The Spatial Transformation of Sound Fields technique (STSF) involves a planar scanning with one or more transducers across the source under investigation. From the scan data obtained, the near field can be examined in terms of pressure, particle velocity, active intensity and reactive intensity by means of acoustical holography while the more distant fields can be determined by application of Helmholtz' integral equation. A certain stationarity of the source is assumed and correlation, phase and amplitude information is obtained by measuring cross spectra across the scan plane. To calculate a radiation pattern from a source, ideally a full matrix of cross spectra between the measurement points on the scan plane should be measured. However, in cases where the number of independent sources within the bandwidth of interest is small, relative to the number of scan positions, not all elements in the cross spectrum matrix need be measured. The STSF technique makes use of this fact and optimises the measurement procedure. Applications include acoustical studies of engines during research and development and simulation of drive-by tests for complete vehicles.
Vehicle noise investigation using spatial transformation of sound fields
Untersuchung der Kraftfahrzeuggeraeusche durch die raeumliche Transformation der Schallfelder
16th ISATA, 16th Int. Symp. on Automotive Technol. and Automation ; 2 , May ; 551-565
1987
15 Seiten, 11 Bilder, 1 Tabelle, 6 Quellen
Aufsatz (Konferenz)
Englisch
Vehicle noise investigation using spacial transformation of sound fields
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