Measuring and testing – Vibration – By mechanical waves
Patent
1990-11-14
1992-12-22
Williams, Hezron E.
Measuring and testing
Vibration
By mechanical waves
73602, 73641, G01N 2924
Patent
active
051725975
ABSTRACT:
The detection of sound emitted from a source in a dynamic environment of ambient background noise employs a sufficiently distributed array of sound intensity probes enclosing a sound source is adapted to collect measurements over the same time interval in a non-specific acoustic environment. Each probe in the array is comprised of a pair of mutually spaced microphones generally unmatched in their gain and phase response. A multi-channel fourier spectrum analyzer is used to provide a direct signal processing determination of sound intensity at each probe from pressure measurements taken at each microphone. Their computation is corrected to compensate for gain and phase mismatch between each microphone pair using independently derived probe calibration factors. These correction factors are linearly applied to the sound intensity determination at each probe of the array. Based on the geometry of the probe array and the sound intensity computed at each probe; an approximation of the net flow of emitted sound power through the closed surface of the probe array is made. This closed surface integral approach to determining the net flow of sound power effectively averages out any contribution due to ambient background noise, retaining only the total sound power emitted by the source exclusive of background noise.
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Davis Jr. James C.
Finley Rose M.
General Electric Company
Scanlon Patrick R.
Webb II Paul R.
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