| 1. |
|
|
| 2. |
- Bergsten, Tobias, et al.
(författare)
-
An active filter for Delta-Sigma modulated Josephson waveforms
- 2014
-
Ingår i: CPEM Digest (Conference on Precision Electromagnetic Measurements). - : Institute of Electrical and Electronics Engineers Inc.. - 9781479952052 ; , s. 518-519
-
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.
|
|
| 3. |
- Bergsten, Tobias, et al.
(författare)
-
An Active Filter for Delta-Sigma-Modulated Josephson Waveforms
- 2015
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 64:6, s. 1559-1563
-
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.
|
|
| 4. |
- Bergsten, Tobias, et al.
(författare)
-
An electrical power reference system Up to 1 MHz
- 2016
-
Ingår i: Conference on Precision Electromagnetic Measurements (CPEM 2016).
-
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.
|
|
| 5. |
- Bergsten, Tobias, et al.
(författare)
-
Determining voltage dependence of the phase response in voltage dividers
- 2012
-
Ingår i: Conference on Precision Electromagnetic Measurements, CPEM 2012. ; , s. 282-283
-
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.
|
|
| 6. |
- Bergsten, Tobias, et al.
(författare)
-
Josephson waveform generation using multilevel Δ-Σ Modulation
- 2012
-
Ingår i: Conference on Precision Electromagnetic Measurements, CPEM 2012. ; , s. 172-173
-
Konferensbidrag (refereegranskat)abstract
- We present a novel method of generating an ac voltage using a programmable Josephson voltage standard. The ac voltage is generated by Δ-Σ (Delta-Sigma) modulation of multiple Josephson levels. Compared with an ac voltage generated by stepwise approximation, the Δ-Σ method reduces the low frequency harmonics of the generated signal. We demonstrate this method by generating a 90 Hz sine wave and measuring the spectrum with a digitizer.
|
|
| 7. |
- Budovsky, Ilya, et al.
(författare)
-
International comparison on ac-dc current transfer standards at frequencies up to 1 MHz
- 2008
-
Ingår i: Digest Conference on Precision Electromagnetic Measurements 2008. ; , s. 24-25
-
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.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Eklund, Gunnar, et al.
(författare)
-
Progress towards an impedance bridge using two programmable Josephson voltage standards
- 2014
-
Ingår i: CPEM Digest (Conference on Precision Electromagnetic Measurements). - : Institute of Electrical and Electronics Engineers Inc.. - 9781479952052 ; , s. 224-225
-
Konferensbidrag (refereegranskat)abstract
- We describe the work towards a setup of a low frequency 'Josephson impedance bridge' based on programmable Josephson voltage standards. Tests of ac voltage synthesis and dc voltage measurements of the two programmable Josephson standards have been performed including a direct Josephson dc voltage comparison.
|
|
