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Extreme Low Frequency Acoustic Measurement SystemThe present invention is an extremely low frequency (ELF) microphone and acoustic measurement system capable of infrasound detection in a portable and easily deployable form factor. In one embodiment of the invention, an extremely low frequency electret microphone comprises a membrane, a backplate, and a backchamber. The backchamber is sealed to allow substantially no air exchange between the backchamber and outside the microphone. Compliance of the membrane may be less than ambient air compliance. The backplate may define a plurality of holes and a slot may be defined between an outer diameter of the backplate and an inner wall of the microphone. The locations and sizes of the holes, the size of the slot, and the volume of the backchamber may be selected such that membrane motion is substantially critically damped.
Document ID
20170002891
Acquisition Source
Headquarters
Document Type
Other - Patent
Authors
Shams, Qamar A.
Zuckerwar, Allan J.
Date Acquired
April 3, 2017
Publication Date
March 7, 2017
Subject Category
Acoustics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Patent
US-Patent-9,591,417
Patent Application
US-Patent-Appl-SN-13/771,735
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