The Characterization Of Clock Behavior With The Dynamic Allan Variance
L. Galleani (1), P. Tavella (2)
(1) Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino, ITALY
(2) Istituto Elettrotecnico Nazionale (IEN), Strada delle Cacce 91, 10135 Torino, ITALY
Abstract - We introduce the Dynamic Allan Variance, a quantity that characterizes the
variation in time of the stability of an atomic clock. We connect the Dynamic Allan Variance
to the Wigner spectrum, a time-frequency representation that can reveal the time-varying
frequencies generally present in the clock error noise under nonstationary conditions.
We also propose a practical implementation of the Dynamic Allan Variance for quasi-stationary
clock noises, and we show numerical results that prove the validity of our approach, both on
simulated and real data.
Proc. Joint Meeting European Frequency and Time Forum and IEEE Frequency Control Symposium, May 2003
http://www.ieee-uffc.org/archive/fc/2003.htm
Figure 1. A series of phase data x(t) affected by time-varying white noise
Figure 2. Dynamic Allan Deviation of the phase series x(t) of Fig. 1.
The DAVar estimator clearly tracks the nonstationarity.
Zip file containing the Matlab code for evaluating the Dynamic Allan Variance :
DAVAR.zip
