AUTOMATIC PROCESSING OF INFRASONIC DATA,
Abstract
Automatic techniques have been developed for identification of propagational modes contained in infrasonic waves. Digital Fourier analysis applied to sequential time windows resolves the signal in the period (or frequency) and time domain. Computerized mapping of isobaric contour lines in the time-period plane reveals the different modes of propagation. A Wiener-Hopf filter, used in communication theory for filtering noise by minimizing the mean square error with respect to a 'desired spectrum', has here been extended to include mode filtering as well as noise suppression. The undesired normal modes have been treated as event-independent noise, resulting in a digital filter process which extracts a particular mode from the complex infrasonic signal. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1969
- Accession Number
- AD0689182
Entities
People
- Adolph Baker
- B. W. Reinisch
Organizations
- Lowell Technological Institute