A four-element end-fire microphone array for acoustic measurements in wind tunnels

Author: Noble, S. C.
Published: Jan 1, 1974.
Physical Description: 1 electronic document
Additional Creators: Soderman, P. T.

Online Version

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Summary

A prototype four-element end-fire microphone array was designed and built for evaluation as a directional acoustic receiver for use in large wind tunnels. The microphone signals were digitized, time delayed, summed, and reconverted to analog form in such a way as to create a directional response with the main lobe along the array axis. The measured array directivity agrees with theoretical predictions confirming the circuit design of the electronic control module. The array with 0.15 m (0.5 ft) microphone spacing rejected reverberations and background noise in the Ames 40- by 80-foot wind tunnel by 5 to 12 db for frequencies above 400 Hz.

Other Subject(s)

ELECTRONIC EQUIPMENT

Collection

NASA Technical Reports Server (NTRS) Collection.

Note

Document ID: 19740007800.
Accession ID: 74N15913.
NASA-TM-X-62331.

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