Noise (4); Noises from Outer Source

Microseism source direction from noise cross-correlation

S U M M A R Y Inhomogeneous noise sources surrounding stations produce asymmetric amplitudes in crosscorrelation functions that yield preferential source directions. Here we show that preprocessing biases the dominant source direction estimate towards the source producing long-duration signals by down-weighting high-amplitude signals. Tests with both synthetic data and observations show that co...

I. Noise Source: Scream

Transient Noise Source Localization

Conventional beamforming systems for noise source localization are mostly based on frequency domain calculations. Additionally, narrowband assumptions concerning signal characteristics are often made to simplify the calculations, i.e. to be able to express a single time delay as a sole phase shift in the frequency domain as well. If necessary, a broadband system is then modeled as a composition...

F eb 2 00 4 FROM ( n + 1 ) - LEVEL ATOM CHAINS TO n - DIMENSIONAL NOISES

In quantum physics, the state space of a countable chain of (n+1) -level atoms becomes, in the continuous field limit, a Fock space with multiplicity n. In a more functional analytic language, the continuous tensor product space over IR of copies of the space C is the symmetric Fock space Γs(L 2(IR;C)). In this article we focus on the probabilistic interpretations of these facts. We show that t...

Low-noise synthesis of microwave signals from an optical source

Introduction: Low-phase-noise microwave sources are important in a variety of scientific and technological fields, including radar and remote sensing, communications and navigation, high-speed electronics, and the development of atomic frequency standards. At present, the lowest noise microwaves sources are synthesised from quartz oscillators or generated with dielectric or metallic resonant ca...