Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for subject:(bruit de quantification). Showing records 1 – 2 of 2 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


INP Toulouse

1. Ansaldi, Tobias. Compressible single and dual stream jet stability and adjoint-based sensitivity analysis in relationship with aeroacoustics : Stabilité d'un jet double flux et analyse de sensibilité sur la base d'un modèle adjoint en relation avec l'aeroacoustic.

Degree: Docteur es, Dynamique des fluides, 2016, INP Toulouse

La thèse est relative à la compréhension de la physique et au contrôle des émissions acoustiques dans les jets turbulents simples et double-flux. La génération du bruit est associé à des structures turbulentes de grandes tailles caractéristiques et à la turbulence de petites échelles. i Il est maintenant admis que les structures de grandes échelles sont des instabilités se propageant dans un champ moyen turbulent. Ici elle sont analysées sur la base de la théorie linéaire non locale appelées PSE pour Parabolized Stability Equations. Ces instabilités inflexionnelles associées à la présence de couche de cisaillement sont des modes de Kelvin-Helmhotz. Dans le cas du jet sous détentu des cellules de choc apparaissent et influencent très fortement les taux d'amplification et fréquences des modes propres. Divers écoulements sont investigués, de faible nombre de Mach au jet double-flux supersonique dont le champ moyen provient de simulation LES (Cerfacs). Le champ acoustique lointain est déterminé par l'analogie de Ffowcs-Williams-Hawkings. Ensuite une étude de sensibilité originales des instabilités et du bruits par rapport à divers forage locaux est produite sur la base deséquations de stabilité PSE adjointes. Les fortes sensibilités apparaissent dans les couches de cisaillements et aussi dans une moindre mesure autour des cellules de chocs. Les sensibilités sont plus complexes pour le jet double flux et dépendent du mode instable étudié lié soit au jet primaire soit au jet secondaire. Les sensibilités maximales se trouvent auvoisinage de la sortie de la tuyère et à la limite ou à l’extérieur du cne potentiel. En complément une étudesur le jet simple flux permet de mettre en rapport les approches de quantification d'incertitude et la sensibilité calculée par des équations adjointes. Les résultats de sensibilité vont permettre de contribuer à proposer des stratégies de contrôle aero-acoustique dans les jets de turboréacteurs.

This thesis leads to a better knowledge of the physic and of the control of acoustic radiation in turbulent single and dual-stream jets.It is known that jet noise is produced by the turbulence present in the jet that can be separated in large coherent structures and fine structures. It is also concluded that these large-scale coherent structures are the instability waves of the jet and can be modelled as the flow field generated by the evolution of instability waves in a given turbulent jet. The growth rate and the streamwise wavenumber of a disturbance with a fixed frequency and azimuthal wavenumber are obtained by solving the non-local approach called Parabolized Stability Equations (PSE). Typically the Kelvin-Helmholtz instability owes its origin into the shear layer of the flow and, moreover, the inflection points of the mean velocity profile has a crucial importance in the instability of such a flow. The problem is more complex in case of imperfectly expanded jet where shock-cells manifest inside the jet and strongly interaction with the instability waves has been observed. Several…

Advisors/Committee Members: Airiau, Christophe (thesis director).

Subjects/Keywords: Analyse de sensibilité; Analyse de la stabilité; Analogy aéroacoustique; Bruit de jet; Quantification de l'incertitude; Sensitivity analysis; Stability analysis; Aeroacoustic analogy; Jet noise; Uncertainty Quantification

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Ansaldi, T. (2016). Compressible single and dual stream jet stability and adjoint-based sensitivity analysis in relationship with aeroacoustics : Stabilité d'un jet double flux et analyse de sensibilité sur la base d'un modèle adjoint en relation avec l'aeroacoustic. (Doctoral Dissertation). INP Toulouse. Retrieved from http://www.theses.fr/2016INPT0081

Chicago Manual of Style (16th Edition):

Ansaldi, Tobias. “Compressible single and dual stream jet stability and adjoint-based sensitivity analysis in relationship with aeroacoustics : Stabilité d'un jet double flux et analyse de sensibilité sur la base d'un modèle adjoint en relation avec l'aeroacoustic.” 2016. Doctoral Dissertation, INP Toulouse. Accessed November 20, 2018. http://www.theses.fr/2016INPT0081.

MLA Handbook (7th Edition):

Ansaldi, Tobias. “Compressible single and dual stream jet stability and adjoint-based sensitivity analysis in relationship with aeroacoustics : Stabilité d'un jet double flux et analyse de sensibilité sur la base d'un modèle adjoint en relation avec l'aeroacoustic.” 2016. Web. 20 Nov 2018.

Vancouver:

Ansaldi T. Compressible single and dual stream jet stability and adjoint-based sensitivity analysis in relationship with aeroacoustics : Stabilité d'un jet double flux et analyse de sensibilité sur la base d'un modèle adjoint en relation avec l'aeroacoustic. [Internet] [Doctoral dissertation]. INP Toulouse; 2016. [cited 2018 Nov 20]. Available from: http://www.theses.fr/2016INPT0081.

Council of Science Editors:

Ansaldi T. Compressible single and dual stream jet stability and adjoint-based sensitivity analysis in relationship with aeroacoustics : Stabilité d'un jet double flux et analyse de sensibilité sur la base d'un modèle adjoint en relation avec l'aeroacoustic. [Doctoral Dissertation]. INP Toulouse; 2016. Available from: http://www.theses.fr/2016INPT0081


EPFL

2. Pesenti, Sergio. Hybrid continuous-discrete-time multi-bit delta-sigma A/D converters with auto-ranging algorithm.

Degree: 2007, EPFL

In wireless portable applications, a large part of the signal processing is performed in the digital domain. Digital circuits show many advantages. The power consumption and fabrication costs are low even for high levels of complexity. A well established and highly automated design flow allows one to benefit from the constant progress in CMOS technologies. Moreover, digital circuits offer robust and programmable signal processing means and need no external components. Hence, the trend in consumer electronics is to further reduce the part of analog signal processing in the receiver chain of wireless transceivers. Consequently, analog-to-digital converters with higher resolutions and bandwidths are constantly required. The ultimate goal is the direct digitization of radio frequency signals, where the conversion would be performed immediately after the front-end amplifier. ΔΣ-modulation-based converters have proved to be the most suitable to achieve the required performance. Switched-capacitor implementations have been widely used over the last two decades. However, recent publications and books have shown that continuous-time architectures can achieve the same performance with lower power consumption. Most designs found throughout the literature use a single- or few-bit internal quantizer with a high-order modulation. As a result, in order to achieve the resolutions and bandwidths required today, the sampling frequency must exceed 100MHz. This approach leads to non-negligible power consumption in the clock generation. Moreover, the presence of such fast squared signals is not suitable for a system-on-chip comprising radio frequency receivers. In this thesis we propose a low-power strategy relying on a large number of internal levels rather than on a high sampling frequency or modulation order. Besides, a hybrid continuous-discrete-time approach is used to take advantage of the accuracy of switched-capacitor circuits and the low power consumption of continuous-time implementation. The sensitivity to clock jitter brought about by the continuous-time stage is reduced by the use of a large number of levels. An auto-ranging algorithm is developed in this thesis to overcome the limitation of a large-size quantizer under low-voltage supply. Finally, the strategy is applied to a design example addressing typical specifications for a Bluetooth receiver with direct conversion. Advisors/Committee Members: Kayal, Maher.

Subjects/Keywords: analog-to-digital conversion; delta-sigma modulation; multi-bit; quantization noise; hybrid architecture; continuous-time; discrete-time; full clock-cycle sampling; double-sampling; digital calibration; auto-ranging algorithm; tracking quantizer; dynamic element matching; spectral shaping; tree-structured encoder; segmented DAC; Bluetooth; WCDMA; GSM; EDGE; comparator; CMOS technology; fully-differential amplifier; transconductance amplifier; conversion analogique-numérique; modulation delta-sigma; multibit; bruit de quantification; architecture hybride; temps continu; temps discret; échantillonnage sur deux demi périodes; double échantillonnage; calibration numérique; algorithme d'ajustement automatique d'amplitude; quantificateur; appariement dynamique; mise en forme spectrale; encodeur à structure en arbre; CAN segmenté; Bluetooth; WCDMA; GSM; EDGE; comparateur; technologie CMOS; amplificateur différentiel symétrique; amplificateur à transconductance

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Pesenti, S. (2007). Hybrid continuous-discrete-time multi-bit delta-sigma A/D converters with auto-ranging algorithm. (Thesis). EPFL. Retrieved from http://infoscience.epfl.ch/record/110153

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Pesenti, Sergio. “Hybrid continuous-discrete-time multi-bit delta-sigma A/D converters with auto-ranging algorithm.” 2007. Thesis, EPFL. Accessed November 20, 2018. http://infoscience.epfl.ch/record/110153.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Pesenti, Sergio. “Hybrid continuous-discrete-time multi-bit delta-sigma A/D converters with auto-ranging algorithm.” 2007. Web. 20 Nov 2018.

Vancouver:

Pesenti S. Hybrid continuous-discrete-time multi-bit delta-sigma A/D converters with auto-ranging algorithm. [Internet] [Thesis]. EPFL; 2007. [cited 2018 Nov 20]. Available from: http://infoscience.epfl.ch/record/110153.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Pesenti S. Hybrid continuous-discrete-time multi-bit delta-sigma A/D converters with auto-ranging algorithm. [Thesis]. EPFL; 2007. Available from: http://infoscience.epfl.ch/record/110153

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.