Results 31 to 40 of about 3,059,110 (191)
Time-frequency analysis on the adeles over the rationals [PDF]
, 2018 We show that the construction of Gabor frames in $L^{2}(\mathbb{R})$ with generators in $\mathbf{S}_{0}(\mathbb{R})$ and with respect to time-frequency shifts from a rectangular lattice $\alpha\mathbb{Z}\times\beta\mathbb{Z}$ is equivalent to the ...
Enstad, Ulrik B. R. +2 more
core +4 more sources
Design of a vacuum system for space active hydrogen maser
Frontiers in Physics, 2022 With the high precision and stability of its frequency signal outputs, active hydrogen maser plays an important role in such fields as timing, satellite navigation, and communication. However, it needs to be lighter so as to be applied in space.
Haohui Que +11 more
doaj +1 more source
Global testing against sparse alternatives in time-frequency analysis [PDF]
, 2016 In this paper, an over-sampled periodogram higher criticism (OPHC) test is proposed for the global detection of sparse periodic effects in a complex-valued time series.
Cai, T. Tony +2 more
core +3 more sources
Precision measurement of transverse velocity distribution of a strontium atomic beam
AIP Advances, 2014 We measure the transverse velocity distribution in a thermal Sr atomic beam precisely by velocity-selective saturated fluorescence spectroscopy. The use of an ultrastable laser system and the narrow intercombination transition line of Sr atoms mean that ...
F. Gao +7 more
doaj +1 more source
Recent Advances Concerning the 87Sr Optical Lattice Clock at the National Time Service Center
Applied Sciences, 2018 We review recent experimental progress concerning the 87Sr optical lattice clock at the National Time Service Center in China. Hertz-level spectroscopy of the 87Sr clock transition for the optical lattice clock was performed, and closed-loop operation of
Yebing Wang +4 more
doaj +1 more source
Optical Phase-Space-Time-Frequency Tomography
, 2011 We present a new approach for constructing optical phase-space-time-frequency tomography (OPSTFT) of an optical wave field. This tomography can be measured by using a novel four-window optical imaging system based on two local oscillator fields balanced ...
Beck +25 more
core +1 more source
Analysis of Narrow-Line Laser Cooling and Trapping of Sr Atoms in Microgravity Environments
Applied Sciences, 2020 Obtaining ultracold alkaline earth(-like) atoms in space encounters the problem of performing narrow-line laser cooling in microgravity environments ( μ -gEs).
Jie Ren +3 more
doaj +1 more source
Analysis of time-frequency scattering transforms
, 2018 In this paper we address the problem of constructing a feature extractor which combines Mallat's scattering transform framework with time-frequency (Gabor) representations. To do this, we introduce a class of frames, called uniform covering frames, which
Czaja, Wojciech, Li, Weilin
core +1 more source
Time-frequency analysis of chaotic systems
, 2002 We describe a method for analyzing the phase space structures of Hamiltonian systems. This method is based on a time-frequency decomposition of a trajectory using wavelets.
Chandre, C., Uzer, T., Wiggins, S.
core +3 more sources
Quantum-limited time-frequency estimation through mode-selective photon measurement [PDF]
, 2018 By projecting onto complex optical mode profiles, it is possible to estimate arbitrarily small separations between objects with quantum-limited precision, free of uncertainty arising from overlapping intensity profiles. Here we extend these techniques to
Ansari, Vahid +7 more
core +2 more sources