Tesis sobre el tema "Phase spectrum"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores tesis para su investigación sobre el tema "Phase spectrum".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore tesis sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
Stark, Anthony. "Phase Spectrum Based Speech Processing and Spectral Energy Estimation for Robust Speech Recognition". Thesis, Griffith University, 2011. http://hdl.handle.net/10072/366490.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
Full Text
Cesbron, Fred́eŕique Chantal. "Pitch detection using the short-term phase spectrum". Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/15503.
Texto completoFletcher, Michael John. "Enhanced Implementations for Arbitrary-Phase Spread Spectrum Waveforms". Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90286.
Texto completoMaster of Science
This thesis presents a series of options for enhancing the implementation of arbitrary-phase spread spectrum waveforms, a highly-secure class of wireless technologies, in order to reduce design complexity with minimal loss, provide methods for real-time performance adaptations, and extend the traditional application space for increased security of communications in other networks. A number of enhanced hardware prototypes were implemented to provide measurable results, achieving substantial computational resource gains and design flexibility. Given the computational resources and power constraints of devices in the Internet of Things (IoT), the signal detection loss of 2.10 dB for reducing the hardware logic utilization of the brute force fallthrough correlator by more than 76% (and eliminating the need to dedicate computationally-expensive embedded multipliers) is a very reasonable trade. While the waveform is fundamentally designed for increased security, adapting to widespread and/or commercial use may allow some sacrifice of the signal’s ability to avoid interception/detection to improve performance in undesirable operating conditions. In a similar, yet reversed, case, injecting a watermarking signature at the physical layer (PHY) of less-secure wireless technologies for receiver-side authentication also proves to be beneficial.
Alsteris, Leigh y n/a. "Short-Time Phase Spectrum in Human and Automatic Speech Recognition". Griffith University. School of Microelectronic Engineering, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060727.090845.
Texto completo高樹豐 y Shu-fung Ko. "Emission morphologies and phase-resolved spectrum of gamma ray pulsar". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31224489.
Texto completoKo, Shu-fung. "Emission morphologies and phase-resolved spectrum of gamma ray pulsar /". Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B23476370.
Texto completoAlsteris, Leigh. "Short-Time Phase Spectrum in Human and Automatic Speech Recognition". Thesis, Griffith University, 2006. http://hdl.handle.net/10072/366602.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Microelectronic Engineering
Full Text
Wojcicki, Kamil Krzysztof. "Role of the Short-Time Phase Spectrum in Speech Processing". Thesis, Griffith University, 2011. http://hdl.handle.net/10072/366376.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
Full Text
Thayaparan, Subramaniam. "Delay-locked loop techniques in direct sequence spread-spectrum receivers". Thesis, Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21904108.
Texto completoTran, Ky-Anh. "A spread-spectrum clock generator using phase interpolation for EMI reduction". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91700.
Texto completoThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 123-125).
The spurious-free dynamic range of RF DAC's are limited by the heavy digital do- main switching, which interferes with the analog output signal. A design, layout and simulation of a spread-spectrum clock generator (SSCG) is presented. The SSCG modulates the clock frequency used to switch the digital blocks of the DAC in order to reduce electromagnetic interference (EMI) spurs at the analog output signal of the DAC. Leveraging on a phase control architecture rather than a traditional PLL, the SSCG system is shown to reduce the spectral height a divided down clock spur up to 19.6dB. The SSCG is designed in TSMC's 65nm CMOS process. It takes in quadrature, differential clocks at either 2.5GHz or 5GHz, and provides quadrature output clocks at 625MHz or 1.25GHz. The output spectrum of the clock can be attenuated up to 19.6dB relative to the spectrum of an unspread clock. The core of the SSCG is a phase interpolator, which takes in quadrature input clocks and interpolates between them to move the frequency around. To help process the signals before and after interpolation, the SSCG incorporates input variable gain lters, output restoration buffers and divide by 4 circuits. Extensive transistor and behavioral simulations are used to verify the design.
by Ky-Anh Tran.
M. Eng.
Radi, Haidar M. "Frequency hopping spread spectrum multiplexing for interferometric optical fibre sensor networks". Thesis, Manchester Metropolitan University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387483.
Texto completoXie, Zhaohua y 謝照華. "The study of phase-resolved spectra of gamma-ray pulsars". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B26665633.
Texto completoInberg, R. Brandon. "Enhanced step mode FTIR position control". Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/inberg/InbergR1205.pdf.
Texto completoZhao, Xianming, Mingji Yang, Tingxian Zhou y Liqun Meng. "SPREAD SPECTRUM COMMUNICATION SCHEME USING PHASESHIFTING SEQUENCE AND ITS PROPERTIES". International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/609223.
Texto completoThis paper analyzes the pseudo-random characteristic of m-sequence and proposes a spread spectrum communication scheme in which the phase-shifting sequences of msequence can be used as the spread spectrum code under given condition. Therefore, the available spread spectrum code set is expanded. It is theoretically proved that there are some advantages in using phase-shifting sequences instead of the conventional msequences or GOLD-sequences in spread spectrum communication system.
Leung, Chiu Hon. "The output frequency spectrum of a thyristor phase-controlled cycloconverter using digital control techniques". Thesis, University of Plymouth, 1985. http://hdl.handle.net/10026.1/2261.
Texto completodu, Plessis Laura. "Using emotional intelligence to support learners with Autism Spectrum Disorder in the Foundation Phase". Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/60939.
Texto completoDissertation (MEd)--University of Pretoria, 2017.
Early Childhood Education
MEd
Unrestricted
Handsel, Jennifer. "Anisotropy and spin relaxation in the condensed phase". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:8a268360-4e6c-4a18-96e2-f60a57b5b5df.
Texto completoKanaan, Mona N. "Cross-spectral analysis for spatial point-lattice processes". Thesis, [n.p.], 2000. http://dart.open.ac.uk/abstracts/page.php?thesisid=94.
Texto completoAgarwal, Shweta S. "QUADRATURE PHASE SHIFT KEYING-DIRECT SEQUENCE SPREAD SPECTRUM-CODE DIVISION MULTIPLE ACCESS WITH DISPARATE QUADRATURE CHIP AND DATA RATES". Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1134508354.
Texto completoClive, Sally. "Clinical phase 1, pharmacodynamic and pharmacokinetic evaluation of Antagonist G, a broad-spectrum neuropeptide growth factor antagonist". Thesis, University of Aberdeen, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325225.
Texto completoMa, Andy Kin-Wan. "Directional spectrum model for phase space modelling in Monte Carlo simulations for a medical linear accelerator in radiotherapy". Thesis, University of Surrey, 2006. http://epubs.surrey.ac.uk/843473/.
Texto completoLi, Hongxiang. "Performance of Multitone Direct Sequence Spread Spectrum in the Presence of Imperfect Carrier Synchronization". Ohio University / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1103057412.
Texto completoOprisan, Ana. "Fluctuations, Phase Separation and Wetting Films near Liquid-Gas Critical Point". ScholarWorks@UNO, 2006. http://scholarworks.uno.edu/td/435.
Texto completoValenta, Václav. "Frequency synthesis for cognitive multi-radio". Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00597461.
Texto completoKleinschmidt, Tristan Friedrich. "Robust speech recognition using speech enhancement". Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/31895/1/Tristan_Kleinschmidt_Thesis.pdf.
Texto completoDurgut, Suleyman. "Evidence of a narrow structure in ϓ(1S)l⁺l⁻ mass spectrum and CMS Phase I and II silicon detector upgrade studies". Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6411.
Texto completoCheng, Hui. "Data integration and visualization for systems biology data". Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77250.
Texto completoPh. D.
Zhou, Dan. "Certains études sur la minimalité et la propriété chaotique de dynamiques p-adicques et la régularité locale des series de Davenport avec translation de phase". Thesis, Paris Est, 2009. http://www.theses.fr/2009PEST0025.
Texto completoIn this thesis, we study the minimality and the chaotic property of p-adic dynamical systems and some multifractal properties of phase translated Davenport series. In the first part, we begin with the study of affine dynamical systems on Zp. We find a necessary and sufficient condition for such a system to be minimal. Furthermore, all its strictly ergodic components are exhibited when it is not minimal. In addition, we study monomial systems on the group 1 + pZp. Then transitive locally expanding polynomial systems are studied. It is proved that such a polynomial system, restricted to its Julia set, is conjugate to a subshift of finite type. In the second part, we study phase translated Davenport series. After having calculated the jump of the series at each point, we characterize the set of discontinuous points and get a sufficient and necessary condition for the series to be continuous on R. Furthermore, the pointwise convergence of the series is studied. Then we estimate the lower bound of the Hölder-exponent of rational translated Davenport series and get an upper bound estimation on the spectrum of singularity. The lower bound of the Hölder-exponent are also discussed for some irrational translated series
Mashayekhi-Nezamabadi, Kaveh. "The protein synthesis spectrum during the induction phase of somatic embryogenesis in Carrot (Daucus carota L.) cultures and the role of nitrogen forms for embryo development". [S.l.] : [s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=963447823.
Texto completoSargeant, H. "PREDETECTION RECORDING TECHNIQUES FOR GPS SIGNALS". International Foundation for Telemetering, 1986. http://hdl.handle.net/10150/615545.
Texto completoPredetection recording of spread-spectrum (SS) signals such as GPS transmissions is a desirable objective for both users and developers of equipment designed to receive such signals. (GPS user-equipment development is a lengthy process during which signal simulators are only partially useful.) Upon playback, GPS signals are used by the same or modified receivers so that acquisition, processing, detection and tracking loops can be altered to optimize the receiver parameters. Development of predetect SS signal recording systems is difficult to achieve in practice. Such systems not only must be of suitable phase linearity to preserve the signal content to be extracted but sometimes must also preserve the exact signal-to-noise ratio (SNR) characteristics of the recorded signals. Existing conventional test equipment is unsuitable for deriving value judgments of the quality of a predetect recording system’s output because the SS signal has a negative SNR. This paper reveals that it is possible to use, for this purpose, tape recorders now available on many test ranges in combination with auxiliary equipment similar to that designed for the U.S. Navy’s TRIDENT Program (recording C/A-code data from in-flight missile translators). The basic techniques are described in some detail to enable potential users to understand the necessary equipment concepts and evaluate the author’s approach in terms of their own applications.
De, Sanctis Silvia [Verfasser] y Hans Robert [Akademischer Betreuer] Kalbitzer. "Application of Singular Spectrum Analysis (SSA), Independent Component Analysis (ICA) and Empirical Mode Decomposition (EMD) for automated solvent suppression and automated baseline and phase correction from multi-dimensional NMR spectra / Silvia De Sanctis. Betreuer: Hans Robert Kalbitzer". Regensburg : Universitätsbibliothek Regensburg, 2011. http://d-nb.info/1030178941/34.
Texto completoHafez, Torbati Mohsen [Verfasser], Götz Silvester [Akademischer Betreuer] Uhrig y Kai Phillip [Gutachter] Schmidt. "Excitation spectrum and quantum phase transitions in the one-dimensional ionic Hubbard model : Continuous unitary transformations approach / Mohsen Hafez Torbati. Betreuer: Götz Silvester Uhrig. Gutachter: Kai Phillip Schmidt". Dortmund : Universitätsbibliothek Dortmund, 2014. http://d-nb.info/1107560314/34.
Texto completoЗгуровський, Артур Андрійович y Artur Zghurovskyi. "Метод кодування мовних сигналів для комунікаційних систем". Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, 2020. http://elartu.tntu.edu.ua/handle/lib/33949.
Texto completoThe master's thesis is devoted to the analysis of the method of coding speech signals for communication systems. The advantages and disadvantages of known coding methods are considered and the advantages of phase vocoders are highlighted. The parameters of voice signals used in their encoding in phase vocoders are evaluated.
ВСТУП РОЗДІЛ 1. АНАЛІТИЧНА ЧАСТИНА 1.1 Задача побудови вокодерів 1.2 Характеристики та структурні параметри голосу 1.3 Висновки до розділу 1. РОЗДІЛ 2. ОСНОВНА ЧАСТИНА.. 2.1 Параметризація мовного сигналу….. 2.2 НТК - архітектура і можливості. 2.3 Технологія моделювання систем розпізнавання мови з застосуванням інструментарію НТК… 2.4 Результати експериментальних досліджень…. 2.5 Висновки до розділу 2…. РОЗДІЛ 3.НАУКОВО-ДОСЛІДНА ЧАСТИНА…. 3.1 Вимірювання параметрів фільтрів мовних сигналів… 3.2 Вимірювання частоти основного тону…. 3.3 Формування збудливого сигналу... 3.4 Синтез: відновлення мовного сигналу.. 3.5 Висновки до розділу 3…. РОЗДІЛ 4.СПЕЦІАЛЬНА ЧАСТИНА…. 4.1 Метрологічне забезпечення наукового дослідженя… 4.2Побудова прикладного програмного забезпечення для розв’язування наукової задачі… 4.3 Висновки до розділу 4… РОЗДІЛ 5.ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІ-ЯХ…. 5.1 Охорона праці…. 5.1.1 Планування заходів з охорони праці. Види планування та контролю стану охорони праці… 5.1.2 Особливості розслідування та обліку нещасних випадків невиробничого характеру. 5.1.3 Пожежна сигналізація і зв'язок. Засоби гасіння пожеж. Протипожежне водопостачання. Первинні засоби пожежогасіння Автоматичні засоби пожежогасіння на об'єктах галузі...... 5.2 Безпека в надзвичайних ситуаціях……. 5.3 Висновки до розділу 5…. ЗАГАЛЬНІ ВИСНОВКИ…….. СПИСОК ВИКОРИСТАНИХ ДЖЕРЕЛ….. ДОДАТКИ.....
Čada, David. "Spektrální analyzátor do 500 MHz". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-221242.
Texto completoO'Hair, Richard Alfred John. "Studies in gas phase ion chemistry : a thesis presented for the degree of Doctor of Science in the Faculty of Science of the University of Adelaide /". Title page, table of contents and summary only, 2004. http://web4.library.adelaide.edu.au/theses/09SD/09sdo362.pdf.
Texto completoHENKE, EV. "Knock out - a missing C1s line in the photoelectron spectrum of aqueous chloral hydrate : Core electron spectroscopy of chloral hydrate, trichloroethanol and ethanol in aqueous solution and gas phase". Thesis, Uppsala University, Department of Physics and Astronomy, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-126257.
Texto completoChloral hydrate Cl3C-C(OH)2H in aqueous solution has been studied by photoelectron spectroscopy using synchrotron radiation. The expected separation between the two carbon 1s lines due to different chemical environments could not be observed in the aqueous solution, but was clearly seen in following gas phase measurements. NMR measurements excluded sample damage in the aqueous solution and support the image of coincidence of the two carbon lines. The coincidence of the two lines is discussed in terms of experimental resolution and change in chemical shift in the aqueous phase. The observations are further compared to measurements of trichloroethanol and ethanol, which both exhibit the same characteristic C-C bond and at least one hydroxyl group. The present data showed no clear evidence of change in chemical shift in aqueous solution as compared to the gas phase, but such an effect might not be completely excluded.
The liquid measurements were performed using a liquid micro-jet, a recently developed technique for accessing volatile liquids in a high vacuum environment as required for photoelectron spectroscopy. The set-up is described in detail.
During the present project, I was involved into planning and performing experiments, sample preparation, data analysis and discussion.
Al-Sharari, Hamed. "An implementation of acquisition using transform domain/cycle code shift keying system on a multipath channel". Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1177004799.
Texto completoKota, Akash. "Spectral Analysis of Bragg and Non-Bragg Orders in Dynamic Holography Using Photorefractive Materials". University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1470323121.
Texto completoLE, BLANC ALAIN. "Reactions unimoleculaires en phase gazeuse, de radicaux cations bifonctionnels : beta ceto-alcool, beta ceto-esters et de cations beta ceto-acylium". Paris 6, 1988. http://www.theses.fr/1988PA066349.
Texto completoMurach, Thomas. "Monoscopic Analysis of H.E.S.S. Phase II Data on PSR B1259–63/LS 2883". Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18484.
Texto completoCherenkov telescopes can detect the faint Cherenkov light emitted by air showers that were initiated by cosmic particles with energies between approximately 100 GeV and 100 TeV in the Earth's atmosphere. Aiming for the detection of Cherenkov light emitted by gamma ray-initiated air showers, the vast majority of all detected showers are initiated by charged cosmic rays. In 2012 the H.E.S.S. observatory, until then comprising four telescopes with 100 m² mirrors each, was extended by adding a much larger fifth telescope with a very large mirror area of 600 m². Due to the large mirror area, this telescope has the lowest energy threshold of all telescopes of this kind. In this dissertation, a fast algorithm called MonoReco is presented that can reconstruct fundamental properties of the primary gamma rays like their direction or their energy. Furthermore, this algorithm can distinguish between air showers initiated either by gamma rays or by charged cosmic rays. Those tasks are accomplished with the help of artificial neural networks, which analyse moments of the intensity distributions in the camera of the new telescope exclusively. The energy threshold is 59 GeV and angular resolutions of 0.1°-0.3° are achieved. The energy reconstruction bias is at the level of a few percent, the energy resolution is at the level of 20-30%. Data taken around the 2014 periastron passage of the gamma-ray binary PSR B1259-63/LS 2883 were analysed with, among others, the MonoReco algorithm. This binary system comprises a neutron star in a 3.4 year orbit around a massive star with a circumstellar disk consisting of gas and plasma. For the first time the gamma-ray spectrum of this system could be measured by H.E.S.S. down to below 200 GeV. Furthermore, a local flux minimum could be measured during unprecedented measurements at the time of periastron. High fluxes were measured both before the first and after the second transit of the neutron star through the disk. In the second case measurements could be performed for the first time contemporaneously with the Fermi-LAT experiment, which has repeatedly detected very high fluxes at this part of the orbit. A good agreement between measured fluxes and predictions of a leptonic model is found.
Chausse, Jean-Pierre. "Etude par une methode de melange, de l'organisation et des conformations moleculaires dans les mesophases hautement ordonnees". Clermont-Ferrand 2, 1987. http://www.theses.fr/1987CLF2E383.
Texto completoJerkstrand, Anders. "Spectral modeling of nebular-phase supernovae". Doctoral thesis, Stockholms universitet, Institutionen för astronomi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-64130.
Texto completoAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Accepted.
Lemiti, Mustapha. "Couches de dioxyde de silicium obtenues par dépôt chimique à partir d'une phase gazeuse (C. V. D. ) : élaboration et caractérisation". Lyon 1, 1985. http://www.theses.fr/1985LYO19022.
Texto completoCardenas, Olaya Andrea. "Digital instrumentation for the measurement of high spectral purity signals". Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCD019/document.
Texto completoImprovements on electronic technology in recent years have allowed the application of digital techniques in time and frequency metrology where low noise and high accuracy are required, yielding flexibility in systems implementation and setup. This results in measurement systems with extended capabilities, additional functionalities and ease of use.The Analog to Digital Converters (ADCs) and Digital to Analog Converters (DACs), as the system front-end, set the ultimate performance of the system in terms of noise. Moreover, most commercial platforms based on FPGA are clocked by quartz oscillators whose accuracy and frequency stability are not suitable for many time and frequency applications. In this case, it is possible to take advantage of the internal Phase Locked Loop (PLL) for generating the internal clock from an external frequency reference. However, the PLL phase noise could degrade the oscillator stability thereby limiting the entire system performance becoming a critical component for digital instrumentation. The information available currently in literature, describes in depth the features of these devices at frequency offsets far from the carrier. However, the information close to the carrier is a more important concern for time and frequency applications.In this frame, my PhD work is focused on understanding the limitations of the critical blocks of digital instrumentation for time and frequency metrology. The aim is to characterize the noise introduced by these blocks and in this manner to be able to predict their effects on a specific application. This is done by modeling the noise introduced by each component and by describing them in terms of general and technical parameters. The parameters of the models are identified and extracted through the corresponding method proposed accordingly to the component operation. This work was validated by characterizing a commercially available platform, Red Pitaya. This platform is an open source embedded system whose resolution and speed (14 bit, 125 MSps) are reasonably close to the state of the art of ADCs and DACs (16 bit, 350 MSps or 14 bit, 1 GSps/3GSPs) and it is potentially sufficient for the implementation of a complete instrument. The characterization results lead to the noise limitations of the platform and give a guideline for instrumentation design techniques.Based on the results obtained from the noise characterization, the implementation of a digital instrument for frequency transfer using fiber link was performed on the Red Pitaya platform. In this project, a digital implementation for the detection and compensation of the phase noise induced by the fiber is proposed. The beat note, representing the fiber length variations, is acquired directly with a high speed ADC followed by a fully digital phase detector. Based on the characterization results, it was expected a limitation in the phase noise measurement given by the PLL. First measurements of this implementation were performed using the 150 km-long buried fibers, placed in the same cables between INRiM and the Laboratoire Souterrain de Modane (LSM) on the Italy-France border. The two fibers are joined together at LSM to obtain a 300 km loop with both ends at INRiM. From these results the noise introduced by the digital system was verified in agreement with characterization results. Further test and improvements will be performed for having a finished system which is intended to be used on the Italian Link for Frequency and Time from Turin to Florence that is 642-km long and to its extension in the rest of Italy that is foreseen in the next future.Currently, a higher performance platform is under assessment by applying the tools and concepts developed along the PhD. The purpose of this project is the implementation of a state of the art phasemeter whose architecture is based on the DAC. The DAC characterization is under development and preliminary measurements are reported here
Remesh, Vikas. "Spectral phase control of nanoscale nonlinear optical responses". Doctoral thesis, Universitat Politècnica de Catalunya, 2020. http://hdl.handle.net/10803/669719.
Texto completoEl estudio de los procesos físicos impulsados por la luz generados en nanomateriales requiere pulsos láser más cortos (en el tiempo) con técnicas para adaptar sus características de fase y temporales ó espectrales en el volumen de interacción nanoscópica. Dichos estudios pueden abordar específicamente el aspecto de la coherencia de estados excitados en sistemas moleculares o de oscilaciones electrónicas colectivas en nanoresonadores plasmónicos. Abordar fenómenos coherentes no lineales con pulsos de femtosegundos de banda ancha, generalmente implica lograr interferencias constructivas o destructivas entre múltiples vías de absorción mediante manipulación de fase espectral. A pesar del progreso en el control espacio-temporal ultrarrápido de los procesos ópticos, un control coherente óptico sistemático y verdadero en un modo de plasmón dipolar fundamental seguía siendo desafiante debido al muy corto tiempo de decoherencia de la oscilación del plasmón en el rango de 25 fs. Desafortunadamente, la luminiscencia es un proceso incoherente y, por lo tanto, generalmente no ha sido explorado todavía para el control coherente a nanoescala de la respuesta de la antena. En primer lugar, demostramos que, en las nanoantenas de oro resonantes, el proceso de absorción de dos fotones puede ser coherente, siempre que la duración del pulso de excitación sea más corta que el tiempo de desfase de la oscilación del modo plasmonico. Aprovechando esta respuesta coherente, mostramos el control de la fase espectral pura de nanoantenas de oro resonantes, concolectando eficientemente de la fotoluminiscencia de dos fotones. Las nanoantenas dieléctricas de alto índice de refracción, por ejemplo, las nanoantenas de fosfuro de galio (GaP), han surgido recientemente como alternativas prometedoras a las nanoantenas plasmónicas que muestran scattering muy bajas extremadamente bajas en el rango visible y tienen altas no linealidades. También admiten resonancias magnéticas y eléctricas multipolares en el rango de frecuencia visible y NIR. Especialmente, las bajas scattering y las grandes no linealidades son prometedoras para una conmutación óptica ultrarrápida y un control puramente todo óptico de los nanodispositivos GaP. Aquí, primero, utilizamos la excitación de dos y tres fotones de los nanodiscos de GaP para probar la mejora de resonancia dependiente del tamaño de los nanodiscos de la emisión de segundo armónico y de la banda prohibida. A continuación, demostramos, mediante el control de fase espectral de la excitación pulsada de banda ancha, que las nanoantenas de GaP superaron a sus contrapartes metálicas en el generación de coherencias ópticas no lineales. A continuación, nuestros estudios numéricos sobre la mejora de SHG en las nanoantenas GaP indicaron que la mejora de SHG dependiente del tamaño es el resultado del confinamiento de campo eléctrico resonante en el volumen de nanoantena. El estudio del modelo de emisión angular, combinado con la polarimetría de nanoantenas resonantes reveló que la emisión de SHG resultante de la excitación con polarización lineal está predominantemente polarizada radialmente. El análisis modal multipolar a frecuencia SHG indicó la presencia de un dipolo eléctrico que oscila a lo largo del eje del disco, junto con contribuciones débiles de cuadrupolos y octopolos. Finalmente, el cambio espectral de SHG dependiente del tamaño confirmó la existencia de resonancias múltiples en estos nanodiscos. Aprovechando esta característica, los modos electromagnéticos multipolares que resuenan con fases relativas, después de una iluminación láser de banda ancha, pueden interferir y la interferencia puede controlarse mediante la modulación de fase espectral del campo de excitación para lograr la direccionalidad. Con una modulación de paso pi antisimétrica, se observó un cambio en el estado de polarización. Nuestros experimentos abren el camino para el control totalmente óptico de la radiación direccional de nanoantenas mediante el control de la interferencia multipolar en el régimen no lineal
Tiihonen, Mikael. "Spectral Management in Quasi-Phase-Matched Parametric Devices". Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4021.
Texto completoCoutinho, Fábio Rizental. "Um novo método ultrassônico para detecção da posição da interface em escoamentos bifásicos ar-água". Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/972.
Texto completoTécnicas de medição de velocidade baseadas em ultrassom vem sendo muito utilizadas atualmente para o estudo de escoamentos de fluidos devido ao seu caráter não intrusivo. Em escoamentos bifásicos ar-água, a grande dificuldade na aplicação dessa metodologia é resolver a que fase pertence a velocidade medida. Esse problema envolve a tarefa de determinar a posição da interface líquido-gás. O algoritmo de estimação de velocidade denominado de Velocity Matched Spectrum (VMS) se diferencia dos demais por apresentar como resultado um espectro de velocidades para cada volume amostral interrogado. Neste trabalho um método baseado no formato dessa curva espectral da velocidade é utilizado para gerar um mapeamento espaço-temporal, o qual, após aplicação de filtros espaciais, resulta na detecção acurada da posição da interface água-ar. Para isso, um sistema de medição que utiliza o estimador VMS foi desenvolvido e validado através de um experimento de escoamento em cilindro girante e de um escoamento horizontal monofásico turbulento. A ascensão de bolhas em líquido estagnado apresenta dificuldades na detecção da fronteira água-ar devido às mudanças abruptas na inclinação da interface da bolha no seu movimento de subida. É mostrado que a técnica proposta apresenta um erro RMS entre 1,71 a 3,39 e uma probabilidade de falha na detecção e de falsa detecção entre 0,89% a 11,9% na determinação da posição espaço-temporal da interface água-ar de um escoamento externo de ascensão de bolhas em líquido estagnado. Mostra-se que a exatidão na determinação é mantida mesmo no caso de um transdutor obstruído por uma chapa metálica, ou então, emitindo externamente a uma tubulação de acrílico.
Ultrasonic measurement techniques for velocity estimation are currently widely used in flow study due to its non-intrusive nature. The difficulty on the application of this methodology to a two-phase air-water flow is in deciding from which phase the velocity data measured comes from. This problem involves the task of evaluating gas-liquid interface position. The algorithm known as Velocity Matched Spectrum (VMS) is a velocity estimator that stands out from other methods by returning a spectrum of velocities for each interrogated volume sample. In this work a method based on velocity spectrum curve shape is used to generate a spatial-temporal mapping, which, after spatial filtering, yields an accurate contour of the air-water interface. Therefore, a measurement system that implements VMS estimator was developed and validated through a rotating cylinder and a horizontal single-phase pipe turbulent flow experiments. Interface detection of free-rising bubbles in quiescent liquid presents some difficulties for interface detection due to abrupt changes in interface inclination. It is showed that the proposed technique yields a RMS error between 1.71 to 3.39 and a probability of detection failure or false detection between 0.89% to 11.9% in determining the spatial-temporal gas-liquid interface position in the flow of free rising bubbles in stagnant liquid. This result is valid for both free path and with transducer emitting through a metallic plate or a Plexiglas pipe.
Métin, Jacques. "Etude structurale de fluorures ternaires de lanthanides et mecanismes de transfert d'energie gd**(3+) -> eu**(2+) dans rbgd : :(3)f::(10)". Clermont-Ferrand 2, 1987. http://www.theses.fr/1987CLF2E391.
Texto completoJia, Jianjun y 賈建軍. "The phase-resolved spectra of the crab pulsar". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B36379918.
Texto completoJia, Jianjun. "The phase-resolved spectra of the crab pulsar". Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36379918.
Texto completo