1 Introduction, state of the art
2 The INRIM divider
3 Calibration of the divider
3.1 Step response tests
Parameter | TN | ts | β | Tα |
---|---|---|---|---|
Obtained | 70.05 ns | 220 ns | 0.6717% | 70.15 ns |
Recommended | ≤ 15 ns | ≤ 200 ns | ≤ 30 ns |
Parameter | TN | ts | β | Tα |
---|---|---|---|---|
Obtained | 27.25 ns | 161 ns | 0.7431% | 25.71 ns |
Recommended | ≤ 15 ns | ≤ 200 ns | ≤ 30 ns |
3.2 Measurement of the scale factor of the divider
3.3 Calibration uncertainties
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F(≅ 186) is the unknown scale factor of the divider;
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Vcal_acc is the voltage supplied by the calibrator (≅ 1000 V) whose standard uncertainty corresponds to the one-year accuracy specifications of the calibrator;
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Vcal_cal is an additive voltage (≅ 0 V) whose standard uncertainty is obtained from the calibration certificate of the calibrator;
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VDMM_acc is the voltage measured by the DMM (≅ 5 V) whose standard uncertainty corresponds to the one-year accuracy specifications of the DMM;
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VDMM_cal is an additive voltage (≅ 0 V) whose standard uncertainty is obtained from the calibration certificate of the DMM;
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r ≅ 1 is a corrective factor of the voltage ratio measurements whose standard uncertainty is the standard deviation of the mean of the r measurements.
Quantity | Estimate | u(xi) | Typea | ci | ui (F) | νi |
---|---|---|---|---|---|---|
Vcal_acc | ≅ 1000 V | 56.5 mV [24] | B | ≅ 0.2 V─1 | 6.1 × 10─3 | ≅ ∞ |
Vcal_cal | ≅ 0 V | 10 mV | B | ≅ 0.2 V─1 | 1.1 × 10─3 | ≅ ∞ |
VDMM_acc | ≅ 5.36 V | 225 μV [25] | B | ─186.6 V─1 | 2.4 × 10─2 | ≅ ∞ |
VDMM_cal r | ≅ 0 V ≅ 1 | 13 μV 7.4 × 10─17 | B A | ─186.6 V─1 186.6 | 1.4 × 10─3 1.4 × 10─14 | ≅ ∞ 17 |
F (y) | 186.6 | u(F)b | 1.3 × 10─4c | νeff ≅ ∞ | ||
F (y) | 186.6 | U(F)d | 2.7 × 10─4 | k ≅ 1.96 |
Quantity | Estimate | u(xi) | Type | ci | ui (F) | νi |
---|---|---|---|---|---|---|
Vcal_acc | ≅ 1000 V | 0.92 V [22] | B | ≅ 0.2 V−1 | 9.9 × 10─2 | ≅ ∞ |
Vcal_cal | ≅ 0 V | 35 mV | B | ≅ 0.2 V−1 | 3.8 × 10─3 | ≅ ∞ |
VDMM_acc VDMM_cal r | ≅ 5.38 V ≅ 0 V ≅ 1 | 5.5 mV [23] 27 μV 2.4 × 10─6 | B B A | ─186.0 V−1 ─186.0 V−1 186.0 | 5.9 × 10─1 2.9 × 10─3 4.5 × 10─4 | ≅ ∞ ≅ ∞ 17 |
F (y) | 186.0 | u(F)b | 3.2 × 10─3c | νeff = 153 | ||
F (y) | 186.0 | U(F)d | 6.4 × 10─3 | k ≅ 2 |
Component | Type | 1 δ (× 10−3) |
---|---|---|
Calibrator accuracy Calibrator calibration DMM accuracy DMM calibration Measurement noise | B B B B A | 6.1 1.1 24 1.4 negl |
Standard uncertainty (normalized ratio square sum) | 0.14c | |
Expanded uncertainty | 0.27d |
Component | Type | 1 δ (× 10−3) |
---|---|---|
Calibrator accuracy Calibrator calibration DMM accuracy DMM calibration Measurement noise | B B B B A | 99 3.8 590 29 0.45 |
Standard uncertainty | 3.2c | |
Expanded uncertainty | 6.4d |