Laboratoire National Of Metrologie Systeme Of Reference Temps Espace

Le Touquet – Paris-Plage, France

Laboratoire National Of Metrologie Systeme Of Reference Temps Espace

Le Touquet – Paris-Plage, France

Time filter

Source Type

Makdissi A.,ELA Medical Sorin Group | Vernotte F.,University of Franche Comte | De Clercq E.,Laboratoire National Of Metrologie Systeme Of Reference Temps Espace
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control | Year: 2010

We analyze the Allan variance estimator as the combination of discrete-time linear filters. We apply this analysis to the different variants of the Allan variance: the overlapping Allan variance, the modified Allan variance, the Hadamard variance and the overlapping Hadamard variance. Based upon this analysis, we present a new method to compute a new estimator of the Allan variance and its variants in the frequency domain. We show that the proposed frequency domain equations are equivalent to extending the data by periodization in the time domain. Like the total variance, which is based on extending the data manually in the time domain, our frequency domain variance estimators have better statistics than the estimators of the classical variances in the time domain. We demonstrate that the previous well-know equation that relates the Allan variance to the power spectrum density (PSD) of continuous-time signals is not valid for real world discrete-time measurements and we propose a new equation that relates the Allan variance to the PSD of the discrete-time signals and allows computation of the Allan variance and its different variants in the frequency domain. © 2010 IEEE.


Guena J.,Laboratoire National Of Metrologie Systeme Of Reference Temps Espace | Rosenbusch P.,Laboratoire National Of Metrologie Systeme Of Reference Temps Espace | Laurent P.,Laboratoire National Of Metrologie Systeme Of Reference Temps Espace | Abgrall M.,Laboratoire National Of Metrologie Systeme Of Reference Temps Espace | And 5 more authors.
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control | Year: 2010

We report the operation of a dual Rb/Cs atomic fountain clock. 133Cs and 87Rb atoms are cooled, launched, and detected simultaneously in LNE-SYRTE's FO2 double fountain. The dual clock operation occurs with no degradation of either the stability or the accuracy. We describe the key features for achieving such a simultaneous operation. We also report on the results of the first Rb/Cs frequency measurement campaign performed with FO2 in this dual atom clock configuration, including a new determination of the absolute 87Rb hyperfine frequency. © 2006 IEEE.

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