| 1. |
- Andersson, Bengt Olof, et al.
(författare)
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The reference step method for DC voltage at 1 mV and 10 mV
- 2014
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Ingår i: CPEM Digest (Conference on Precision Electromagnetic Measurements). - : Institute of Electrical and Electronics Engineers Inc.. - 9781479952052 ; , s. 520-521
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Konferensbidrag (refereegranskat)abstract
- We have investigated the performance of a method called the Reference Step Method at low voltage levels. The method has been evaluated earlier at voltage levels from 0.1 V to 1 kV with excellent results. The advantages of this method are that it uses commonly available equipment and can be fully automated. We have made comparisons with three other low-voltage methods and the differences show that the uncertainties can be less than 30 μV/V at 1 mV and 3 μV/V at 10 mV, making it possible to use this method to perform automated calibration of calibrators with sufficient accuracy for calibration of high-end instruments.
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| 2. |
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| 3. |
- Bergsten, Tobias, et al.
(författare)
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An active filter for Delta-Sigma modulated Josephson waveforms
- 2014
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Ingår i: CPEM Digest (Conference on Precision Electromagnetic Measurements). - : Institute of Electrical and Electronics Engineers Inc.. - 9781479952052 ; , s. 518-519
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Konferensbidrag (refereegranskat)abstract
- We present an active low pass filter constructed for Delta-Sigma modulated Josephson waveforms. The filter has a fifth order Butterworth characteristic with high input impedance and stable passband performance, including dc. We present results from frequency response, input impedance characteristics, passband ac-dc measurements and spectra of a Delta-Sigma modulated sine wave from a programmable Josephson voltage standard.
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| 4. |
- Bergsten, Tobias, et al.
(författare)
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An Active Filter for Delta-Sigma-Modulated Josephson Waveforms
- 2015
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 64:6, s. 1559-1563
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Tidskriftsartikel (refereegranskat)abstract
- We present the design and electrical characteristics of an active low-pass filter. It will be used in a reference waveform source based on a programmable Josephson voltage standard with multilevel delta-sigma modulation to generate accurate and spectrally pure arbitrary waveforms. The filter has a fifth-order Butterworth characteristic with high input impedance, low distortion, high stopband attenuation, and stable passband performance, including dc.
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| 5. |
- Bergsten, Tobias, et al.
(författare)
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An electrical power reference system Up to 1 MHz
- 2016
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Ingår i: Conference on Precision Electromagnetic Measurements (CPEM 2016).
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Konferensbidrag (refereegranskat)abstract
- We present a reference system for calibration of electrical power at frequencies up to 1 MHz. The system consists of several components and we have developed methods of calibrating the components in order to ensure traceability to the SI units. The reference system is designed for steady state sinusoidal signals and gives a preliminary uncertainty of 50 μW/VA at frequencies up to 1 kHz, and 10 mW/VA at 1 MHz.
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| 6. |
- Bergsten, Tobias, et al.
(författare)
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Determining voltage dependence of the phase response in voltage dividers
- 2012
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Ingår i: Conference on Precision Electromagnetic Measurements, CPEM 2012. ; , s. 282-283
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Konferensbidrag (refereegranskat)abstract
- We have developed methods to characterise voltage dependence of the phase response in voltage dividers. The voltage dependence is a combination of two parts, a linear dependence and a power dependence due to voltage and temperature dependence in capacitors respectively. The standard uncertainty of the phase at 240 V and 100 kHz is estimated to be 20 μrad.
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| 7. |
- Bergsten, Tobias, et al.
(författare)
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Realisation of Absolute Phase and Ac Resistance of Current Shunts by Ratio Measurements
- 2018
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Ingår i: CPEM 2018 - Conference on Precision Electromagnetic Measurements. - 9781538609736
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Konferensbidrag (refereegranskat)abstract
- This article presents a method for realising absolute phase and ac resistance for current shunts using only impedance ratio measurements. The method is based on three geometrically identical current shunts with different resistances, but with the same inductance, capacitance and ac resistance (change of resistance at ac compared to dc), We demonstrate how the inductance, capacitance and ac resistance can be calculated from the complex impedance ratio measurements, thereby realising absolute current shunt impedance. This method simplifies the procedure of current shunt calibration, since the same impedance ratio setup which is used to compare a shunt to a reference shunt, is used to realise the impedance of the starting reference shunt.
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| 8. |
- Bergsten, Tobias, et al.
(författare)
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Realization of Absolute Phase and AC Resistance of Current Shunts by Ratio Measurements
- 2019
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 68:6, s. 2041-2046
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a simplified method for realizing absolute phase and ac resistance for current shunts using only impedance ratio measurements. The method is based on three geometrically identical current shunts with different resistances, but with the same inductance, capacitance, and ac-dc resistance change of resistance at ac compared to dc). We demonstrate how the inductance, capacitance, and ac resistance can be calculated from the complex impedance ratio measurements, therefore realizing absolute current shunt impedance. The method gives competitive uncertainties of around 200 μΩ/Ω for amplitude and 400 μrad for phase at 1 MHz in the 1-Ω range.
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| 9. |
- Budovsky, Ilya, et al.
(författare)
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International comparison on ac-dc current transfer standards at frequencies up to 1 MHz
- 2008
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Ingår i: Digest Conference on Precision Electromagnetic Measurements 2008. ; , s. 24-25
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The paper presents an international comparison of ac-dc current transfer measurements at 10 mA and frequencies up to 1 MHz. The standards of NMIA, PTB and BEV have already been compared. The comparison is currently being extended to involve SP. The results will be presented at the conference.
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| 10. |
- Early, Murray, et al.
(författare)
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A simple build-up method for the DC voltage scale of a source
- 2012
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Ingår i: Proc of Conference on Precision Electromagnetic Measurements, CPEM 2012. ; , s. 498-499
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Konferensbidrag (refereegranskat)abstract
- We report on the performance of a simple method, known as the Reference Step Method, to build up the dc voltage scale of a source. The key advantages of this method are that it relies on equipment that is readily available in most high-level laboratories and can be fully automated. The Type A uncertainties achieved by this approach can be less than 0.1 μV/V. This performance is achieved because of the excellent differential linearity of the DMM used in the method. We are validating the accuracy of the method by directly comparing this approach with more traditional resistive divider techniques.
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