Development of the calibration procedure of the reference sound source and case study on the uncertainty evaluation

Jae-Gap Suh; Wan-Ho Cho

doi:10.7776/ASK.2024.43.3.344

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2024 Vol.43, Issue 3 Preview Page Next Page

Research Article

Development of the calibration procedure of the reference sound source and case study on the uncertainty evaluation 기준음원의 교정 절차 개발 및 불확도 평가 사례

31 May 2024. pp. 344-350

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Abstract

A Reference Sound Source (RSS) is an important standard device employed in measuring sound power. The specifications of RSS is specified in international standards, and it is classified as a major calibration item in the field of acoustic metrology. Since the output power of RSS is affected by the supply voltage, each country needs to secure its own calibration service system. In this study, a procedure for calibrating a RSS is established based on the reverberant room conditions and uncertainty evaluation is conducted. Basically, the calibration procedure can apply a precision measurement process of acoustic power, and here, the measurement method using the reverberation chamber of ISO 3741 is applied. For this purpose, a measurement system is constructed, measurements are conducted with two types of RSS, and measurement uncertainty is evaluated. Through measurement examples, it is confirmed that the non-uniformity of the sound pressure distribution in the reverberation room and the volume measurement uncertainty contributed significantly to the overall uncertainty. Additionally, the influence of input voltage is experimentally examined to examine the uncertainty contribution that can be reflected in acoustic power measurements.

Keywords

Reference sound source

Sound power

Calibration

Uncertainty evaluation

기준음원은 음향파워 측정에 활용되는 중요한 기준기로, 국제 표준으로 그 사양이 규정되어 있으며, 측정 표준 분야에서 주요 교정 품목으로 분류되고 있다. 이러한 기준음원은 공급 전압에 의하여 그 출력이 영향을 받기 때문에 각국에서 자체적으로 교정 서비스 체계를 확보할 필요가 있다. 본 연구에서는 잔향실 조건에서 기준음원을 교정하는 절차를 수립하고 불확도를 평가하였다. 교정 절차는 기본적으로 음향 파워의 정밀급 측정과정을 적용할 수 있으며, 여기서는 ISO 3741의 잔향실을 활용한 측정 방법을 검토하였다. 이를 위한 측정 시스템을 구성하고 실제 2종의 기준음원에 대하여 측정을 수행하고 측정 불확도를 산출하였다. 측정 예를 통하여 잔향실 내 음압 분포의 불균일성과 체적 측정 불확도가 전체 불확도에 기여가 큰 것을 확인하였다. 추가적으로 입력 전압에 대한 영향을 실험적으로 검토하여 음향 파워 측정에서 반영할 수 있는 불확도 기여량을 검토하였다.

키워드

기준음원

음향파워

교정

불확도 평가

References

ISO 6926:2016, Acoustics - Requirements for the Performance and Calibration of Reference Sound Sources used for the Determination of Sound Power Levels, 2016.

M. Vorländer M., and G. Raabe, "Calibration of reference sound sources," Acustica, 81, 247-263 (1995).

ISO 3741:2010, Acoustics - Determination of Sound Power Levels and Sound Energy Levels of Noise Sources using Sound Pressure - Precision Methods for Reverberation Test Rooms, 2010.

ISO 3745:2012, Acoustics - Determination of Sound Power Levels and Sound Energy Levels of Noise Sources using Sound Pressure - Precision Methods for Anechoic Rooms and Hemi-anechoic Rooms, 2012.

ISO 3382-1:2009, Acoustics - Measurement of room acoustic parameters - Part 1: Performance spaces, 2009.

ISO354:2003, Acoustics - Measurement of Sound Absorption in a Reverberation Room, 2003.

ISO/IEC ISO/IEC Guide 98-3:2008, GUM: 1995, Uncertainty of Measurement - Part 3: Guide to the Expression of Uncertainty in Measurement, 2008.

J.-G. Suh and S.-J. Suh, "Calculation and uncertainty estimation of the volume of reverberation chamber with indeterminate form" (in Korean), J. Acoust. Soc. Kr. 26, 375-380 (2007).

KASTO 19-40419-138, Standard Calibration Procedure of Digital Multimeter, 2019.

BIPM, KCDB, https://www.bipm.org/kcdb/cmc/advanced-search?area=1 (Last viewed May 04 2024).

IEC 61094-4:1995, Measurement Microphones - Part 4: Specifications for Working Standard Microphones, 1995.

Information

Publisher :The Acoustical Society of Korea
Publisher(Ko) :한국음향학회
Journal Title :The Journal of the Acoustical Society of Korea
Journal Title(Ko) :한국음향학회지
Volume : 43
No :3
Pages :344-350
Received Date : 2024-03-25
Accepted Date : 2024-05-07
DOI :https://doi.org/10.7776/ASK.2024.43.3.344

The Journal of the Acoustical Society of KoreaISSN:1225-4428(Print) 2287-3775(Online)한국음향학회

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