Accession Number:

AD0689182

Title:

AUTOMATIC PROCESSING OF INFRASONIC DATA,

Descriptive Note:

Corporate Author:

LOWELL TECHNOLOGICAL INST RESEARCH FOUNDATION MASS

Personal Author(s):

Report Date:

1969-02-01

Pagination or Media Count:

55.0

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

Subject Categories:

  • Atmospheric Physics
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE