Lorenzo Galleani
Politecnico di Torino
Torino, Italy
The dynamic Allan variance becomes an ITU standard
The dynamic Allan variance (DAVAR), a transform for the characterization of the time-varying stability of atomic clocks and, in general, of nonstationary random processes, is now an International Telecommunication Union (ITU) standard, under Recommendation ITU-R TF.538-4, “Measures for random instabilities in frequency and time (phase).” (See pages 8-9 of the ITU Recommendation.)
Time-frequency analysis of the impulse response
This paper discusses the time-frequency structure of the impulse response for single-input single-output (SISO) and multiple-input multiple-output (MIMO) systems. Both for SISO and MIMO systems, the time-varying spectrum of the impulse response is made by frequency-translated versions of a T-shaped function of time and frequency, the key representation of resonance phenomena.