Abstract

This thesis describes the phase and amplitude correction of 12.7 mm diameter, Type-1 microphones for three frequency bands, including within the infrasound regime, and its application to acoustic measurements. Previous data stem from acoustic intensity measurements using two-dimensional, four-microphone probes, which emphasized the requirement of having the acoustic phase and amplitude difference be much greater than the interchannel mismatch. Although correcting the amplitude/phase is well-known, obtaining the necessary transfer functions in the infrasound regime is challenging because (1) signal-to-noise ratios are often poor, (2) long measurement times are required for averaging, and (3) microphone responses vary significantly across these low frequencies. In this paper, a convenient infrasound source previously studied for infrasound adverse effects on humans is intended for performing a relative calibration. This work also seeks to elaborate recommendations for probe spacing, averages or length recordings, and instrument mismatch. The last two chapters show the PAGE method application in infrasonic sources. Those chapters have the intensity measurements using free-field microphones with larger separation distances than commercial intensity probes but compact compared to state of the art in infrasonic arrays.

Degree

MS

College and Department

Physics and Astronomy

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2021-07-28

Document Type

Thesis

Handle

http://hdl.lib.byu.edu/1877/etd11829

Keywords

infrasound, infrasound acoustic intensity, acoustic outdoor sources, rocket analysis, balloon burner, microphone calibration, equal excitation, relative calibration

Language

english

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