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Theses

Traitement de Signal Appliqué aux Etalons Primaires de Fréquence : Amélioration de leur Exactitude et de leur Stabilité

Abstract : The definition of the second is based, since 1967. on the atomic proprieties of the caesium atom. An atomic clock is the devise that realises this definition. This is achieved with a limited precision because of many perturbations. Every enhancement in tue performance of atomic docks is welcome bv the present and future applications that use these docks.
The aim of this thesis work is to enhance the performances of the primary frequency standard (JPO) of the BNM-LPTF.
The resuits obtained during this thesis could be resumed by the following performances:
A global uncertainty of 6,3 x 10-15 and a short term stability of 3 x 10-13/sqrt(t) where t is the integration time in seconds. Theses enhancements make our JPO frequency standard the best atomic beam frequency standard in the world.
Theses good resuits are due to many factors:
1) A control of the Micro-wave leakage level inside the Ramsey cavity which was designed and realized during this thesis.
2) New signal processing methods (regularization, inverse problems, cepstral analysis. ...) that we have introduced in the evaluation process.
3) A new study of the frequency control loop based on a dynamical model that was developed to represent the different noises contribution to the stability. This study was materialized by the implementation (hardware and software) of a digital servo loop of a very high quality.
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https://tel.archives-ouvertes.fr/tel-00011625
Contributor : Alaa Makdissi <>
Submitted on : Thursday, February 16, 2006 - 3:27:42 PM
Last modification on : Monday, December 14, 2020 - 9:45:45 AM
Long-term archiving on: : Saturday, April 3, 2010 - 8:03:27 PM

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  • HAL Id : tel-00011625, version 1

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Alaa Makdissi. Traitement de Signal Appliqué aux Etalons Primaires de Fréquence : Amélioration de leur Exactitude et de leur Stabilité. Traitement du signal et de l'image [eess.SP]. Université Paris Sud - Paris XI, 1999. Français. ⟨tel-00011625⟩

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