1、 IEC 61094-2Edition 2.0 2009-02INTERNATIONAL STANDARD NORME INTERNATIONALEElectroacoustics Measurement microphones Part 2: Primary method for pressure calibration of laboratory standard microphones by the reciprocity technique Electroacoustique Microphones de mesure Partie 2: Mthode primaire pour lt
2、alonnage en pression des microphones talons de laboratoire par la mthode de rciprocit IEC61094-2:2009 THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2009 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
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16、r des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du Service clients ou contactez-nous: Email: csciec.ch Tl.: +41 22 919 02 11 Fax: +41 22 919 03 00 IEC 61094-2Edition 2.0 2009-02INTERNATIONAL STANDARD NORME INTERNATIONALEElectroacoustics Measurement microphones
17、Part 2: Primary method for pressure calibration of laboratory standard microphones by the reciprocity technique Electroacoustique Microphones de mesure Partie 2: Mthode primaire pour ltalonnage en pression des microphones talons de laboratoire par la mthode de rciprocit INTERNATIONAL ELECTROTECHNICA
18、L COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE XICS 17.140.50 PRICE CODECODE PRIXISBN 2-8318-1030-4 Registered trademark of the International Electrotechnical Commission Marque dpose de la Commission Electrotechnique Internationale 2 61094-2 IEC:2009 CONTENTS FOREWORD.4 1 Scope.6 2 Normativ
19、e references .6 3 Terms and definitions .6 4 Reference environmental conditions .7 5 Principles of pressure calibration by reciprocity 7 5.1 General principles .7 5.1.1 General .7 5.1.2 General principles using three microphones 7 5.1.3 General principles using two microphones and an auxiliary sound
20、 source .7 5.2 Basic expressions .8 5.3 Insert voltage technique 9 5.4 Evaluation of the acoustic transfer impedance.9 5.5 Heat-conduction correction11 5.6 Capillary tube correction11 5.7 Final expressions for the pressure sensitivity 12 5.7.1 Method using three microphones .12 5.7.2 Method using tw
21、o microphones and an auxiliary sound source 12 6 Factors influencing the pressure sensitivity of microphones13 6.1 General .13 6.2 Polarizing voltage13 6.3 Ground-shield reference configuration.13 6.4 Pressure distribution over the diaphragm 13 6.5 Dependence on environmental conditions .14 6.5.1 St
22、atic pressure 14 6.5.2 Temperature14 6.5.3 Humidity 14 6.5.4 Transformation to reference environmental conditions .15 7 Calibration uncertainty components15 7.1 General .15 7.2 Electrical transfer impedance 15 7.3 Acoustic transfer impedance .15 7.3.1 General .15 7.3.2 Coupler properties.15 7.3.3 Mi
23、crophone parameters .16 7.4 Imperfection of theory17 7.5 Uncertainty on pressure sensitivity level18 Annex A (normative) Heat conduction and viscous losses in a closed cavity 20 Annex B (normative) Acoustic impedance of a capillary tube23 Annex C (informative) Examples of cylindrical couplers for ca
24、libration of microphones 26 Annex D (informative) Environmental influence on the sensitivity of microphones 31 Annex E (informative) Methods for determining microphone parameters 34 Annex F (informative) Physical properties of humid air.37 61094-2 IEC:2009 3 Figure 1 Equivalent circuit for evaluatin
25、g the acoustic transfer impedance Za,12.9 Figure 2 Equivalent circuit for evaluating Za,12when coupler dimensions are small compared with wavelength10 Figure 3 Equivalent circuit for evaluating Za,12 when plane wave transmission in the coupler can be assumed .10 Figure C.1 Mechanical configuration o
26、f plane-wave couplers .27 Figure C.2 Mechanical configuration of large-volume couplers.29 Figure D.1 Examples of static pressure coefficient of LS1P and LS2P microphones relative to the low-frequency value as a function of relative frequency f/fo32 Figure D.2 General frequency dependence of that par
27、t of the temperature coefficient for LS1P and LS2P microphones caused by the variation in the impedance of the enclosed air 33 Table 1 Uncertainty components19 Table A.1 Values for EV.21 Table B.1 Real part of Za,Cin gigapascal-seconds per cubic metre (GPas/m3)24 Table B.2 Imaginary part of Za,Cin g
28、igapascal-seconds per cubic metre (GPas/m3)25 Table C.1 Nominal dimensions for plane-wave couplers.28 Table C.2 Nominal dimensions and tolerances for large-volume couplers 29 Table C.3 Experimentally determined wave-motion corrections for the air-filled large-volume coupler used with type LS1P micro
29、phones30 Table F.1 Calculated values of the quantities in Clauses F.1 to F.5 for two sets of environmental conditions 40 Table F.2 Coefficients used in the equations for humid air properties.41 4 61094-2 IEC:2009 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ ELECTROACOUSTICS MEASUREMENT MICROPHONES Pa
30、rt 2: Primary method for pressure calibration of laboratory standard microphones by the reciprocity technique FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees).
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40、lity that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61094-2 has been prepared by IEC technical committee 29: Electroacoustics. This second edition cance
41、ls and replaces the first edition published in 1992. This second edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: an update of Clause 6 to fulfil the requirements of ISO/IEC Guide 98-3; an improvement of
42、 the heat conduction theory in Annex A; a revision of Annex F: Physical properties of humid air. 61094-2 IEC:2009 5 The text of this standard is based on the following documents: FDIS Report on voting 29/671/FDIS 29/676/RVD Full information on the voting for the approval of this standard can be foun
43、d in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all parts of the IEC 61094 series, published under the general title Electroacoustics Measurement microphones, can be found on the IEC website. The c
44、ommittee has decided that the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a
45、revised edition, or amended. 6 61094-2 IEC:2009 ELECTROACOUSTICS MEASUREMENT MICROPHONES Part 2: Primary method for pressure calibration of laboratory standard microphones by the reciprocity technique 1 Scope This part of International Standard IEC 61094 is applicable to laboratory standard micropho
46、nes meeting the requirements of IEC 61094-1 and other types of condenser microphone having the same mechanical dimensions; specifies a primary method of determining the complex pressure sensitivity so as to establish a reproducible and accurate basis for the measurement of sound pressure. All quanti
47、ties are expressed in SI units. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) app
48、lies. IEC 61094-1:2000, Measurement microphones Part 1: Specifications for laboratory standard microphones ISO/IEC Guide 98-3, Uncertainty of measurement Part 3: Guide to the expression of uncertainty in measurement (GUM:1995)13 Terms and definitions For the purposes of this document, the terms and
49、definitions given in IEC 61094-1 and ISO/IEC Guide 98-3 as well as the following apply. 3.1 reciprocal microphone linear passive microphone for which the open circuit reverse and forward transfer impedances are equal in magnitude 3.2 phase angle of pressure sensitivity of a microphone for a given frequency, the phase angle between the open-circuit voltage and
