JJG 1019-2007 Verification Procedure for Working Standard Microphone (Coupled Cavity Comparison Method) JJG1019-2007 Standard download decompression password: www.bzxz.net
This procedure is applicable to the initial verification, subsequent verification and in-use inspection of WS1 and WS2 working standard microphones that meet the requirements of IC 61094-4:1995.

This specification refers to the following documents:
JJF1001—1998 "General metrological terms and definitions"
JJF1034—2005 "Terms and definitions of acoustic metrology"
JJF1059—1999 "Evaluation and expression of measurement uncertainty"
JJG175—1998 "Testing condenser microphones"
JJG176—2005 "Acoustic calibrator"
JJG449—2001 "Octave and 1/3 octave filters"
GB/T3102.7—1993 "Acoustic quantities and units"
GB/T3947—1996 "Terms and definitions of acoustics"
IEC60942:2003 Electroacoustics-Sound calibrators
IEC61094-2:1992 Measurement microphones Part 2: Primary method for pressure calibration of laboratory standard microphones by the ciprocity technique
IEC61094-3:1995 Measurement microphones Part 3: Primary method for free field calibration of laboratory standard microphones by the ciprocity technique
IEC61094-4:1995 Measurement microphones Part 4: Specifications for working standard microphones
||
tt|| IEC61094-5:2001 Measurement microphones Part 5: Methods for pressure calibration of working standard microphones by comparison
When using this procedure, attention should be paid to using the currently valid versions of the above-mentioned references.
1 Scope (1)
2 References (1)
3 Terms and units of measurement (1)
3.1 Working standard microphone (2)
3.2 Coupler cavity (2)
4 Overview (2)
5 Metrological performance requirements (2)
5.1 Sound pressure sensitivity level (2)
5.2 Frequency response of sound pressure sensitivity level (2)
6 General technical requirements (3)
6.1 Marking and factory calibration data (3)
7 Control of measuring instruments (3)
7.1 Verification conditions (3)
7.2 Verification items (4)
7.3 Verification methods (4)
7.4 Processing of verification results (6)
7.5 Verification cycle (6)
Appendix A Format of the inner pages of the verification certificate and verification result notice (7)
Appendix B Examples of measurement uncertainty assessment (9)

National Metrology Verification Regulation of the People's Republic of China JJG1019---2007
Working Standard Microphones(Coupler Comparisan Method)
2007.02-28 Issued
Implementation on 2007-0528
Issued by the General Administration of Quality Supervision, Inspection and Quarantine JJG 1019—2007
Verification Regulation of Working Standard Microphones (Coupler Comparison Method) JJG1019—2007
This regulation was approved by the General Administration of Quality Supervision, Inspection and Quarantine on February 28, 2007, and came into effect on May 28, 2007.
Responsible unit: National Technical Committee on Acoustic Metrology Drafting unit: National Institute of Metrology, Institute of Applied Acoustics, Shaanxi Normal University
This regulation is entrusted to the National Technical Committee on Acoustic Metrology to be responsible for the interpretation of this regulation Drafters of this regulation:
JJG1019—2007
Zhang Mei'e (National Institute of Metrology) Chen Jianlin (National Institute of Metrology) Wu Shengju (Institute of Applied Acoustics, Shaanxi Normal University) Shuai Zhengping (National Institute of Metrology)
Zheng Xiaoyuan (National Institute of Metrology) Bai Ying (National Institute of Metrology)
Scope·
2. References||t t||3 Terms and measurement units
3.1 Working standard microphone
3.2 Coupler cavity..
Overview·
5 Metrological performance requirements
5.1 Sound pressure sensitivity level
5.2 Frequency response of sound pressure sensitivity level
6 General technical requirements·
6.1 Marking and factory calibration data
7 Control of measuring instruments
7.1 Verification conditions
7.2 Verification items
7.3 Verification methods·
7.4 Processing of verification results·
7.5 Verification cycle·
JJG 1019—2007
Appendix A Format of the inner pages of the verification certificate and the verification result notification Appendix B Examples of the evaluation of measurement uncertainty
(3)
JJG 1019--2007
Verification procedure for working standard microphones (coupler cavity comparison method) This procedure is formulated in accordance with the International Electrotechnical Commission standard IEC61094-4:1995 "Measurement microphones Part 4: Specifications for working standard microphones" and IEC61094-5:2001 "Measurement microphones Part 5: Comparison method for sound pressure calibration of working standard microphones". 1 Scope
This procedure is applicable to the initial verification, subsequent verification and in-use inspection of WS1 and WS2 working standard microphones that meet the IEC61094-4:1995 specifications (WS stands for working standard microphone). Abbreviation of ). 2 References This specification also references the following documents: 1998 "General metrology and definitions" JJF 1001-1998 "General metrology and definitions" JJF 1034 JJF 1059 JJG 175 05 "Acoustic metrology standards" JJG 1762 2005 "Sound calibrator" JJG 449 2001 "Octave and 1/3. band filters GB/T 3102 GB/T 3103 39
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phones by When using this regulation, attention should be paid to the use of the currently valid versions of the above-mentioned references. 3 Terms and measurement units
This regulation adopts the acoustic quantities and units specified in GB/T3102.7--1993. This regulation adopts the relevant terms and definitions specified in JJF1034--2005 and GB/T3947--1996. According to the requirements of this regulation, the following terms and definitions in IEC61094-4:1995 and IEC61094-5:2001 are quoted:
JJG 1019-2007
3.1 Working standard microphone A microphone that can be calibrated by at least one of the following methods: a) the method specified in IEC61094-2:1992 or [EC61094-3:1995; b) comparison with a calibrated laboratory standard microphone; c) using the sound calibrator specified in IEC60942:2003. The working standard microphone shall meet specific requirements in terms of mechanical dimensions and electroacoustic performance, especially the requirements on time stability and correlation with environmental conditions. wwW.bzxz.Net
3.2 Coupler
A device that can form a cavity of specified shape and size after the microphone is installed, providing an acoustic coupling unit between microphones and between microphones and sound sources. Note: A coupling cavity containing a radial sound source that can generate a radially symmetrical sound field between the microphone diaphragms when an external electrical signal is applied is called an active coupling cavity.
4 Overview
A working standard microphone is a microphone with specific requirements for mechanical dimensions and electroacoustic performance (especially in terms of time stability and the influence of environmental conditions). It is generally used for the calibration of sound pressure measurement systems and sound measuring instruments. 5 Metering performance requirements
5.1 Sound pressure sensitivity level
The minimum sound pressure sensitivity level of the working standard microphone at the reference frequency f in the range of 200Hz1kHz is shown in Table 1. f is given by the manufacturer. If there is no specific provision, f is 250.Hz. Table 1 Minimum sound pressure sensitivity level of the working standard microphone Metering performance
Minimum sound pressure sensitivity level (reference sensitivity: 1V/Pa) 5.2 Frequency response of sound pressure sensitivity level
The frequency response tolerance of the sound pressure sensitivity level of the working standard microphone is shown in Table 2. Table 2 Tolerance of frequency response of working standard microphone Frequency/Hz
20～fo~2000
Difference/dB
-40 dB
Frequency/Hz
General Technical Requirements
6.1、Marking and Factory Calibration Data
JJG 1019—2007
Table 2 (Continued)
+2.0,-6.0
Difference/dB
6.1.1 The working standard microphone shall have the following clear and durable markings: 1) Manufacturer’s name or trademark;
2) Product model;
3) Product serial number.
+2.0,6.0
6.1.2 Each working standard microphone shall be accompanied by a separate factory calibration document. The factory calibration data shall include the sound pressure sensitivity level of the working standard microphone, the polarization voltage required for normal operation, the reference frequency, and if corrections for air pressure, temperature and relative humidity are required, the corresponding correction coefficients shall be given. 7 Measuring instrument control
Measuring instrument control includes initial verification, subsequent verification and inspection during use. 7.1 Verification conditions
7.1.1 Metrology standards and main supporting equipment1) Laboratory standard microphone
The laboratory standard microphone is used as the reference microphone during verification. Within the verified frequency range, the measurement uncertainty of its sound pressure sensitivity level should be:
LS1P type: (20 Hz~8 kHz): ≤0.05 dB (=2), 10kHz: ≤0.10 dB (k=2);LS2P type: 20 Hz: ≤0.10 dB (=2), (31.5 Hz~8 kHz): ≤0.05 dB (=2), (16 kHz~20 kHz): ≤0.10 dB ( =2). 2) Preamplifier
Within the verified frequency range, the frequency response is better than ±0.2dB, and the stability during verification is better than ±0.01dB. 3) Measuring amplifier
Within the calibrated frequency range, the frequency response is better than ±0.2dB, and the stability during the calibration period is better than ±0.02dB. 3
4) Bandpass filter
JJG 1019—2007
Within the calibrated frequency range, it meets the requirements of JJG449-2001 for the first-level filter. S) Sine signal generator
Within the calibrated frequency range, the amplitude linearity is better than ±0.1dB, the total harmonic distortion is less than 0.05%, and the amplitude stability during the calibration period is better than ±0.02dB. The frequency indication error should be better than ±0.01%. 6) Active coupling cavity
Produces a radially symmetrical sound field within the calibrated frequency range, and the sound pressure level in the cavity should be no less than 80dB. 7) Digital voltmeter
Within the calibrated frequency range,
±0.05% (DC).
8) Sound calibrator
Meet JJG176-2005 for LS grade or
9) Barometer:
Difference should be better than ±0.5% (AC) and
Under the calibration environment conditions, the maximum allowable error should be better than 0.10) Thermometer,
Under the calibration environment conditions, the maximum allowable error is better than 0.11) Hygrometer
Under the calibration environment conditions, the maximum allowable error is better than 7.1.2 Calibration environment conditions
The calibration environment conditions are:
Temperature: (20-26)℃;
|Relative humidity:
30490)%;
Air pressure: (94~103)kPa;
The signal-to-noise ratio in the coupling cavity should be not less than 40dB7.2 Verification items
The verification items of the working standard microphone are shown in the table%RH
Items for the first verification, subsequent verification and inspection during use
Appearance inspection
Sound pressure sensitivity level
Frequency response of sound pressure sensitivity level
Preliminary verification
Subsequent verification
MErROU
CNNE OW SR
Note: “” indicates items to be inspected, and “_” indicates items not to be inspected. 7.3 Verification method
7.3.1: Initial verification and subsequent verification
7.3.1.1 Appearance inspection
In-use inspection
The working standard microphone to be verified shall have clear markings, including model, serial number, etc. The appearance shall not have mechanical damage4
, and the diaphragm shall be clean and free of pollution and corrosion. JJG 1019---2007
The factory calibration data shall comply with the requirements of 6.1.2. 7.3.1.2 Sound pressure sensitivity level
7.3.1.2.1 The working standard microphone to be verified shall be placed in a laboratory that meets the verification environment conditions at least 4 hours before verification, so that the microphone and the verification environment can reach equilibrium. 7.3.1.2.2 The sound pressure sensitivity level of the working standard microphone shall be verified by the simultaneous comparison method. See Figure 1 for a schematic diagram of the verification device.
Measurement amplifier
Amplifier
Specializer
Band pass filter
Digital voltmeter
Voltmeter
Figure 1 Simultaneous comparison of the accuracy of the micro-level
Level calibration device schematic diagram
1) The calibration device should be preheated for no less than 30 minutes to ensure that the polarization voltage is fully stable. 2) Use a digital voltmeter (DC) to check the shoe voltage of the measurement amplifier and adjust it to the required value. 3) Remove the protective grille of the reference microphone and the working standard microphone under test (if any), and install the corresponding adapter ring if necessary. The size specifications of the reference microphone and the working standard microphone under test should be the same. 4) Connect the calibration device as shown in Figure 1. The reference microphone and the working standard microphone under test should be tightly coupled with the active coupling cavity and kept coaxial with the coupling cavity. When necessary, fix them with the spring holder at an angle. 5) Adjust the preamplifier input sensitivity of the two measuring amplifiers so that they are as close as possible to each other. 6) Select the signal generator frequency fo. If the manufacturer does not specify the reference frequency, select 250Hz. 7) Adjust the signal output so that the actual sound pressure level in the cavity is not less than 80dB and there is an appropriate indication on the measuring amplifier.
8) Record the digital voltmeter reading U on the reference microphone channel and the digital voltmeter reading U2 on the tested working standard microphone channel, and calculate the difference △ between the two channels according to formula (1): U
Ar = 20g
JJG 1019-2007
9 Keep the output of the sinusoidal signal generator and the state of the measuring amplifier unchanged, swap the reference microphone and the tested working standard microphone. Be very careful when swapping to avoid affecting the sound pressure level in the cavity. Repeat step 8) to obtain the difference A2°
10) Calculate the sound pressure sensitivity level of the tested working standard microphone according to formula (2), which should meet the requirements of Table 1. Lpx = Lpref
(A, + △2)(dB)
Where: Lnx is the sound pressure sensitivity level of the working standard microphone under test, dB; Lpref is the sound pressure sensitivity level of the reference microphone, dB; △, and △2 are the differences obtained from the two measurements, dB7.3.1.3 Frequency response of sound pressure sensitivity level The frequency response verification device and verification method of sound pressure sensitivity level are the same as those of sound pressure sensitivity level. (2)
Change the frequency of the sine signal generator at 1/3 octave intervals according to Table 2, and repeat steps 7) to 10) in 7.3.1.2.2 to measure and calculate the sound pressure sensitivity level at each frequency point. Among the sound pressure sensitivity levels measured at each frequency point, the sound pressure sensitivity level at f. is used as a reference. The frequency response of the sound pressure sensitivity level should meet the tolerance requirements specified in Table 2. 7.3.2 Inspection in use
7.3.2.1 Appearance inspection
The method of appearance inspection is the same as that of 7.3.1.1.
7.3.2.2 Sound pressure sensitivity level
Install the working standard microphone to be inspected on the preamplifier and connect it to the measuring amplifier. After the prescribed warm-up time, use the sound calibrator to measure the sound pressure sensitivity level of the working standard microphone to be inspected according to the method specified in 4.1.1 of JG175-1998. It should be within the range specified in Table 1. 7.4 Handling of verification results
A verification certificate shall be issued to the working standard microphone that meets the requirements of this regulation after verification. A verification result notice shall be issued to the working standard microphone that fails the verification. The verification result notice shall indicate the unqualified items and explain the items that cannot be further verified. The format of the inner pages of the verification certificate and verification result notice is shown in Appendix A. 7.5 Verification cycle
The verification cycle of the working standard microphone is 1 year. Appendix A
JJG 1019--2007
Inner page format of the verification certificate and verification result notice A.1Inner page format of the verification certificate
Verification results
1. Appearance inspection:
2. Sound pressure sensitivity level:
3. Frequency response of sound pressure sensitivity level: (reference frequency. -Hz)
Frequency/Hz
Sound pressure sensitivity level
Frequency response/dB
Frequency/Hz
Sound pressure sensitivity level
Frequency response/dB
Frequency/Hz
Sound pressure sensitivity level
Frequency response/dB
Frequency/Hz
Sound pressure sensitivity level
Frequency response/dB
Verification conditions:
Polarization voltage:
Relative humidity:
Total page
Hz, reference sensitivity: 1V/Pa)
Air, pressure:
Verification basis: JJG1019-—2007 Verification procedures for working standard microphones (coupled cavity comparison method)Name of standard device used:
Description:
Verification result notification page format
, Appearance inspection:
2. Sound pressure sensitivity level:
JJG 1019-—2007
Test results
Frequency response of sound pressure sensitivity level: (reference frequency f.Frequency/Hz
Frequency response of sound pressure sensitivity level/dB
Frequency/Hz
Frequency response of sound pressure sensitivity level/dB
Frequency/Hz
Frequency response of sound pressure sensitivity level/B
Frequency/H
Frequency response of sound pressure sensitivity level/d
Explanation: Items that cannot be further inspected if the inspection fails Verification conditions: Polarization voltage: Relative humidity: 1607200 Hz, reference sensitivity: 1V/Pa) Verification basis: JJG1019-2007 Verification procedures for working standard microphones (coupled cavity comparison method) Name of the standard device used: Note: The verification result notice should indicate the items that failed the inspection and explain the items that cannot be further inspected. 8
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