1、 IEC TR 61094-10 Edition 1.0 2022-08 TECHNICAL REPORT Electroacoustics Measurement microphones Part 10:Absolute pressure calibration of microphones at low frequencies using calculable pistonphones IEC TR 61094-10:2022-08(en)colourinside THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2022 IEC,Gene
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9、n 19 additional languages.Also known as the International Electrotechnical Vocabulary(IEV)online.IEC TR 61094-10 Edition 1.0 2022-08 TECHNICAL REPORT Electroacoustics Measurement microphones Part 10:Absolute pressure calibration of microphones at low frequencies using calculable pistonphones INTERNA
10、TIONAL ELECTROTECHNICAL COMMISSION ICS 17.140.50 ISBN 978-2-8322-4374-9 Registered trademark of the International Electrotechnical Commission Warning!Make sure that you obtained this publication from an authorized distributor.colourinside 2 IEC TR 61904-10:2022 IEC 2022 CONTENTS FOREWORD.4 1 Scope.6
11、 2 Normative references.6 3 Terms and definitions.6 4 Reference environmental conditions.7 5 Principles of absolute pressure calibration of microphones using a calculable pistonphone.7 5.1 General principle.7 5.2 Basic expressions.7 5.3 Heat conduction correction.9 5.4 Operating frequency range.9 6
12、General characteristics.9 6.1 The pistonphone.9 6.2 Measuring the piston volume velocity.10 6.3 Test signals.10 6.4 Mounting the microphone and pressure-equalizing tube.10 6.5 Measuring the output voltages of the microphones.10 7 Factors influencing the pressure sensitivity.10 7.1 General.10 7.2 Pol
13、arizing voltage.11 7.3 Shield configuration.11 7.4 Dependence on environmental conditions.11 7.4.1 General.11 7.4.2 Static pressure.11 7.4.3 Temperature.11 7.4.4 Humidity.12 7.5 Vibration.12 7.6 Distortion.12 8 Calibration uncertainty components.12 8.1 General.12 8.2 Measurements of microphone outpu
14、t voltage.12 8.3 Piston.12 8.3.1 Frequency.12 8.3.2 Measurement of the volume velocity.12 8.4 Acoustic transfer impedance.13 8.4.1 Cavity properties.13 8.4.2 Physical quantities.13 8.5 Microphone parameters.13 8.5.1 Front cavity.13 8.5.2 Acoustic impedance.13 8.5.3 Polarizing voltage.14 8.6 Uncertai
15、nty on pressure sensitivity level.14 Annex A(informative)Example designs of pistonphones using laser interferometry.16 IEC TR 61904-10:2022 IEC 2022 3 Annex B(informative)Measurement uncertainties.18 B.1 General.18 B.2 Example of a typical uncertainty analysis.18 B.2.1 General.18 B.2.2 Uncertainty b
16、udget.18 B.2.3 Combined and expanded uncertainties.19 Bibliography.20 Figure 1 Equivalent circuit for evaluating the sound pressure over the exposed surface of the diaphragm of the microphone.8 Figure A.1 Schematic cross-section of a laser pistonphone.16 Figure A.2 Example of laser pistonphone.17 Figure A.3 Example of laser pistonphone.17 Table 1 Uncertainty components.14 Table B.1 Example of uncertainty budget at 1 Hz.19 4 IEC TR 61904-10:2022 IEC 2022 INTERNATIONAL ELECTROTECHNICAL COMMISSION
