Primary calibration of measurement microphones in the world: state of art

Milhomem, T A B; Soares, Zemar Martins Defilippo

doi:10.1088/1742-6596/733/1/012054

Cited by 2 publications

(2 citation statements)

References 2 publications

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“…We aimed to determine the potential of the proposed method for dynamic pressure measurement. If successful, using this method, we could establish the traceability of BP devices through calibration according to acoustic standards such as the primary method for pressure calibration of laboratory standard microphones by the reciprocity technique (IEC 61094-2:2009/AMD1:2022) [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Sphygmomanometer Dynamic Pressure Measurement Using a Condenser Microphone

Tomazini,

Geršak,

Beguš

2023

Sensors

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There is a worldwide need to improve blood pressure (BP) measurement error in order to correctly diagnose hypertension. Cardiovascular diseases cause 17.9 million deaths annually and are a substantial monetary strain on healthcare. The current measurement uncertainty of 3 mmHg should be improved upon. Dynamic pressure measurement standards are lacking or non-existing. In this study we propose a novel method of measuring air pressure inside the sphygmomanometer tubing during BP measurement using a condenser microphone. We designed, built, and tested a system that uses a radiofrequency (RF) modulation method to convert changes in capacitance of a condenser microphone into pressure signals. We tested the RF microphone with a low-frequency (LF) sound source, BP simulator and using a piezoresistive pressure sensor as a reference. Necessary tests were conducted to assess the uncertainty budget of the system. The RF microphone prototype has a working frequency range from 0.5 Hz to 280 Hz in the pressure range from 0 to 300 mmHg. The total expanded uncertainty (k = 2, p = 95.5%) of the RF microphone was 4.32 mmHg. The proposed method could establish traceability of BP measuring devices to acoustic standards described in IEC 61094-2 and could also be used in forming dynamic BP standards.

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Section: Introductionmentioning

confidence: 99%

Sphygmomanometer Dynamic Pressure Measurement Using a Condenser Microphone

Tomazini,

Geršak,

Beguš

2023

Sensors

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“…There are many methods that can be used to calibrate acoustic transducers at infrasonic frequencies. [9][10][11][12] At present, the phase response of acoustic transducers are commonly calibrated using in-situ or calibrator methods to get their phase consistency, [13][14][15][16] while the primary calibration (mainly includes the reciprocity technique and pistonphone), [17][18][19] by which the acoustic transducer is calibrated with reference to non-acoustic standards and with the highest possible precision, is few studied. R. Jackett et al have determined the phase sensitivity uncertainty of microphone based on the reciprocity technique, and found that the low frequency uncertainty due to leakage in microphone cannot be ignored.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study on the phase sensitivity of condenser type acoustic transducers at low frequencies

Liu

Zhang

et al. 2021

Journal of Low Frequency Noise, Vibration and Active Control

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The phase sensitivity of the condenser type acoustic transducers at low frequencies is crucial for locating large-scale natural and manmade activities, but is now commonly calibrated based on comparison methods. Although the primary method, which traces its sensitivity back to the international standard unit is few studied. Recently, the explicit sensitivity models of the condenser type acoustic transducers based on the laser-pistonphone technique are built, and can be used to study the phase responses of acoustic transducers at infrasonic frequencies. So that, in this paper, the phase sensitivities of acoustic transducers when its rear vent connected to the calibrating sound field or outside atmosphere are studied in detail. Secondly, time domain analysis of generated sound pressures by displacement excitation are derived to reveal the mechanism of phase variation. Calculations show two distinct sensitivities with 90° phase lead and −10° phase lag limits for vent in field and vent out field calibrations, which are dominated by the pressure leakage and heat conduction effects at infrasonic frequencies.

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Primary calibration of measurement microphones in the world: state of art

Cited by 2 publications

References 2 publications

Sphygmomanometer Dynamic Pressure Measurement Using a Condenser Microphone

Sphygmomanometer Dynamic Pressure Measurement Using a Condenser Microphone

Theoretical study on the phase sensitivity of condenser type acoustic transducers at low frequencies

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