Evaluation of the phase error in sound intensity measurement

This paper presents an analysis of phase dependencies occurring in investigations of sound intensity, in particular those of the effect of the phase error of measurement equipment on the value and direction of the intensity vector measured at some point. Two methods of intensity measurement, based o...

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Main Author: Teresa KWIEK-WALASIAK
Format: Article
Language:English
Published: Institute of Fundamental Technological Research Polish Academy of Sciences 2015-07-01
Series:Archives of Acoustics
Online Access:https://acoustics.ippt.pan.pl/index.php/aa/article/view/3134
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author Teresa KWIEK-WALASIAK
author_facet Teresa KWIEK-WALASIAK
author_sort Teresa KWIEK-WALASIAK
collection DOAJ
description This paper presents an analysis of phase dependencies occurring in investigations of sound intensity, in particular those of the effect of the phase error of measurement equipment on the value and direction of the intensity vector measured at some point. Two methods of intensity measurement, based on measurement of the particle velocity from the pressure gradient, were taken into consideration: the direct method (formulae (5), (10), (12), (13)) and the one based on the cross-spectrum of acoustic pressure signals (formulae (6), (23)). The phase error Δφ causes changes in the directional characteristic of the system (formula (28), Fig. 7), changes in the values of intensity, measured with changed order of the measurement channels (formula (30), Fig. 6), the ratio of the values of the real part of the cross-spectrum of the pressure processes from the two microphones to that of its imaginary part (Figs. 9-10), and also in the existence of the imaginary part of their cross-spectrum when the two microphones are affected by the same acoustic field (formula (42), Fig. 8). This paper presents theoretical considerations and specific examples of phase error evaluation in equipment used in investigations (Fig. 1) on the basis of the changes in question, which cause it. The phase error of equipment causes considerable distortion of results, involving changes in the measured values, direction and also the sign of the intensity vector in some cases (see Fig. 11), therefore it is important to interpret it correctly.
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spelling doaj-art-878dd5b9ea7c4d2783fee6d410a17c3d2025-08-20T02:39:15ZengInstitute of Fundamental Technological Research Polish Academy of SciencesArchives of Acoustics0137-50752300-262X2015-07-01101Evaluation of the phase error in sound intensity measurementTeresa KWIEK-WALASIAK0Department of Ergonomy, Adam Mickiewicz UniversityThis paper presents an analysis of phase dependencies occurring in investigations of sound intensity, in particular those of the effect of the phase error of measurement equipment on the value and direction of the intensity vector measured at some point. Two methods of intensity measurement, based on measurement of the particle velocity from the pressure gradient, were taken into consideration: the direct method (formulae (5), (10), (12), (13)) and the one based on the cross-spectrum of acoustic pressure signals (formulae (6), (23)). The phase error Δφ causes changes in the directional characteristic of the system (formula (28), Fig. 7), changes in the values of intensity, measured with changed order of the measurement channels (formula (30), Fig. 6), the ratio of the values of the real part of the cross-spectrum of the pressure processes from the two microphones to that of its imaginary part (Figs. 9-10), and also in the existence of the imaginary part of their cross-spectrum when the two microphones are affected by the same acoustic field (formula (42), Fig. 8). This paper presents theoretical considerations and specific examples of phase error evaluation in equipment used in investigations (Fig. 1) on the basis of the changes in question, which cause it. The phase error of equipment causes considerable distortion of results, involving changes in the measured values, direction and also the sign of the intensity vector in some cases (see Fig. 11), therefore it is important to interpret it correctly.https://acoustics.ippt.pan.pl/index.php/aa/article/view/3134
spellingShingle Teresa KWIEK-WALASIAK
Evaluation of the phase error in sound intensity measurement
Archives of Acoustics
title Evaluation of the phase error in sound intensity measurement
title_full Evaluation of the phase error in sound intensity measurement
title_fullStr Evaluation of the phase error in sound intensity measurement
title_full_unstemmed Evaluation of the phase error in sound intensity measurement
title_short Evaluation of the phase error in sound intensity measurement
title_sort evaluation of the phase error in sound intensity measurement
url https://acoustics.ippt.pan.pl/index.php/aa/article/view/3134
work_keys_str_mv AT teresakwiekwalasiak evaluationofthephaseerrorinsoundintensitymeasurement