Frequency Content of Randomly Scattered Signals

Frequency Content of Randomly Scattered Signals

The statistical properties of acoustic signals re ected by a randomly layered medium are analyzed when a pulsed spherical wave issuing from a point source is incident upon it. The asymptotic analysis of stochastic equations and geometrical acoustics is used to arrive at a set of transport equations that characterize multiply scattered signals observed at the surface of the layered medium. The r...

Frequency Content of Randomly Scattered Signals I

Signals reflected from a randomly layered medium are nonstationary stochastic processes that can have very complicated structure. In [l, 21 we considered pulse reflection from a randomly layered half space when the pulse width is large compared to the size of the layers but small compared to the large-scale variations of the layering. Then the reflected signals have a particular structure: they...

Frequency Content and Autocorrelation Function of Noisy Periodic Signals

We extract the frequency content of a noisy signal by use of Discrete Fourier Transform. Our analysis overcomes the limitations imposed by incommensurate lattices. After computing the deterministic component, we show the relevance of the method in removing spurious autocorrelations from the signal residuals. Results are presented for a temperature time series.

Inverse problems in atmospheric dispersion with randomly scattered sensors

We consider the problem of monitoring the concentration and dispersion of pollutants in the atmosphere using a collection of randomly scattered sensors. The sensors are capable of only indicating that the concentration has exceeded a randomly selected threshold and providing this information through a transponder-like mechanism to an airborne imaging radar. We use this information together with...

Spectral Analysis of Randomly Sampled Signals