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Ebenhag, Sven-ChristianORCID iD iconorcid.org/0000-0001-7388-4175
Publications (10 of 26) Show all publications
Lindblom, M., Patzauer, M., Vogt, U., Wilbur, S., Safari Yazd, N., Hey Tow, K., . . . Ebenhag, S.-C. (2023). Flexible Liquid-Filled Scintillating Fibers for X-Ray Detection. In: 2023 IEEE SENSORS: . Paper presented at 2023 IEEE SENSORS.29 October 2023 - 01 November 2023. Vienna, Austria.. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Flexible Liquid-Filled Scintillating Fibers for X-Ray Detection
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2023 (English)In: 2023 IEEE SENSORS, Institute of Electrical and Electronics Engineers (IEEE), 2023Conference paper, Published paper (Refereed)
Abstract [en]

We present the design and fabrication of flexible, liquid-filled scintillating fibers for X-ray detection made from silica fibers and silica capillaries. The scintillating fibers were characterized using ultraviolet light exposure and we also performed an experiment demonstrating X-ray detection.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-68522 (URN)10.1109/SENSORS56945.2023.10325072 (DOI)
Conference
2023 IEEE SENSORS.29 October 2023 - 01 November 2023. Vienna, Austria.
Note

This project has received funding from the European Union's Horizon 2020 Research and Innovation Program under Grant Agreement No. 899634.

Available from: 2023-12-13 Created: 2023-12-13 Last updated: 2024-04-03Bibliographically approved
Hedekvist, P. O., Ebenhag, S.-C., Rieck, C., Wallberg, D. & Bergroth, M. (2022). Fiber Optic Time Transfer from UTC(k) to a VLBI Antenna in a Coherent Communication Network. In: 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022 - Proceedings: . Paper presented at 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022, 24 April 2022 through 28 April 2022. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Fiber Optic Time Transfer from UTC(k) to a VLBI Antenna in a Coherent Communication Network
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2022 (English)In: 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2022Conference paper, Published paper (Refereed)
Abstract [en]

The local time scale at Onsala Space Observatory is connected to UTC(SP) through a White Rabbit time transfer system operating on the Swedish University Computer Network SUNET. The time transfer enables a robust synchronization of the VLBI and the IGS stations operating at the observatory and can potentially improve the reliability and availability of traceable time at sufficient accuracy. Several months of data are gathered to evaluate long term events and stability metrics. 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2022
Keywords
fiber, synchronization, time dissemination, WDM, White rabbit, Observatories, Coherent communication, Communications networks, Fiber-optics, Local time, Onsala Space Observatory, Time transfer, Time-scales, Transfer systems, Computer operating systems
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-60159 (URN)10.1109/EFTF/IFCS54560.2022.9850949 (DOI)2-s2.0-85137355028 (Scopus ID)9781665497183 (ISBN)
Conference
2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022, 24 April 2022 through 28 April 2022
Note

Funding details: Horizon 2020 Framework Programme, H2020; Funding details: Horizon 2020; Funding text 1: This work was supported by the TiFOON 18SIB06 Project through the EMPIR Programme co-financed by the Participating States and through the European Union’s Horizon 2020 Research and Innovation Program.; Funding text 2: This work was supported by the TiFOON 18SIB06 Project through the EMPIR Programme co-financed by the Participating States and through the European Union's Horizon 2020 Research and Innovation Program.

Available from: 2022-10-10 Created: 2022-10-10 Last updated: 2023-06-08Bibliographically approved
Rieck, C., Jaldehag, K., Ebenhag, S.-C., Jarlemark, P. & Hedekvist, P. O. (2020). Time and frequency laboratory activities at RISE. In: Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI: . Paper presented at 51st Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI 2020, 21 January 2020 through 24 January 2020 (pp. 169-180). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Time and frequency laboratory activities at RISE
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2020 (English)In: Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI, Institute of Electrical and Electronics Engineers Inc. , 2020, p. 169-180Conference paper, Published paper (Refereed)
Abstract [en]

RISE Research Institutes of Sweden is since 2018 the result of a rebranding of SP Technical Research Institute of Sweden and several other national research facilities and test beds in Sweden. This also comprises most national metrology institute (NMI) activities, including time and frequency that is still located at its Borås facilities in the southwest of Sweden since 1995. UTC(SP) remains the official designation of the Swedish UTC(k) realization. It is realized in a classical master clock and phase stepper setup and is locally distributed to different users and time transfer applications. The most recent local clock ensemble consists of four hydrogen masers and three high performance 5071A Cs standards. UTC(SP) is linked to TAI using TWSTFT and GNSS. The primary link is a combination TWGPPP with current calibration uncertainties of 1.1 ns. The time scale is regularly kept within ±5 ns of UTC. RISE has also established several distributed UTC(SP) copies, with both local backups in Borås and facilities at remote sites linked together by GNSS time transfer. Network time distribution at those sites make UTC(SP) publicly available. Additionally, RISE offers several calibration services for the distribution of UTC-traceable time and frequency signals. Time and frequency related metrological research at RISE is mostly concentrated on further refinement of GNSS and TWSTFT methods, their calibration and the dissemination using those methods. We are also active in research on fiber based optical time and frequency transfer. Outside the metrological responsibilities, many research projects focus on establishing metrological aspects of time and frequency within for instance the automotive and maritime domain.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2020
Keywords
Clocks, Hydrogen masers, Time measurement, Calibration uncertainty, National metrology institutes, Research facilities, Research institutes, Technical research, Time and frequencies, Time and frequency transfers, Time distribution, Calibration
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-44903 (URN)10.33012/2020.17297 (DOI)2-s2.0-85081552388 (Scopus ID)0936406259 (ISBN)
Conference
51st Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI 2020, 21 January 2020 through 24 January 2020
Note

Funding details: National Measurement Institute, NMI; Funding details: VINNOVA; Funding text 1: RISE has inherited the function of the Swedish NMI from SP Technical Research Institute of Sweden in 2018 when the RISE institutes Innventia, Swerea, SP and Swedish ICT merged to create a stronger research and innovation partner for businesses and society. The intention is to make industrial research institutes internationally more competitive and to facilitate continued sustainable growth in Sweden by strengthening competitiveness and renewal in the business community [1]. RISE is appointed as the Swedish NMI by the Ministry of Enterprise and Innovation. The NMI is funded from Vinnova [2], Sweden’s innovation agency and any strategic decisions are made by an advisory board composed of experts from Swedish industry. Vinnova decides the level of NMI funding and also the Swedish level of participation in European funded research of the EMPIR program and its possible successor.; Funding text 2: This report was supported by the Swedish National Metrology Program, program owner Swedish Agency for Innovation Systems (VINNOVA). We acknowledge the work of the BIPM, the CCTF and EURAMET, further the Swedish Post and Telecom Authority (PTS) who finances critical Swedish communication infrastructure and thereby strengthens resiliency in national timing.

Available from: 2020-05-20 Created: 2020-05-20 Last updated: 2023-06-08Bibliographically approved
Ebenhag, S.-C., Hedekvist, P. O., Rieck, C., Bergroth, M., Krehlik, P. & Sliwczynski, L. (2019). Evaluation of Fiber Optic Time and Frequency Distribution System in a Coherent Communication Network. In: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings: . Paper presented at 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Evaluation of Fiber Optic Time and Frequency Distribution System in a Coherent Communication Network
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2019 (English)In: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2019Conference paper, Published paper (Refereed)
Abstract [en]

A fiber-based time transfer between UTC(SP) and the VLBI-station at Onsala Space Observatory has been evaluated. The transfer uses a single wavelength in an active coherent DWDM-network in unidirectional duplex fibers and is routed through Reconfigurable Optical Add-Drop Multiplexers.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
fiber optics, time dissemination, traceable, Coherent communication, DWDM networks, Onsala Space Observatory, Reconfigurable optical add-drop multiplexer, Single wavelength, Time and frequencies, Fibers
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-40617 (URN)10.1109/FCS.2019.8856039 (DOI)2-s2.0-85073779075 (Scopus ID)9781538683057 (ISBN)
Conference
2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019
Note

Funding text 1: This work was supported by 15SIB05-OFTEN, which has received funding from the EMPIR programme co-financed by the Participating States within Euramet and from the European Union's Horizon 2020 research and innovation programme.

Available from: 2019-11-25 Created: 2019-11-25 Last updated: 2023-06-08Bibliographically approved
Ebenhag, S.-C., Hedekvist, P. O., Jarlemark, P. & Sundblad, R. (2019). Redundant Distributed Timescale Traceable to UTC(SP). In: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings: . Paper presented at 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Redundant Distributed Timescale Traceable to UTC(SP)
2019 (English)In: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2019Conference paper, Published paper (Refereed)
Abstract [en]

A variety of commerce needs or requires accurate time, such as air traffic control, bank transactions and computer log file comparisons. Whenever the used time needs to be compared with a timestamp generated by another system, both systems must be traceable to a common reference, such as a local UTC(k) realization. Within this paper a distributed timescale using five nodes across Sweden is presented. The foundation for time keeping at each node is two cesium clocks, which are connected to time analysis equipment and equipment for producing redundant timescales. Both timescales are used and distributed throughout the time node and then prioritized by the local NTP servers, PTP grand masters, and other time distribution services. The timescales are monitored by RISE Research Institute of Sweden to ensure traceability to UTC(SP).To compare the timescales of each location with the other locations, GNSS common view is primarily used with an alternative fiber-based solution as back-up. All available time signals are measured relative to the master timescale, and that data is distributed to the other locations to be used as input in the steering of the local timescales. The NTP servers of the time nodes are directly connected to Internet Exchange points, for central, highly available and fair connectivity to the Internet. 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
holdover, redundant, robust, time dissemination, traceable, Location, Air traffic control
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-40616 (URN)10.1109/FCS.2019.8856058 (DOI)2-s2.0-85073793374 (Scopus ID)9781538683057 (ISBN)
Conference
2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019
Note

Funding text 1: The project was funded by the Swedish Post and Telecom Authority (PTS).

Available from: 2019-11-25 Created: 2019-11-25 Last updated: 2023-06-08Bibliographically approved
Ebenhag, S.-C., Hedekvist, P. O. & Weddig, L. (2018). Measurement and Analysis of Polarization Variations in an Optical Coherent Fiber Communication Network Utilized for Time and Frequency Distribution. In: : . Paper presented at 49th Annual Precise Time and Time Interval Systems and Applications Meeting January 29 - 1, 2018 Hyatt Regency Reston Reston, Virginia, USA (pp. 233-236).
Open this publication in new window or tab >>Measurement and Analysis of Polarization Variations in an Optical Coherent Fiber Communication Network Utilized for Time and Frequency Distribution
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

When fiber optic communication networks are used for ultra-stable timing or frequency transfer, there will always be an influence of polarization variation to some extent. The variations can be induced by e.g. mechanical vibration or electromagnetic effects from adjacent power lines. The output polarization from a 120 km fiber transmission of an ultra-stable optical frequency is analyzed and the requirements of a compensation device are quantified.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-37576 (URN)10.33012/2018.15620 (DOI)2-s2.0-85050771424 (Scopus ID)
Conference
49th Annual Precise Time and Time Interval Systems and Applications Meeting January 29 - 1, 2018 Hyatt Regency Reston Reston, Virginia, USA
Available from: 2019-01-24 Created: 2019-01-24 Last updated: 2023-06-08Bibliographically approved
Ebenhag, S.-C., Hedekvist, P. O., Liström, S. & Bergroth, M. (2017). Time and Frequency Dissemination in an All-optical Coherent Fiber Communication Network. In: : . Paper presented at 48th Annual Precise Time and Time Interval Systems and Applications Meeting January 30 - 2, 2017 Hyatt Regency Monterey Monterey, California, USA (pp. 306-311). Institute of Navigation
Open this publication in new window or tab >>Time and Frequency Dissemination in an All-optical Coherent Fiber Communication Network
2017 (English)Conference paper, Published paper (Refereed)
Abstract [en]

A nationwide fiber optic communication network utilizing state-of-the-art technologies with data modulation both in the polarization and in multi-level amplitude and phase is being deployed in Sweden. The network is operated by the Swedish University computer Network, and connects all universities and several research facilities in the country through redundant connections. Since there is a limited amount of clients connected to the network, each client will be assigned a personal wavelength. With a network that is all-optical through an advanced utilization of dynamically reconfigurable optical add and drop multiplexers, each wavelength can theoretically be connected to any other client within the network, enabling broadcasting on allocated wavelengths. The coherent modulation formats also enables signal recovery through electronic digital signal processing after detection, and no optical dispersion compensation is thereby installed. This new network scheme enables a brand new implementation of frequency and time dissemination in the network. The omission of dispersion compensation fibers enhances the symmetry in duplex fiber pair transmission. These optical add-drop installations allow for future efficient frequency and time signal broadcasting from reference nodes operated by distributors such as SP Technical Research Institute of Sweden to users connected to the network.

Place, publisher, year, edition, pages
Institute of Navigation, 2017
Keywords
Broadcasting, Digital signal processing, Dispersion compensation, Drops, Fibers, Light transmission, Modulation, Signal reconstruction, Dispersion-compensation fibers, Fiber communication networks, Fiber optic communications, Optical dispersion compensation, Redundant connections, Research facilities, State-of-the-art technology, Time and frequency disseminations
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:ri:diva-37577 (URN)10.33012/2017.14975 (DOI)2-s2.0-85047021729 (Scopus ID)
Conference
48th Annual Precise Time and Time Interval Systems and Applications Meeting January 30 - 2, 2017 Hyatt Regency Monterey Monterey, California, USA
Available from: 2019-01-24 Created: 2019-01-24 Last updated: 2023-06-08Bibliographically approved
Ebenhag, S.-C., Zelan, M., Hedekvist, P. O., Karlsson, M. & Josefsson, B. (2016). Coherent optical two-way frequency transfer in a commercial DWDM network. In: Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting: . Paper presented at 47th Annual Precise Time and Time Interval Systems and Applications Meeting (PTTI 2016), 25-28 January, 2016, Monterey, US (pp. 116-120).
Open this publication in new window or tab >>Coherent optical two-way frequency transfer in a commercial DWDM network
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2016 (English)In: Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting, 2016, p. 116-120Conference paper, Published paper (Refereed)
Abstract [en]

An experimental fiber connection for ultra-stable optical frequency transfer is established between SP Technical Research Institute of Sweden in Borås and Chalmers University of Technology in Gothenburg. The distance is approximately 60 km, and the connection is implemented in the Swedish University Computer Network. The sites are connected through an active flexible communication network where each optical channel can be configured with terminal equipment based on the user needs. The network is implemented with unidirectional optical amplifiers and duplex fibers. The signal quality and the stability when sending an optical coherent frequency utilizing a wavelength in a DWDM system fiber pair, is evaluated within this work. The aim of the system is to be ultra-stable which corresponds to a stability of 10-13 for t = 1 s (Overlapping Allan Variance), as well as providing the ability to distribute monitored ultra-stable frequency with a future traceability to UTC (SP) to multiple users within the future network. This paper describes the current status and results from the frequency transfer between SP and Chalmers.

Keywords
Dense wavelength division multiplexing, Fiber amplifiers, Optical communication, Platinum alloys, System stability, Telecommunication networks, Chalmers University of Technology, Coherent frequency, Fiber connections, Flexible communication, Frequency transfer, Stable frequencies, Technical research, Terminal equipment, Optical communication equipment
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-27665 (URN)10.33012/2016.13154 (DOI)2-s2.0-84964987466 (Scopus ID)
Conference
47th Annual Precise Time and Time Interval Systems and Applications Meeting (PTTI 2016), 25-28 January, 2016, Monterey, US
Available from: 2016-12-22 Created: 2016-12-21 Last updated: 2023-06-08Bibliographically approved
Ebenhag, S.-C., Zelan, M., Hedekvist, P. O. & Karlsson, M. (2016). Implementation of an optical fiber frequency distribution via commercial DWDM. In: 2016 IEEE International Frequency Control Symposium (IFCS): . Paper presented at 70th IEEE International Frequency Control Symposium (IFCS 2016), May 9-12, 2016, New Orleans, US. , Article ID 7563586.
Open this publication in new window or tab >>Implementation of an optical fiber frequency distribution via commercial DWDM
2016 (English)In: 2016 IEEE International Frequency Control Symposium (IFCS), 2016, article id 7563586Conference paper, Published paper (Refereed)
Abstract [en]

The rapid development in communication infrastructure over the past decades entails an increasing dependence on time and frequency, as well as its redundant distribution. This places demands not only on already existing distribution methods, but also on the development of new ones to meet future needs. To meet these demands several research groups are working on high performance fiber-based frequency transfer techniques. The best achieved performance so far is the techniques using a single bi-directional fiber connection, with customized bi-directional optical amplifiers [1]. The objective of this project is to develop a method that is compatible with data communication in DWDM-systems, i.e. using the existing infrastructure, as well as to be complementary technique for time and frequency distribution. Even though it is likely to have worse performance than the bi-directional system in terms of frequency stability, it will allow for the impassable obligation to follow the deployed structure of telecom networks. The establishment and early results of the non-stabilized link has been previously presented [2, 3]. The ongoing evaluation and improvement will be aimed at finding relevant performance specifications for a connection using this technique. The work presented here is the most recent results of the frequency transfer and discusses the future plans for the fiber connection, including the added time transfer method. If proven successful, the long-term objective is to establish a distribution network for optical frequency references in Sweden.

Keywords
DWDM, Frequency transfer, Optical fiber, Optical fiber network, Dense wavelength division multiplexing, Fibers, Optical fibers, Bi-directional optical amplifiers, Communication infrastructure, Complementary techniques, Evaluation and improvement, Optical fiber networks, Optical frequency references, Performance specifications, Fiber amplifiers
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-27623 (URN)10.1109/FCS.2016.7563586 (DOI)2-s2.0-84990998418 (Scopus ID)9781509020911 (ISBN)
Conference
70th IEEE International Frequency Control Symposium (IFCS 2016), May 9-12, 2016, New Orleans, US
Note

References: Droste, S., Ozimek, F., Udem, T., Predehl, K., Hansch, T.W., Schnatz, H., Grosche, G., Holzwarth, R., Optical-frequency transfer over a single-span 1840 km fiber link (2013) Physical Review Letters, 111 (11), p. 110801; Ebenhag, S.C., Zelan, M., Hedekvist, P.O., Karlsson, M., Josefsson, B., Two-way coherent frequency transfer in a commercial DWDM communication network in Sweden (2015) Frequency Control Symposium & the European Frequency and Time Forum (FCS), 2015 Joint Conference Ofthe IEEE International, pp. 276-279; Zelan, M., Ebenhag, S.C., Hedekvist, P.O., Karlsson, M., Josefsson, B., Two-way coherent optical frequency transfer using unidirectional amplifiers in parallel fibers (2015) 8th Symposium of Frequency Standards and Metrology, , Oct. 12-16, 2015, Potsdam, D. Also submitted to Journal ofPhysics: Conference Series (JPCS)

Available from: 2016-12-22 Created: 2016-12-21 Last updated: 2023-06-08Bibliographically approved
Löthberg, P., Sundblad, R., Andersson, R., Liström, S. & Ebenhag, S.-C. (2016). Network time protocol from a distributed timescale traceable to UTC. In: Proceedings of the 47th Annual Precise Time and Time Interval Systems and Applications Meeting: . Paper presented at 47th Annual Precise Time and Time Interval Systems and Applications Meeting (PTTI 2016), January 25-28, 2016, Monterey, US (pp. 187-192).
Open this publication in new window or tab >>Network time protocol from a distributed timescale traceable to UTC
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2016 (English)In: Proceedings of the 47th Annual Precise Time and Time Interval Systems and Applications Meeting, 2016, p. 187-192Conference paper, Published paper (Refereed)
Abstract [en]

A nationwide robust distributed time scale and network time and frequency distribution infrastructure is implemented in Sweden. The system has been under evaluation since May 2015 and was started as an active service in December 2015. The six local time scales are traceable to UTC within ± 250 ns and NTP time is distributed using customized high performance servers. All output is externally monitored for independent quality and performance assessment.

Keywords
Active service, Distributed time, Local time, Network time protocol, Performance assessment, Time and frequencies, Time-scales, Platinum alloys
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-27662 (URN)10.33012/2016.13163 (DOI)2-s2.0-84964992785 (Scopus ID)
Conference
47th Annual Precise Time and Time Interval Systems and Applications Meeting (PTTI 2016), January 25-28, 2016, Monterey, US
Available from: 2016-12-22 Created: 2016-12-21 Last updated: 2023-06-08Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-7388-4175

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