Accession Number : AD0767641

Title :   Estimation of the Two-Dimensional Spectrum of the Space-Time Noise Field for a Sparse Line Array.

Descriptive Note : Technical rept.,

Corporate Author : NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CONN NEW LONDON LAB

Personal Author(s) : Nuttall,Albert H. ; Montavon,Ernest M. ; Carter,G. Clifford

Report Date : 22 AUG 1973

Pagination or Media Count : 42

Abstract : For a line array immersed in a stationary homogeneous noise field composed of plane waves of differing speeds and angles of arrival, standard beamforming is not useful for estimating the noise spectrum directionality. However, the two-dimensional spectrum of the received noise field enables resolution in temporal-frequency and in spatial-frequency and can thereby indicate the temporal-frequency content and the apparent speed along the line array of plane wave arrivals. The interrelationships and attributes of the space-time correlation, the cross-spectrum, and the two-dimensional spectrum are presented and interpreted via simple examples. A program for estimation of the two-dimensional spectrum for a sparse line array and examples of its use and interpretation are given. (Author)

Descriptors :   (*INFORMATION THEORY, ACOUSTIC SIGNALS), NOISE, CORRELATION TECHNIQUES, POWER SPECTRA, INTEGRAL TRANSFORMS, FOURIER ANALYSIS, INTERPOLATION, COMPUTER PROGRAMS

Subject Categories : Cybernetics
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE