Adaptive windows via Kalman filtering in the spectral domain
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Authors
Adamo, Ronald Carl
Subjects
Signal processing
Kalman filter
Grey-tone displays
Periodgram
Spectral analysis
Kalman filter
Grey-tone displays
Periodgram
Spectral analysis
Advisors
Hippenstiel, Ralph D.
Date of Issue
1991-03
Date
Publisher
Monterey, CA; Naval Postgraduate School
Language
Abstract
Application of classical windows to time series data is a means of enhancing the performance of the periodgram. Use of these classical windows results in the broadening of the spectral mainlobe. A Kalman filter will smooth spectral data by dividing the periodgram of unwindowed time series data into piecewise constant segments, ideally into noise-only and signal-only segments. This allows for a more accurate representation of the mainlobe of the original periodgram. The Kalman filter was modified to alter the filter parameter (b) during filtering to provide maximum smoothing during the noise-only segment and maximum sensitivity in the vicinity of the spectral peak of the periodgram. This modification results in a smoothing of the noise-only portion of the periodgram while leaving the main spectral peak essentially unaltered. A second modification was made to substitute the original raw values of the periodgram for the filter estimates during detected up-transitions while smoothing the noise-only segments in the same manner as the original Kalman filter algorithm. This further enhances the preservation of the mainlobe of the periodgram and lowers the noise floor 1 to 3 dB over the of the original Kalman filter. these processes were further enhanced by stacking the output periodgrgams and displaying them as LOFAR output on the Sun workstation. NCAR graphics grey-toning subroutine is used to generate the LOFAAR displays.
Type
Thesis
Description
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Format
120 p.;28 cm.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.