euro-asian cooperation of national metrological ... · out between the dp ndi "systema"...

Metrologia 2011 48 Tech. Suppl. 09002 1/21

Final Report 2011-01-24

ЕВРО -АЗИАТСКОЕ СОТРУДНИЧЕСТВО ГОСУДАРСТВЕННЫХ МЕТРОЛОГИЧЕСКИХ УЧРЕЖДЕНИЙ (KOOMET)

EURO -ASIAN COOPERATION OF NATIONAL METROLOGICAL INSTITUTIONS (COOMET)

State Enterprise “Scientific-Research Institute for Metrology of Measurement and Control Systems” (DP NDI “Systema”)

COMPARISON OF MEASUREMENT STANDARDS OF THE ACOUSTIC PRESSURE IN AIR IN THE LOW FREQUENCY RANGE

COOMET.AUV.A-K2

Project COOMET № 431/UA/08

Pilot laboratory: DP NDI “Systema” (Ukraine) Contact person: Dr V. Chalyy, DP NDI “Systema”, str. Krivonosa, 6, Lviv, UA – 79008, Ukraine Telephone: +38 (032) 239 92 23 Fax: +38 (032) 235 84 49 E-mail: [email protected]

_____________________________________________________________________________

Abstract A bilateral regional comparison of national microphone standards from 2 Hz to 250 Hz was carried out between the DP NDI "Systema" (Ukraine) and the VNIIFTRI (Russia) from July to September 2009. The comparison, COOMET.AUV.A-K2, was based on the pressure calibration of laboratory standard microphones type LSIP. The comparison results have been linked to the established Key Comparison Reference Value (KCRV) of CCAUV.A-K2. The degrees of equivalence, expressed as the deviation from the established KCRV and its expanded uncertainty (k = 2), have been determined, and the comparison result is in agreement with the KCRV within the estimated uncertainties at all employed frequencies.


Contents

1. Background .…………………………….……………………………………….….. 3

2. Participants ……………………..…….…………………….…………………..…… 3

3. Circulated microphones ……………….…..…………..………………………..…... 3

4. Measurements ……………………..….…………………………………………….. 3

5. Reported results …………… .………………………………………………….....… 4

6. Calibration method ………………...…..………………...………...………….….…. 4

7. Microphone parameters …….…………………………………….............................. 5

8. Stability of standards ………………………………………………………………... 6

9. Preliminary analysis …....…….……….………………………….............................. 7

10. Procedure of data estimation …………………………….…………………….…... 10

10.1 Transformed data of UA ................................................................................... 10

10.2 Correction estimate ........................................................................................... 10

11. Linking COOMET.AUV.A-K2 to CCAUV.AUV.A-K2 ……………………………... 11

11.1 Degrees of equivalence ..................................................................................... 11

11.2 Pair degrees of equivalence for participants of the RMO KC and CIPM KC 15

12. Conformation of declared uncertainties .................................................................... 17

13. Conclusion ……………………………………………………………………………. 17

14. References …………………………………………………………………………. 17

15. Appendix A - Reported uncertainty budgets ………………………………………. 18

16. Appendix B - Time table ........................................................................................... 21

17. Appendix C - Contact list .......................................................................................... 21


1. Background

It was agreed during the 5th meeting of the TC 1.2 AUV COOMET which took place in Saint-

Petersburg in May 2008 that a regional key comparison (RMO KС) of national measurement standards

in the low-frequency range could be carried out once the key comparison CCAUV.A-K2 (on pressure

calibration of laboratory standard microphones type LSIP in low-frequency range) was complete. An

RMO KC was hence registered as COOMET.AUV.A-K2 at the Joint Committee of the Regional

Metrology Organizations and the BIPM (JCRB) and in the СООМЕТ database (index 431/UA/08). It

was also agreed that DP NDI “Systema” (Ukraine) would be the pilot laboratory.

This key comparison has been carried out according to the RMO Technical protocol

COOMET.AUV.A-K2 that fulfills the requirements of a key comparison [1].

This report is made according to the Recommendation СООМЕТ R/GM/11:2007 [2] which

corresponds to the international document CIPM Comparison Guidelines [3]. The purpose of this

document is to define the degrees of equivalence between the participants.

2. Participants

The following acoustic laboratories participated in the Comparison: DP NDI "Systema" (Ukraine - UA)

and VNIIFTRI (Russia - RU). The time schedule and the contact list are listed in Appendices B and C.

3. Circulated Microphones

Two LS1P microphones were selected for this comparison. They are Brüel & Kjaer type 4160

microphones, with serial numbers 1843699 and 2302536. These two microphones belong to the DP NDI

"Systema". Each participant received both microphones for calibration.

Large temperature changes, sudden shocks and humidity were avoided during transportation in

order not to cause irreversible changes to the microphones. The microphones were returned to the DP

NDI "Systema" to be tested after calibration in the participant laboratory. This procedure ensured that

the stability of the microphones was satisfactory and so that results from different laboratories could be

compared.

4. Measurements

In this key comparison, only a primary method of calibration in accordance with IEC 61094-2 [4] was

used. The microphones require a polarizing voltage of 200 V. Each laboratory determined the open-

circuit pressure sensitivity level of both microphones at nominal frequencies; 2.00 Hz, 2.50 Hz,

3.15 Hz, 4.00 Hz, 5.00 Hz, 6.30 Hz, 8.00 Hz, 10.00 Hz, 12.50 Hz, 16.00 Hz, 20.00 Hz, 25.00 Hz,

31.50 Hz, 63.00 Hz, 125.00 Hz and 250.00 Hz, using their normal primary calibration method. It was

agreed that the pilot laboratory would not collate any other frequencies reported by the participants.

The use of hydrogen-filled couplers and a grease as a means of sealing the microphones to the

test fixture was avoided. Results were converted to the environmental reference conditions given in

IEC 61094-2.


5. Reported Results

Each laboratory reported its results in the form of the typical report that it would normally issue to a

customer. The covering letter includes the method which was used for the calibration, and the values of

temperature and static pressure coefficients of the microphones used in the calculations. The participant

submitted their calibration results to the pilot laboratory by e-mail at the appointed time (Table 1). The

uncertainty budget was evaluated at a level of one standard uncertainty. The combined uncertainty as

well as the expanded uncertainty is reported (see Appendix A).

Table 1. Reported pressure sensitivities of the microphones type 4160 № 1843699, № 2302536

and associated expanded uncertainties per dB (re 1 V/Pa)

Nominal frequency

/ Hz

№1843699 №2302536 Expanded uncertainties (k = 2)

UA RU UA RU UA RU

2 -26.137 -26.36 -25.774 -26.00 0.18 0.14 2.5 -26.251 -26.39 -25.859 -25.98 0.15 0.09

3.15 -26.393 -26.52 -25.977 -26.04 0.13 0.08 4 -26.515 -26.59 -26.098 -26.14 0.11 0.05 5 -26.631 -26.66 -26.197 -26.22 0.09 0.04

6.3 -26.736 -26.75 -26.294 -26.31 0.08 0.04 8 -26.827 -26.83 -26.362 -26.37 0.07 0.04

10 -26.901 -26.90 -26.427 -26.44 0.07 0.04 12.5 -26.958 -26.96 -26.476 -26.48 0.06 0.04 16 -27.015 -27.02 -26.521 -26.52 0.06 0.04 20 -27.058 -27.06 -26.560 -26.56 0.05 0.04 25 -27.087 -27.09 -26.589 -26.59 0.05 0.04

31.5 -27.114 -27.12 -26.612 -26.62 0.05 0.04 40 -27.139 -27.15 -26.638 -26.65 0.05 0.04 50 -27.146 -27.15 -26.640 -26.65 0.05 0.04 63 -27.174 -27.17 -26.672 -26.68 0.04 0.04 80 -27.188 -27.20 -26.683 -26.70 0.04 0.04 100 -27.203 -27.21 -26.697 -26.71 0.04 0.04 125 -27.216 -27.22 -26.705 -26.72 0.04 0.04 160 -27.223 -27.22 -26.713 -26.72 0.04 0.04 200 -27.232 -27.24 -26.720 -26.73 0.04 0.04 250 -27.237 -27.24 -26.725 -26.74 0.04 0.04

6. Calibration Method

VNIIFTRI:

Open-circuit pressure sensitivity was measured according to the recommendations given in IEC 61094-

2 [4]. The temperature transfer function was calculated following Gerber's approach [5].

The depth of the microphone front cavity was measured using an optical focusing microscope. To

determine the total volume of the microphones, the calibrations in three couplers were performed in the

frequency range from 2 Hz to 250 Hz with subsequent minimization of the deviations in the

microphone sensitivity levels measured in each coupler. The nominal lengths of the couplers were


4.3 mm, 7.5 mm and 10.0 mm. The microphone equivalent volume was then calculated from the total

volume and the measured front cavity depth using the value of the cross-section area of 274.4 mm2

provided by the manufacture of the microphones. Typical values of the microphone resonance

frequency (8200 Hz) and loss factor (1.05) were used in the calculations.

The couplers did not contain any capillary tubes, thus no corresponding corrections were applied.

The calibrations were made at prevailing environment conditions and then corrected to the

reference environment conditions. The static pressure coefficients were calculated according to [6]. The

individual microphone lower limiting frequency was determined using a Brüel & Kjær type 4221

calibrator and a Brüel & Kjær type 2631 carrier system.

DP NDI "Systema":

The open-circuit pressure sensitivity level of the microphones were derived at existing conditions and

results were corrected to the reference environmental conditions as given in IEC 61094-2 [4]. Capillary

tubes of the couplers were blocked therefore no corrections on capillary tubes were applied.

The microphones’ resonance frequency, loss factor and the area of cross-section of the front

cavity were taken as typical values according to the manufacturer’s data. The static pressure coefficient

and temperature coefficient were taken according to [7] (Table 2).

The microphone front cavity depth was measured using an optical focusing microscope.

The values of the equivalent microphone volumes that were used in the calculations were

obtained as follows: ten independent measurements of the transfer impedance were made at each of the

1/3-octave frequencies in a range from 63 Hz up to 250 Hz with UA 1413 and UA 1429 couplers. A

minimal value of a discrepancies sum of the equations system was targeted. Further, a search for any

extreme value was carried out using a computerized numerical method. Values of the microphone

equivalent volumes corresponding to the minimal discrepancy sum were used to calculate the

microphone pressure sensitivity.

7. Microphone Parameters

The microphone parameters, reported by the participants, are presented in the Tables 2 and 3.

Table 2. Microphone parameters

Parameters Microphone № 2302536 Microphone № 1843699

UA RU UA RU

Front cavity depth / mm 1.99 1.98 1.95 1.96

Resonance frequency / Hz 8200 8200 8200 8200

Loss factor 1.05 1.05 1.05 1.05 Static pressure coefficient at 250 Hz / [dB kPa–1] -0.0152 Table 3 -0.0152 Table 3

Temperature coefficient at 250 Hz / [dB K–1]

-0.002 -0.002 -0.002 -0.002

Equivalent volume / mm3 136.0 138.0 127.0 125.0


Table 3. Static pressure coefficient at 250 Hz / dB kPa–1 (VNIIFTRI)

Frequency / Hz Static pressure coefficient at 250 Hz / [dB kPa–1]

2 0.023 2.5 0.000

3.15 -0.002 4 -0.004 5 -0.006

6.3 -0.008 8 -0.010

10 -0.011 12.5 -0.012

16 to 25 -0.013 31.5 to 250 -0.014

8. Stability of Standards

Table 4 - Results on the estimation of the long term stability of the microphones

Frequency / Hz

Microphone 4160 №1843699 Microphone 4160 №2302536 Dates of calibrations

Difference / dB

Dates of calibrations Difference

/ dB July 2009 September 2009 July 2009 September 2009

Level of sensitivity / dB relative 1V/Pa

Level of sensitivity /dB relative 1V/Pa

2 -26.137 -26.144 0.007 -25.774 -25.734 -0.040 2.5 -26.251 -26.279 0.028 -25.859 -25.850 -0.009

3.15 -26.393 -26.414 0.021 -25.977 -25.977 0.000 4 -26.515 -26.538 0.023 -26.098 -26.091 -0.007 5 -26.631 -26.650 0.019 -26.197 -26.191 -0.006

6.3 -26.736 -26.752 0.016 -26.294 -26.281 -0.013 8 -26.827 -26.838 0.011 -26.362 -26.358 -0.004

10 -26.901 -26.912 0.011 -26.427 -26.423 -0.004 12.5 -26.958 -26.973 0.015 -26.476 -26.477 0.001 16 -27.015 -27.023 0.008 -26.521 -26.519 -0.002 20 -27.058 -27.063 0.005 -26.560 -26.556 -0.004 25 -27.087 -27.096 0.009 -26.589 -26.588 -0.001

31.5 -27.114 -27.123 0.009 -26.612 -26.610 -0.002 40 -27.139 -27.144 0.005 -26.638 -26.631 -0.007 50 -27.146 -27.165 0.019 -26.640 -26.654 0.014 63 -27.174 -27.186 0.012 -26.672 -26.669 -0.003 80 -27.188 -27.194 0.006 -26.683 -26.678 -0.005

100 -27.203 -27.212 0.009 -26.697 -26.691 -0.006 125 -27.216 -27.223 0.007 -26.705 -26.699 -0.006 160 -27.223 -27.231 0.008 -26.713 -26.709 -0.004 200 -27.232 -27.236 0.004 -26.720 -26.717 -0.003 250 -27.237 -27.247 0.010 -26.725 -26.724 -0.001


-0.200

-0.150

-0.100

-0.050

0.000

0.050

0.100

0.150

0.200

2 3.15 5 8 12.5 20 31.5 50 80 125 200

Frequency / Hz

Difference / dBExpanded uncertainties

Microphone 1843699

Microphone 2302536

Figure 1. The sensitivity deviation for period from 30 July 2009 to 28 September 2009.

9. Preliminary Analysis

The reported sensitivities of the microphones given as the weighted mean values Mwm are represented

in Figures 2 and 3.

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

2 3.15 5 8 12.5 20 31.5 50 80 125 200

Frequency /Hz

Microphone 1843699 UA

Microphone 1843699 RU

Deviation / dB

Figure 2. Deviation of the results from the weighted mean for B&K 4160 №1843699


-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

2 3.15 5 8 12.5 20 31.5 50 80 125 200

Frequency / Hz

Deviation /dB

Microphone 2302536 UA

Microphone 2302536 RU

Figure 3. Deviation of the results from the weighted mean for B&K 4160 №2302536

The weighted mean deviation was calculated using the formula

wm1 MM ; (1)

where

22

21

22

22

1

1

11wm

UU

U

M

U

M

M

, (see part 4 [2]) (2)

for which

М1, U1 – sensitivity of microphones that was measured by means of the UA standard and the associated

expanded uncertainty;

М2, U2 – sensitivity of microphones that was measured by means of the standard RU and the associated

expanded uncertainty.


UA RU UA RU UA RU UA RU-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 1 2 3 4

Deviation / dB

4 Hz2 Hz 10 Hz 250 Hz

Frequencies / Hz

Figure 4. Deviations and declared uncertainties at frequencies 2 Hz; 4 Hz; 10 Hz and 250 Hz

(microphone №1843699).

UA RU UA RU UA RU UA RU-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 1 2 3 4

Deviation / dB

4 Hz2 Hz 10 Hz 250 Hz

Frequencies / Hz

Figure 5. Deviations and declared uncertainties at frequencies 2 Hz; 4 Hz; 10 Hz and

250 Hz (microphone №2302536)

As can be seen in Figures 4 and 5, the weighted mean values of the deviations of the data

submitted by UA and RU do not exceed the declared uncertainties.


10. Procedure of data estimation

The aim of this regional comparison is to extend the metrological equivalence over the measurement

standard to the national metrology institute (NMI) of Ukraine, DP NDI “Systema”, which did not

participate in the CCAUV.A-K2 comparison.

Evaluation of the comparison data carried out is in accordance with the “C” procedure [2], since the

following conditions are met:

a) the travelling standard (microphones) is stable;

b) the measurement results presented by NMIs are reciprocally independent;

c) the Gaussian distribution is assigned to a measurand in each NMI;

d) the same type of microphones were used as the travelling standard in both comparisons

(CCAUV.A-K2 and COOMET.AUV.A-K2);

e) the technical protocols of CCAUV.A-K2 and COOMET.AUV.A-K2 are identical;

f) one participant of COOMET.AUV.A-K2 (VNIIFTRI (RU)) also participated in CCAUV.A-K2

and is the linking NMI;

g) it is assumed that the measurement uncertainty associated with the results of the linking NMI,

obtained in the CCAUV.A-K2 and COOMET.AUV.A-K2 remains the same.

10.1 Transformed data of UA

Transformed data x ~ are determined according to [2]:

ijjij xx ~~, (3)

where

jx~ , ijx ~ - data of COOMET.AUV.A-K2 participant (see Table 1 for UA) and its transformed data

for all frequencies, respectively.

i, j - № of microphone in CCAUV.A-K2 (i = 1; 2) and COOMET.AUV.A-K2 (j = 3; 4)

respectively (two microphones of the same type were used as travelling standard in both

comparisons).

10.2 Correction estimate

Additive correction - ij [2]:

** ~jiij xx (4)

where *

ix , *~jx - data of the linking NMI (RU – VNIIFTRI) obtained in CCAUV.A-K2 and

COOMET.AUV.A-K2 for microphones i and j, respectively (see Tables 1 and 2 [1]);


11. Linking COOMET.AUV.A-K2 to CCAUV.AUV.A-K2

11.1 Degrees of equivalence

The degree of equivalence of UA was estimated by

1) average deviations:

where

or

where ,~ijx - transformed data (Equations (3) and (4));

refix - reference value of the CCAUV.A-K2.

The determination of deviation d is given in Table 5.

2) uncertainty:

where 2u - uncertainty of additive correction.

S, )~( *xu A - standard deviation (type A standard uncertainty) of the linking NMI

(Appendix A Table A1).

Calculations of the uncertainties for UA are given in Table 6.

m

ijmdd

1

1, m=4

(5)

refijij xxd ,~ , (6)

jijji xxxd ~~~, , (7)

)()()~( duxuuxudu Arefjc22

2222 (8)

)~()( *xuSu A22

22 22 (9)

)(

)(

)(1

1

2

2

mm

dd

du

m

ij

A

(10)


Table 5. Calculation of deviation d and associated uncertainty duA ; noting that the deviation in the KCDB is noted as Di.

Frequency

/ Hz

Sensitivity / dB relative 1V/Pa

Deviation / dB

Associated

standard

uncertainty

/ dB CCAUV.A-K2

COOMET.AUV.A-K2

Estimated

reference values RU UA RU UA

refix *ix *~

jx jx~ d13 d14 d23 d24 d d )(du A

Microphone number*

2142633 2142634 1 2 3 4 3 4

2.0 -26.552 -26.768 -26.636 -26.899 -26.00 -26.36 -25.774 -26.137 0.141 0.139 0.094 0.092 0.116 -0.107 0.014 2.5 -26.655 -26.870 -26.667 -26.936 -25.98 -26.39 -25.859 -26.251 0.105 0.130 0.051 0.076 0.090 -0.039 0.017

3.15 -26.757 -26.952 -26.745 -26.995 -26.04 -26.52 -25.977 -26.393 0.070 0.142 0.015 0.087 0.079 -0.015 0.026 4 -26.858 -27.037 -26.838 -27.055 -26.14 -26.59 -26.098 -26.515 0.059 0.092 0.021 0.054 0.056 0.001 0.015 5 -26.947 -27.107 -26.915 -27.118 -26.22 -26.66 -26.197 -26.631 0.059 0.060 0.016 0.017 0.038 0.011 0.012

6.3 -27.032 -27.172 -27.007 -27.176 -26.31 -26.75 -26.294 -26.736 0.036 0.037 0.007 0.008 0.022 0.011 0.008 8 -27.104 -27.230 -27.081 -27.234 -26.37 -26.83 -26.362 -26.827 0.033 0.028 0.006 0.001 0.017 0.010 0.008

10 -27.166 -27.279 -27.142 -27.281 -26.44 -26.90 -26.427 -26.901 0.032 0.023 0.006 -0.003 0.015 0.011 0.008 12.5 -27.218 -27.319 -27.195 -27.320 -26.48 -26.96 -26.476 -26.958 0.022 0.025 -0.002 0.001 0.012 0.011 0.007 16 -27.264 -27.352 -27.242 -27.357 -26.52 -27.02 -26.521 -27.015 0.023 0.027 -0.004 0.000 0.011 0.009 0.008 20 -27.298 -27.381 -27.277 -27.387 -26.56 -27.06 -26.560 -27.058 0.021 0.021 -0.006 -0.006 0.007 0.008 0.008 25 -27.326 -27.405 -27.306 -27.411 -26.59 -27.09 -26.589 -27.087 0.019 0.021 -0.007 -0.005 0.007 0.007 0.008

31.5 -27.347 -27.422 -27.330 -27.432 -26.62 -27.12 -26.612 -27.114 0.027 0.023 0.000 -0.004 0.012 0.004 0.008 40 -26.65 -27.15 -26.638 -27.139 50 -26.65 -27.15 -26.640 -27.146 63 -27.399 -27.461 -27.383 -27.479 -26.68 -27.17 -26.672 -27.174 0.024 0.015 -0.010 -0.019 0.002 -0.001 0.010 80 -26.70 -27.20 -26.683 -27.188

100 -26.71 -27.21 -26.697 -27.203 125 -27.431 -27.492 -27.417 -27.510 -26.72 -27.22 -26.705 -27.216 0.024 0.013 -0.008 -0.019 0.002 -0.002 0.010 160 -26.72 -27.22 -26.713 -27.223 200 -26.73 -27.24 -26.720 -27.232 250 -27.448 -27.511 -27.438 -27.532 -26.74 -27.24 -26.725 -27.237 0.020 0.014 -0.011 -0.017 0.002 -0.005 0.009 * Number № 1 of microphone corresponds to serial № 2142633, № 2 – to № 2142634, № 3 – to № 2302536, № 4 – to № 1843699.


Table 6. Calculation of the combined and expanded uncertainty for UA.

Frequency

/ Hz

Standard uncertainty / dB Expanded uncertainty

(k = 2) type B type A combined )( refxu )( iju )~(xu )(du A duc U / dB

2.0 0.037 0.025 0.086 0.014 0.101 0.20 2.5 0.031 0.022 0.075 0.017 0.088 0.18

3.15 0.032 0.019 0.057 0.026 0.075 0.15 4 0.021 0.016 0.056 0.015 0.065 0.13 5 0.019 0.013 0.045 0.012 0.054 0.11

6.3 0.014 0.011 0.042 0.008 0.048 0.10 8 0.011 0.009 0.037 0.008 0.041 0.08

10 0.010 0.007 0.037 0.008 0.040 0.08 12.5 0.010 0.006 0.032 0.007 0.035 0.07 16 0.009 0.005 0.032 0.008 0.035 0.07 20 0.008 0.005 0.022 0.008 0.026 0.05 25 0.008 0.004 0.022 0.008 0.025 0.05

31.5 0.007 0.004 0.022 0.008 0.025 0.05 63 0.006 0.004 0.018 0.010 0.022 0.04 125 0.005 0.004 0.018 0.010 0.022 0.04 250 0.005 0.004 0.018 0.009 0.022 0.04

Table 7. Degrees of equivalence given as deviation from the KCRV Di and its expanded

uncertainty Ui (k = 2), expressed in dB as a function of frequency for each laboratory.

Freq. / Hz 2 2.5 3.15 4 5 6.3 8 10 DOE→ Di Ui Di Ui Di Ui Di Ui Di Ui Di Ui Di Ui Di Ui Lab i ↓ / dB BEV 0.01 0.19 0.01 0.16 0.00 0.14 0.00 0.12 -0.01 0.10 -0.01 0.07 -0.01 0.06 -0.01 0.05

DPLA 0.00 0.19 0.01 0.16 -0.01 0.14 -0.01 0.09 -0.01 0.09 0.00 0.08 -0.01 0.07 0.00 0.07 NMIJ 0.02 0.23 0.01 0.18 0.00 0.13 0.00 0.10 0.00 0.09 0.00 0.07 0.00 0.06 0.00 0.05

KRISS -0.01 0.92 -0.01 0.66 -0.02 0.48 -0.03 0.34 -0.03 0.25 -0.03 0.19 -0.03 0.14 -0.03 0.11 NPL 0.17 0.15 0.09 0.14 0.07 0.14 0.04 0.10 0.02 0.09 0.02 0.08 0.01 0.06 0.02 0.06 PTB 0.08 0.21 0.07 0.20 0.06 0.21 0.05 0.12 0.04 0.12 0.03 0.11 0.02 0.07 0.01 0.07 CEM -0.07 0.16 -0.06 0.13 -0.07 0.12 -0.06 0.10 -0.06 0.09 -0.05 0.08 -0.05 0.07 -0.04 0.06 UME -0.02 0.07

VNIIFTRI -0.11 0.13 -0.04 0.10 0.00 0.10 0.00 0.07 0.02 0.07 0.01 0.05 0.01 0.04 0.01 0.03

DP NDI 0.12 0.20 0.09 0.18 0.08 0.15 0.06 0.13 0.04 0.11 0.02 0.10 0.02 0.08 0.02 0.08

Continued Table 7.

Freq. / Hz 12.5 16 20 25 31.5 63 125 250 DOE→ Di Ui Di Ui Di Ui Di Ui Di Ui Di Ui Di Ui Di Ui Lab i ↓ / dB BEV -0.01 0.05 0.00 0.04 0.00 0.03 0.00 0.03 0.00 0.03 0.00 0.03 0.001 0.026 0.001 0.026

DPLA 0.00 0.07 0.00 0.06 0.00 0.05 0.01 0.05 0.01 0.03 0.01 0.03 0.003 0.026 0.002 0.026

NMIJ 0.00 0.04 -0.01 0.04 0.00 0.04 0.00 0.04 0.00 0.04 0.00 0.04 0.004 0.030 0.009 0.030

KRISS -0.03 0.09 -0.02 0.08 -0.02 0.06 -0.01 0.04 -0.01 0.03 -0.01 0.03 -0.010 0.030 -0.005 0.030

NPL 0.02 0.05 0.01 0.05 0.00 0.05 0.01 0.05 0.00 0.05 0.00 0.03 0.008 0.030 0.001 0.030

PTB 0.01 0.07 0.01 0.04 0.01 0.04 0.01 0.04 0.01 0.03 0.01 0.03 0.014 0.030 0.013 0.030

CEM -0.03 0.06 -0.03 0.06 -0.02 0.05 -0.02 0.05 -0.02 0.04 -0.02 0.03 -0.013 0.026 -0.012 0.026

UME -0.01 0.06 -0.01 0.06 -0.01 0.05 -0.01 0.05 -0.01 0.05 -0.01 0.04 -0.008 0.039 -0.007 0.039

VNIIFTRI 0.01 0.03 0.01 0.03 0.01 0.03 0.01 0.03 0.01 0.03 0.00 0.03 0.000 0.030 -0.002 0.030

DP NDI 0.01 0.07 0.01 0.07 0.01 0.05 0.01 0.05 0.01 0.05 0.00 0.04 0.002 0.04 0.002 0.04


-0.150

-0.100

-0.050

0.000

0.050

0.100

0.150

0.200

2 2.5 3.15 4 5 6.3 8 10 12.5 16 20 25 31.5 63 125 250

Frequency / Hz

BEV DPLA NMIJ KRISS NPL PTB CEM UME VNIIFTRI DP NDI “Systema”

Dev

iatio

ns d

i p

er la

bora

tory

in d

B (

re 1

V/P

a)

Figure 6. Deviation id in dB (relatively 1V/Pa) per laboratory and frequency

Laboratory

BEV DPLA NMIJ KRISS NPL PTB CEM VNIIFTRI DP NDI “Systema” -1.000

-0.800

-0.600

-0.400

-0.200

0.000

0.200

0.400

0.600

0.800

1.000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Dev

iatio

n / d

B

Figure 7. Degrees of equivalence: deviation Di and its expanded uncertainty per laboratory at

2 Hz, both expressed in dB (relatively 1V/Pa)


Laboratory

BEV DPLA NMIJ KRISS NPL PTB CEM UME VNIIFTRI DP NDI “Systema” -1.000

-0.800

-0.600

-0.400

-0.200

0.000

0.200

0.400

0.600

0.800

1.000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Dev

iatio

n / d

B

Figure 8. Degrees of equivalence: deviation Di and its uncertainty per laboratory at 10 Hz,

both expressed in dB (relatively 1V/Pa)

11.2 Pair degrees of equivalence for participants of COOMET.AUV.A-K2 and CCAUV.A-K2

11.2.1 Pair (i, j) degree of equivalence for participant of COOMET.AUV.A-K2:

difference:

2112 ddd (9)

uncertainty:

)~()~( 22

12

122 xuxudu (10)

where 21 dd , - deviations UA and RU respectively (see table 5); 21 xuxu ~,~ - uncertainties UA and

RU respectively (see table 1).

11.2.2 Pair degree of equivalence for participant of the COOMET.AUV.A-K2 and CCAUV.A-K2:

difference:

jiij xxd ~ (11)

uncertainty for the case when the participant of CCAUV.A-K2 is not a linking NMI:

)()()~( jiij xuuxudu 22

222 (12)


Table 8. Mutual equivalence at 2 Hz; upper triangle – deviations Dij , lower triangle – associated

expended uncertainties Uij, per dB (relatively 1V/Pa)

NMI BEV DPLA NMIJ KRISS NPL PTB CEM VNIIFTRI DP NDI “Systema” BEV -- 0.01 -0.01 0.02 -0.16 -0.07 0.08 0.12 -0.11

DPLA 0.27 -- -0.02 0.01 -0.17 -0.08 0.07 0.11 -0.12

NMIJ 0.30 0.30 -- 0.03 -0.15 -0.06 0.09 0.13 -0.10

KRISS 0.94 0.94 0.95 -- -0.18 -0.09 0.06 0.10 -0.13

NPL 0.24 0.24 0.27 0.93 -- 0.09 0.24 0.28 0.05

PTB 0.28 0.28 0.31 0.94 0.26 -- 0.15 0.19 -0.04

CEM 0.25 0.25 0.28 0.93 0.22 0.26 -- 0.04 -0.19

VNIIFTRI 0.23 0.23 0.26 0.93 0.20 0.25 0.21 -- -0.23

DP NDI “Systema”

0.28 0.28 0.31 0.94 0.25 0.29 0.26 0.24 --

Table 9. Mutual equivalence at 10 Hz; upper triangle – deviations Dij , lower triangle – associated

expended uncertainties Uij, per dB (relatively 1V/Pa)

NMI BEV DPLA NMIJ KRISS NPL PTB CEM UME VNIIFTRI


BEV -- -0.01 -0.01 0.02 -0.03 -0.02 0.03 0.01 -0.02 -0.03

DPLA 0.09 -- 0.00 0.03 -0.02 -0.01 0.04 0.02 -0.01 -0.02

NMIJ 0.07 0.09 -- 0.03 -0.02 -0.01 0.04 0.02 -0.01 -0.02

KRISS 0.12 0.13 0.12 -- -0.05 -0.04 0.01 -0.01 -0.04 -0.05

NPL 0.08 0.09 0.08 0.13 -- 0.01 0.06 0.04 0.01 0.01

PTB 0.09 0.10 0.09 0.13 0.09 -- 0.05 0.03 0.00 -0.01

CEM 0.08 0.09 0.08 0.13 0.08 0.09 -- -0.02 -0.05 -0.06

UME 0.09 0.10 0.09 0.13 0.09 0.10 0.09 -- -0.03 -0.04

VNIIFTRI 0.06 0.08 0.06 0.11 0.07 0.08 0.07 0.08 -- -0.01


0.10 0.11 0.10 0.14 0.10 0.11 0.10 0.11 0.09 --

Table 10. Mutual equivalence at 250 Hz; upper triangle – deviations Dij , lower triangle –

associated expended uncertainties Uij, per dB (relatively 1V/Pa)

NMI BEV DPLA NMIJ KRISS NPL PTB CEM UME VNIIFTRI


BEV -- -0.012 -0.008 0.006 0.000 -0.012 0.013 0.008 0.003 -0.001

DPLA 0.037 -- -0.007 0.007 0.001 -0.011 0.014 0.009 0.004 0.000

NMIJ 0.040 0.040 -- 0.014 0.008 -0.004 0.021 0.016 0.011 0.007

KRISS 0.040 0.040 0.042 -- -0.006 -0.018 0.007 0.002 -0.003 -0.007

NPL 0.040 0.040 0.042 0.042 -- -0.012 0.013 0.008 0.003 -0.001

PTB 0.040 0.040 0.042 0.042 0.042 -- 0.025 0.020 0.015 0.011

CEM 0.037 0.037 0.040 0.040 0.040 0.040 -- -0.005 -0.010 -0.014

UME 0.047 0.047 0.049 0.049 0.049 0.049 0.047 -- -0.005 -0.009

VNIIFTRI 0.040 0.040 0.042 0.042 0.042 0.042 0.040 0.049 -- -0.004


0.051 0.051 0.053 0.053 0.053 0.053 0.051 0.058 0.053 --


12. Confirmation of declared uncertainties

The declared uncertainties are judged to be confirmed if the following equation is satisfied

)( ii dud 2 .

13. Conclusion

The result of the DP NDI “Systema” laboratory (UA) is in agreement with the KCRV and with the

results of the participants in the CCAUV.A-K2 key comparison, being within the estimated

uncertainties.

14. References

1. Final Technical Report for key Comparison CCAUV.A-K2. BEV-Bundesamt für Eich-und Vermessungvesen (Austria) AUSTRIIA. 16 February 2009. www.bipm.org

2. COOMET R/GM/14:2006 COOMET Recommendation. Guidelines for data evaluation of COOMET key comparison, www.coomet.org

3. Guideline for CIPM key comparisons, www.bipm.org 03.1999 (rev. 10.2003)

4. IEC 61094-2:2008 Measurement microphones - Part 2: Primary method for pressure calibration of laboratory standard microphones by the reciprocity technique

5. Gerber H 1964 Acoustic properties of fluid-filled chambers at infrasonic frequencies in the absence of convection J. Acoust. Soc. Am. 36 1427-34

6. Kosobrodov and Kuznetsov “Static pressure coefficients of laboratory standard microphones in the frequency range 2 – 250 Hz”, 11th Int. Congers Sound and Vibration, 2004.

7. Rasmussen K 2001 The Influence of Environmental Conditions on the Pressure Sensitivity of Measurement Microphones Technical Review Brüel & Kjær n° 1.1-13 (Denmark)


15. Appendix A - Reported Uncertainty Budgets

Uncertainty budget for pressure reciprocity calibration of LS1P microphones (VNIIFTRI) A summary of the uncertainty analysis for pressure reciprocity calibration of microphones type LS1P is given below. 1. Type B uncertainty Bu was calculated using the equation:

,3

1

1

2

N

ii

iB x

x

Mu

where M is the microphone pressure sensitivity level;

ii

xx

M

are components of type B uncertainty given in Table 1;

N is the number of components (N = 13). Each component was assumed to be uniformly distributed. 2. Type A uncertainty Au was estimated as:

,

)1(1

2

mm

yy

u

m

jj

A

where m is the number of measurements (m = 3); jy is the result of the sensitivity level measurement with index j ;

y is the average sensitivity level. 3. The expanded uncertainty U was calculated using the equation:

,)( 2295.0 BA uutU

where

is the number of effective degrees of freedom (see Table Д.1): ;11

2

2

2

A

B

u

um

95.0t is the coverage factor for the level of confidence 0.95 and the degrees of

freedom , calculated as the corresponding Student’s distribution quintile.


Table A1: Uncertainty budget VNIIFTI (RU)

Source Δxi Frequency / Hz

2 2.5 3.15 4 5 6.3 8 10 12.5 16 20 25 31.5 63 125 250

Components of type B uncertainty / 10–3 dB. Symbol: i

i

xxM

Electrical Parameters Electrical transfer impedance 0.01 dB 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 Microphone Equivalent volume 5 mm3 11.6 11.8 11.9 12.0 12.1 12.2 12.3 12.4 12.5 12.6 12.6 12.6 12.6 12.7 12.8 12.9 Resonance frequency 20 Hz 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Loss factor 0.05 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.02 Front cavity depth 0.01 mm 6.32 6.41 6.49 6.56 6.62 6.67 6.72 6.76 6.80 6.83 6.86 6.89 6.91 6.97 7.01 7.03 Additional surface area 4 mm2 3.35 2.98 2.64 2.34 2.08 1.85 1.64 1.46 1.31 1.15 1.03 0.92 0.82 0.58 0.41 0.29 Coupler Length 0.01 mm 3.39 3.40 3.42 3.43 3.44 3.45 3.46 3.47 3.47 3.48 3.48 3.49 3.49 3.50 3.51 3.51 Diameter 0.01 mm 3.04 3.02 3.00 2.98 2.97 2.96 2.94 2.93 2.92 2.92 2.91 2.90 2.90 2.88 2.87 2.86 Environmental Conditions Pressure 20 Pa 0.85 0.84 0.84 0.83 0.83 0.82 0.82 0.82 0.82 0.81 0.81 0.81 0.81 0.80 0.80 0.85 Temperature 2 °C 3.18 2.87 2.58 2.32 2.11 1.91 1.73 1.58 1.45 1.32 1.22 1.12 1.04 0.83 0.70 0.61 Relative humidity 20 %RH 1.20 1.19 1.18 1.18 1.17 1.17 1.16 1.16 1.16 1.15 1.15 1.15 1.15 1.14 1.14 1.14 Corrections to reference environmental conditions

Pressure correction 5*10–4 dB 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 Temperature correction 16*10–4 dB 4.80 4.80 4.80 4.80 4.80 4.80 4.80 4.80 4.80 4.80 4.80 4.80 4.80 4.80 4.80 4.80 Total type B uncertainty. Symbol: Bu 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.4 13.4 13.4 13.4 13.4 13.5 13.5 13.5

Type A uncertainty, 10–3 dB. Symbol: Au

Standard deviation of 3 measurements 25 22 19 16 13 11 9 7 6 5 5 4 4 4 4 4

Effective degrees of freedom. Symbol:

3.28 3.72 4.43 5.71 8.38 12.2 20.4 43.0 71.1 103 177 300 300 303 305 306

Coverage factor for the level of confidence 0.95. Symbol: )(95.0 t

3.03 2.86 2.67 2.48 2.29 2.18 2.08 2.02 1.99 1.98 1.97 1.97 1.97 1.97 1.97 1.97

Expanded uncertainty, 10–3 dB. Symbol: U 86 74 62 52 43 38 34 30 29 29 28 28 28 28 28 28


Table A2: Uncertainty budget of DP NDI "Systema" (UA)

Frequency range: 1) 2Hz to 6.3 Hz ; 2) 10Hz to 16 Hz; 3) 20 Hz to 50 Hz; 4) 63Hz to 250 Hz. Coverage factor is k=2.

No. Input quantity Sign Error limits. ± a Frequency / Hz

2 2.5 3.15 4 5 6.3 8 to 10 12.5 to 16 20 to 50 63 to 250

Components of type B uncertainty / dB × 10—3

1 Electrical transfer impedance (Voltage ratio)

U12 0.07to 0.121) 69 65 60 50 40 38 33 27 15 10 2 U13 0.042) ; 0.023)

3 U23 0.0154) 4 Temperature T 0.2 K 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 5 Static pressure ps 0.27 kPa 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 6 Relative humidity H 6% 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2

7 Condenser capacity Cs 0.1% 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5

8 Frequency f 0.1% 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 9 Coupler length lc 0.003 mm 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

10 Coupler diameter dc 0.012 mm 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 11 Front cavity depth lF 0.05 mm 5 5 5 5 5 5 5 5 5 5 12 Front cavity diameter dF 0.03 mm 3 3 3 3 3 3 3 3 3 3 13 Equivalent volume Ve 5% 12 12 12 12 12 12 12 12 12 12 14 Polarizing voltage Up 0.05 V 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3

15 Resonance frequency f0 1680 Hz 0 0 0 0 0 0 0 0 0 0

16 Loss factor D 0.09 0 0 0 0 0 0 0 0 0 0 17 Static pressure correction δp 0.0014 dB·(kPa)–1 3 3 3 3 3 3 3 3 3 3 18 Temperature correction δt 0.0016 dB·K–1 2 2 2 2 2 2 2 2 2 2

Total standard type B uncertainty uB 70.47 66.56 61.69 52.01 42.49 40.61 35.98 30.57 20.75 17.48

Type A uncertainty / dB × 10—3. Standard type A uncertainty (10 measurements)

uA 50 35 25 20 15 12 10 9 8 5

Combined uncertainty. dB·10–3. uc 86.41 75.20 66.56 55.73 45.06 42.35 37.34 31.87 22.24 18.18

Expanded uncertainty (k = 2). dB·10–3. U 172.82 150.41 133.12 111.45 90.12 84.70 74.69 63.74 44.48 36.36

Reported Expanded uncertainty (k = 2). dB U 0.18 0.15 0.13 0.11 0.09 0.08 0.07 0.06 0.05 0.04


16. Appendix B - Time table

NMI Period of receipt of the microphones

Period for calibration including the transportation back

Note

DP NDI “Systema” - 10.07.2009 – 31.07.2009

VNIIFTRI 3.08.2009 to 09.08.2009 10.08.2009 – 29.08.2009

DP NDI “Systema” 31.08.2009 to 06.09.2009 7.09.2009 – 28.09. 2009

17. Appendix C – Contact list

№ NMI’s Name Address NMI’s

acronym Contact persons

Phone, Fax, E-mail

1 All-Russian Institute of Physical-Technical Radiotechnical Measurements

Mendeleevo RU - 141570 Moscow region, Russia

VNIIFTRI Anatoly Konkov

Phone/ Fax: +7 (495) 744 81 28 E-mail: [email protected]

2 State Enterprise “Scientific-Research Institute for Metrology of Measurement and Control Systems”

str. Krivonosa, 6, UA - 79008, Lviv, Ukraine


Volodymyr Chalyy

Phone.: +38 (032) 239 92 23 Fax: +38 (032) 235 84 49 E-mail: [email protected]

euro-asian cooperation of national metrological ... · out between the dp ndi "systema"...

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