Accession Number : ADA140196

Title :   A Vector Space Approach to Time-Variant Energy Spectral Analysis,

Corporate Author : ROME AIR DEVELOPMENT CENTER GRIFFISS AFB NY

Personal Author(s) : Roach,J E

PDF Url : ADA140196

Report Date : Dec 1983

Pagination or Media Count : 251

Abstract : When analyzing signals, it is natural and useful to think of them in terms of an energy distribution, which is a functio of frequency, evolving with time. Although traditionally used for spectral analysis, the Fourier Transform is inadequate for describing a time evolving spectrum. There are approaches, with appropriate theoretical justification, that attempt to describe the time-variant spectrum. An investigation of these approaches indicates serious difficulties of interpretation and implementation. A more practical and successful approach is a piecewise Fourier Transform. This in-house report provides the theoretical justification, lacking in the open literatures, for the piecewise approach. Also included is a useful framework for applying weighting windows to time-frequency energy spectral analysis. (Author)

Descriptors :   *Vector spaces, *Spectrum analysis, *Signal processing, *Fourier transformation, Frequency, Discrete fourier transforms, Time, Variations, Computer programs, Weighting functions, Windows

Subject Categories : Statistics and Probability

Distribution Statement : APPROVED FOR PUBLIC RELEASE