as cyclic prefix is added to cancel ISI. However, the receiving filters in such systems have poor frequency separation and the performance degrades significantly in the existence of narrow band interference. Therefore it is important to design DMT systems using more general filter banks. We proposed the wavelet-based DMT system which has better frequency separation property. In this thesis, we provide a systematic study on DMT based on a polyphase approach. We analysis the traditional DFT-based DMT in detail ,including it’s polyphase representation. And a modified DFT DMT is proposed with the same complexity. The most general wavelet-based DMT solutions with ISI free property will be derived. Two design approaches will be introduced, and design examples are given. In our approach, when the channel is frequency dependent, perfect reconstruction can be achieved by padding zeros as redundancy. This system outperforms the DFT-based DMT when there is narrow band interference.
Chou, Cheng-hsien, i 周政憲. "Integer modulation index CPM without discrete power component". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/81377811160634969336.
Pełny tekst źródła國立高雄第一科技大學
電腦與通訊工程研究所
100
Continuous phase modulation (Continuous Phase Modulation, CPM) signal has the characteristic of constant envelope, bandwidth efficiency, power efficiency and low side-lobe. Nevertheless, CPM with integer modulation indexes usually do not with the above properties. In recent years, the foreign savant Huang suggested to decompose CPM signals with integer modulation indexes into a set of PAM (Pulse Amplitude Modulation, PAM) waveforms. The PAM waveforms can be classified into two parts of pulses, one is data-dependent PAM pulses and the other is data-independent. The data-independent PAM pulse is correspondent to the discrete power spectral that is a waste of power. Therefore, most CPM with integer modulation index is not useful and does not discuss by the researchers. In fact, only binary CPFSK with unity modulation index has been employed in the pager system. In this thesis, we study new modulator by removing the data-independent PAM waveform and the Euclidean distance and spectrum are calculated. Since this new modulation no longer has the constant envelope property, a limiter is constructed to recover the constant envelope. It is found that the novel modulator has better distance yet with bandwidth expansion, as compared to the original CPM signals.
Milošević, Miloš. "Maximizing data rate of discrete multitone systems using time domain equalization design". Thesis, 2003. http://hdl.handle.net/2152/791.
Pełny tekst źródłaMilošević, Milos̆. "Maximizing data rate of discrete multitone systems using time domain equalization design". 2003. http://wwwlib.umi.com/cr/utexas/fullcit?p3116123.
Pełny tekst źródłaTsai, Tsung Lin, i 蔡宗霖. "Proton radiography using Discrete Range Modulation method – A Monte Carlo study". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/3f77ra.
Pełny tekst źródła長庚大學
醫學影像暨放射科學系
105
The advantages of the proton therapy are based on the characteristic proton Bragg peak. However, the proton range uncertainties which caused by many factors will lead to the dose deviation, even worse than photon therapy. This work has investigated the properties of proton radiography and water-equivalent path length (WEPL) to quantitatively assess the image quality and range uncertainties. We use Discrete Range Modulation (DRM) method for proton radiography benefited from CGMH wobbling and layer stacking techniques. We will report the advantages of DRM which compared to Continuous Range Modulation (CRM) method. In this study, we used MCNPX 2.7.0 to simulate the depth dose distribution by pencil beam geometry (PBG) on a water phantom of 40 x 40 x 40 cm2. According to ESS, beam energies from 70 to 230 MeV at 2.5MeV/step were obtained. In DRM method, we used the parameter based on Bragg Peak characteristics, R80. The mean proton range of different energies was obtained. DRM method to determine the WEPL is by using the relationship between the proton energy and energy deposition at 80% of the proximal fall off (E80) . The E80 will not vary while varying initial energy spread. For CRM method, a dose gradient plan was constructed to estimate relationship between WEPL and energy deposition. DRM and CRM were verified by different thickness of water phantoms, a step phantom and wedge phantoms. In DRM method, the difference of WEPL are < 2 mm, standard deviation in the images was found to be σ <0.5 mm . However, in CRM, difference of WEPL are >3mm, σ> 0.6 mm. SNR of DRM is more than three times of CRM. Proton radiography obtained using DRM method is more accurate and precise than those using CRM method. DRM method also can solve mixed beam problem owing to multiple Coulomb scattering.
Ding, Ming Evans Brian L. "Channel equalization to achieve high bit rates in discrete multitone systems". 2004. http://wwwlib.umi.com/cr/utexas/fullcit?p3142716.
Pełny tekst źródłaChiu, Jih-Chin, i 邱日進. "Distributed Feedback and Feedforward of Discrete-Time Sigma-Delta Modulator". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/12358399977956662187.
Pełny tekst źródła國立中山大學
電機工程學系研究所
100
This paper presents a distributed feedback and feedforward of discrete-time delta sigma modulator applications in the radio. We know the delta-sigma modulator using oversampling and noise shaping technique, thus we can relax the specifications of the components. This paper described the architectural differences and compare, the in-band signal is less sensitive to noise interference, and improve the resolution of the circuit. In the resonator, a simple structure with a small number of capacitor in resonator circuit. This paper uses the TSMC 0.18μm process parameters to the simulation, implementation, and measurement. Our fourth-order discrete-time delta-sigma modulator specifications as follows: the input signal frequency is 10.7MHz, the sampling frequency is 42.8MHz, the signal bandwidth is 200kHz, oversampling rate is 107, and one bit quantizer.
Yang, Dong-Sheng, i 楊東盛. "A Discrete-Time Lowpass Sigma-Delta Modulator for Voice Band Application". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/08911904882866438278.
Pełny tekst źródłaChen, Kuan-Hung, i 陳冠宏. "Design and Implementation of a Cognitive Radio Baseband Transceiver using Discrete Wavelet Multi-Tone Modulation". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/92355331877538212842.
Pełny tekst źródła國立臺灣大學
電機工程學研究所
95
In this thesis, design and implementation of a discrete wavelet multi-tone (DWMT) based baseband transceiver for cognitive radio applications are presented. The proposed system aims to provide wireless local-area network (WLAN service similar to IEEE 802.11 WLAN by exploiting the unused GSM spectrum. The DWMT modulation scheme originally proposed for wireline digital subscriber loop (DSL) applications is adopted as the modulation scheme. This modulation has stronger side-lobes attenuation than the popular OFDM modulation and thus generates much lower adjacent channel leakage, making it suitable for applications with dynamically-allocated spectrum. Signal and interference analysis of the adopted DWMT modulation is presented and signal processing techniques that tackle synchronization, equalization, and detection are developed. The entire DWMT-based baseband receiver is integrated and implemented in 0.18μm CMOS technology. Techniques such as hardware sharing, common term extraction, subcarrier constant multiplications removal, etc., are applied for hardware reduction. In addition, novel bi-directional SRAM-based delaylines are designed for memory saving. Measurement results of the fabricated receiver IC show that it functions well at 25.6 MHz operating frequency while drawing 165 mW from a 1.8 V supply voltage. When the whole 25.6 MHz bandwidth is available, this receiver IC can provide up to 153.6 Mbps of data transmission.
Chen, Kuan-Hung. "Design and Implementation of a Cognitive Radio Baseband Transceiver using Discrete Wavelet Multi-Tone Modulation". 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2507200716212900.
Pełny tekst źródłaHung, Yang-Cheng, i 洪揚程. "Generalization of Discrete-Time Sigma-Delta Modulator Non-Ideality Power Models to Various Sigma-Delta Modulator Architectures". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/68049481827279158962.
Pełny tekst źródła國立交通大學
電控工程研究所
100
The conventional high-level ΣΔM synthesis is mainly based on behavior simulation which is very time-consuming. Thus we propose model-based high-level ΣΔM synthesis. Model-based approach can be at the order of 104 times faster than simulation-based approach. Model-based method employs only mathematical models, which is set of ΣΔM non-ideality power models. Thus, the completeness of non-ideal power models is a must when we use model-based method to design ΣΔM. In this paper, major non-ideality power models of 2nd-order ΣΔM are discussed, and generalizations of those non-ideality power models to various ΣΔM topologies are also discussed. In addition, continuous-time ΣΔM is discussed in this paper, which incorporates comparison between discrete-time, continuous-time ΣΔM and loop filter design of continuous-time ΣΔM, and continuous-time ΣΔM behavioral model in MATLAB-Simulink environment.
Ding, Ming. "Channel equalization to achieve high bit rates in discrete multitone systems". Thesis, 2004. http://hdl.handle.net/2152/1219.
Pełny tekst źródłaYi, Ya-Wei, i 易亞維. "Design and Implementation of Predictive Current Controllers with Discrete-Space-Vector Modulation for Permanent Magnet Synchronous Motors". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/62tuge.
Pełny tekst źródła國立臺灣海洋大學
電機工程學系
107
In this thesis, predictive current controllers with discrete space-vector modulation for surface-mounted permanent magnet synchronous motors are proposed. The proposed controllers can apply three fixed-time voltage vectors in one sampling period, thus obtaining 37 composited voltage vectors. The proposed method is to improve the existing model-free current prediction methods and make detailed experimental comparisons with the model-based current prediction methods. The experimental platform is based on the TMS320F28379D microcontroller as the control core. Finally, the experimental results show that the proposed method can effectively improve the current-tracking performance.
Chang, Shing-Yun, i 張馨云. "A Seventh-Order Low-Noise Discrete-Time Delta-Sigma Modulator for Audio Applications". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/n82kac.
Pełny tekst źródła國立交通大學
電機工程學系
107
Due to our ears’ high ability of sound distinction, the resolution demand of the audio applications is higher and higher, such as audio equipment or speech recognition. To obtain a well performed SNR, we usually use the delta-sigma modulator to implement the ADC. When the order of the system is higher, the ability of de-noise is stronger. However, it will be more unstable as the order gets higher, so most people choose the third-order system to avoid this problem. Thus, the goal of this research is to achieve a very low noise floor (in-band noise power) with a seventh-order delta-sigma modulator and still stay stable. In this thesis, the design of the seventh-order delta-sigma modulator will be presented. It is utilized as the ADC in the analog front end of MEMS microphones. The design has to be medium-low power, low frequency, high SNR, and low noise to fit the demand of hearing applications. Results show for a 24kHz signal bandwidth the ADC achieves a dynamic range of 79dB, a peak signal-to-noise and distortion ratio of 68.1dB, and a in-band noise of -90.2dBFS with an oversampling ratio of 32 (sample rate of 1.536MHz). It was fabricated in a TSMC 0.18-m CMOS process with a 2.306mm2 active area, and dissipates 7.5mW from a 1.8-V power supply.
Wang, Sheng-Tsung, i 王聖琮. "A Discrete-Time 2-2 Sturdy-MASH Delta-Sigma Modulator with a Multi-bit Quantizer". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/q76z4b.
Pełny tekst źródłaLi, Chia-Hsun, i 李家勛. "Design of the Forth-Order 4-bit Discrete-Time Sigma-Delta Modulator for Audio Application". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/7h888e.
Pełny tekst źródła國立交通大學
電機工程學系
108
Due to the development of speech recognition systems in recent years, the demand of resolution for audio applications is getting higher and higher. To obtain a well performed SNR, we usually use the delta-sigma modulator to implement the ADC. When the order of the system is higher, the ability of noise shaping is stronger. However, the consideration of stability is very important as the order gets higher. A common solution to improve stability is to use a multi-bit quantizer. The goal of this research is to obtain the best resolution through balance between stability and circuit complexity. In this thesis, the design of the forth-order 4-bit sigma-delta modulator will be presented. It is utilized as the ADC in the analog front end of MEMS microphones. The design has to be medium-low power, low frequency, and high SNR to fit the demand of audio applications. Results show for a 24kHz signal bandwidth the ADC achieves a dynamic range of 57dB and a peak signal-to-noise and distortion ratio of 49.3dB with an oversampling ratio of 32 (sample rate of 1.536MHz). The chip was fabricated in a TSMC 0.18-m CMOS process with a 3.992mm2 active area and dissipates 7.7mW from a 3.3V/1.8V power supply.
Hu, Chun Hsiang, i 胡竣翔. "Applying the Discrete Range Modulation Method to Proton Radiography for a Clinical Pencil Beam Delivery System - a Monte Carlo Study". Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107CGU05770004%22.&searchmode=basic.
Pełny tekst źródła長庚大學
醫學影像暨放射科學系
107
Proton therapy provides the physical properties of the Bragg peak, and by adjusting the energy of the proton beam, the tumor has a good dose distribution. Proton beams for clinical treatment of patients may have range uncertainties, and if there is an incorrect safety margin for the proton therapy range, it will be worse than photon therapy. In this study has investigated whether the Discrete Range Modulation (DRM) method can be used in the clinic. We used PTSim to simulate the CGMH pencil beam scanning system. DRM method determine the WEPL by the different energy Bragg peak 80% range (R80) and calculate the WEPL from the energy deposition at 80% of the proximal fall off (E80) which without being affected by varying the initial energy spread. For the research, the effects of dose and fluence detectors for 1 x 106, 6 x 106, 3 x 107, particle numbers and different dose detector thicknesses for 0.5, 1, 2, 3, 5, 10 cm on the image quality of DRM proton radiography (pRG) by simulation of pure water phantom were investigated. A dose detector with a thickness of 2 mm and 6 x 106 particle numbers were selected as the setting for optimizing the simulation parameters. We also used DRM method to explain the WEPL of different thickness boundaries of the step phantom and pyramid phantom. The height of the X- and Y-axis magnets differs by the nozzle setting, which can increase the X and Y axis profile differently. Make sure DRM method is subject to beam divergence and cause the image enlargement. In the inhomogeneity phantom experiment, the smaller size of the phantom, the DRM pRG more blurred, that may cause by the proton passing through the phantom is insufficient. For DRM method, which can identify the WEPL distribution of various substances. Compared with the WEPL by the relative stopping power (RLSP), excluding titanium, all other materials have the range error less than 1 mm, proving that DRM method is better than the relative electron density (RED) to calculate the WEPL.
Acharya, Anirudh B. "Integrated Common And Differential Mode Filters With Active Damping For Active Front End Motor Drives". Thesis, 2011. https://etd.iisc.ac.in/handle/2005/2348.
Pełny tekst źródłaAcharya, Anirudh B. "Integrated Common And Differential Mode Filters With Active Damping For Active Front End Motor Drives". Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/2348.
Pełny tekst źródłaWang, Tao. "Low-power high-resolution delta-sigma ADC design techniques". Thesis, 2012. http://hdl.handle.net/1957/29740.
Pełny tekst źródłaGraduation date: 2012
Access restricted to the OSU Community at author's request from June 9, 2012 - June 9, 2014