Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502410
D. Calonico, C. Clivati, G. Costanzo, A. Godone, F. Levi, Marco Marchetti, A. Mura, M. Prevedelli, M. Schioppo, G. Tino, M. Zucco, N. Poli
The Italian Institute of Metrology (INRIM), the European Laboratory for NonLinear Spectroscopy (LENS), the Physics and Astronomy Department of the University of Firenze (UNIFI) and the Politecnico of Torino started a project to establish a 650 km optical fiber link that will enable remote frequency comparisons between high accuracy microwave and optical clocks of INRIM and UNIFI-LENS and an absolute measurement of the UNIFI-LENS Sr clock versus INRIM Cesium fountains. We report the overall architecture of the project, the present status of the experiment and the preliminary tests performed on the equipments.
{"title":"Optical frequency link between Torino and Firenze for remote comparison between Yb and Sr optical clocks","authors":"D. Calonico, C. Clivati, G. Costanzo, A. Godone, F. Levi, Marco Marchetti, A. Mura, M. Prevedelli, M. Schioppo, G. Tino, M. Zucco, N. Poli","doi":"10.1109/EFTF.2012.6502410","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502410","url":null,"abstract":"The Italian Institute of Metrology (INRIM), the European Laboratory for NonLinear Spectroscopy (LENS), the Physics and Astronomy Department of the University of Firenze (UNIFI) and the Politecnico of Torino started a project to establish a 650 km optical fiber link that will enable remote frequency comparisons between high accuracy microwave and optical clocks of INRIM and UNIFI-LENS and an absolute measurement of the UNIFI-LENS Sr clock versus INRIM Cesium fountains. We report the overall architecture of the project, the present status of the experiment and the preliminary tests performed on the equipments.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"37 1","pages":"396-399"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79146799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502371
M. Ivan, B. Dulmet, G. Martin, S. Ballandras
This paper presents a new patent-pending structure of BAW resonator built on standard silicon wafer and driven by electrostatic force. Thickness-Extensional (TE) modes are exploited, yielding a fundamental frequency near 10 MHz with a 400µm-thick Si wafer. The device is based on a one-port design featuring a 1µm gap submitted to a superimposition of a DC voltage bias and a lesser-amplitude AC excitation. In contrast with conventional bar and plate MEMS resonators relying on structural resonances, our resonators are designed to use an energy-trapping of the TE waves to optimize the Q factor. The structure essentially consists of a single (100) Silicon plate, p-doped and bonded onto a Corning glass substrate by standard anodic bonding. The thin gap required for the electrostatic excitation is machined in the glass layer by Reactive Ion Etching. Extensive electrical and mechanical characterisations were performed. They match rather well the behavior predicted by the theoretical analysis. A compensation of the large static capacitance is needed to give a better access to the motional parameters. Q factors near 9000 have been observed on the fundamental TE-mode, with a sufficient coupling for frequency source applications. The stabilization of a RF oscillator using the resonators is still under development.
{"title":"New electrostatically-excited single crystal silicon resonator vibrating in a Thickness-Extensional mode","authors":"M. Ivan, B. Dulmet, G. Martin, S. Ballandras","doi":"10.1109/EFTF.2012.6502371","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502371","url":null,"abstract":"This paper presents a new patent-pending structure of BAW resonator built on standard silicon wafer and driven by electrostatic force. Thickness-Extensional (TE) modes are exploited, yielding a fundamental frequency near 10 MHz with a 400µm-thick Si wafer. The device is based on a one-port design featuring a 1µm gap submitted to a superimposition of a DC voltage bias and a lesser-amplitude AC excitation. In contrast with conventional bar and plate MEMS resonators relying on structural resonances, our resonators are designed to use an energy-trapping of the TE waves to optimize the Q factor. The structure essentially consists of a single (100) Silicon plate, p-doped and bonded onto a Corning glass substrate by standard anodic bonding. The thin gap required for the electrostatic excitation is machined in the glass layer by Reactive Ion Etching. Extensive electrical and mechanical characterisations were performed. They match rather well the behavior predicted by the theoretical analysis. A compensation of the large static capacitance is needed to give a better access to the motional parameters. Q factors near 9000 have been observed on the fundamental TE-mode, with a sufficient coupling for frequency source applications. The stabilization of a RF oscillator using the resonators is still under development.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"33 1","pages":"221-226"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86606823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502426
T. Feldmann, Arvind Balu, Cedric Molard, W. Schafer, Dirk Piester
Two-Way Satellite Time and Frequency Transfer (TWSTFT) using geostationary telecommunication satellites has become an important technique for comparing remote timescales. There is a need for periodic calibration of the signal delays along the links which are part of the network for the realization of the International Atomic Time (TAI). In order to minimize the efforts of such TWSTFT calibration campaigns, TimeTech GmbH has assembled a mobile station on a trailer. The trailer contains the usual TWSTFT equipment, including the two-way modem, the up/down converters, filters, and amplifiers, as well as monitoring systems, air conditioner, and weather sensors. The steerable antenna is mounted on top of the trailer. The 1 PPS and 10 MHz signals required as input to the TWSTFT equipment are transferred from inside the timing laboratory by an optical link and two reference generators in a master-slave configuration.
{"title":"State-of-the-art time link calibration with a mobile TWSTFT station","authors":"T. Feldmann, Arvind Balu, Cedric Molard, W. Schafer, Dirk Piester","doi":"10.1109/EFTF.2012.6502426","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502426","url":null,"abstract":"Two-Way Satellite Time and Frequency Transfer (TWSTFT) using geostationary telecommunication satellites has become an important technique for comparing remote timescales. There is a need for periodic calibration of the signal delays along the links which are part of the network for the realization of the International Atomic Time (TAI). In order to minimize the efforts of such TWSTFT calibration campaigns, TimeTech GmbH has assembled a mobile station on a trailer. The trailer contains the usual TWSTFT equipment, including the two-way modem, the up/down converters, filters, and amplifiers, as well as monitoring systems, air conditioner, and weather sensors. The steerable antenna is mounted on top of the trailer. The 1 PPS and 10 MHz signals required as input to the TWSTFT equipment are transferred from inside the timing laboratory by an optical link and two reference generators in a master-slave configuration.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"14 1","pages":"462-468"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87408082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502429
J. Kodet, I. Procházka, J. Blažej, P. Pánek, U. Schreiber, P. Lauber
The first results of a two way time transfer between two timing devices over modest distances with sub-ps precision and a few ps accuracy were the major tasks of this work. The two way time transfer scheme employing a single coaxial cable was applied. Based on our previous results we have designed and constructed a timing device which allows registration of Times of Arrivals of pulses with sub-ps timing resolution, linearity, and stability. The concept of the timing devices enables to carry out time tagging of pulses of interest in parallel to the comparison of the time scales of these timing devices. The two timing devices were located in different laboratories and buildings within one institution. The common clock 5 MHz was referenced to a Cesium clock. The analysis of systematic errors contribution shows that the accuracy of the time transfer well below 10 ps may be achieved. The time transfer was accomplished over distances of the order of hundreds of meters. The main limitation for longer distances is the quality of the coaxial cable used for time transfer together with the amount of radiofrequency interference within the experiment.
{"title":"Two way time transfer with picoseconds precision and accuracy","authors":"J. Kodet, I. Procházka, J. Blažej, P. Pánek, U. Schreiber, P. Lauber","doi":"10.1109/EFTF.2012.6502429","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502429","url":null,"abstract":"The first results of a two way time transfer between two timing devices over modest distances with sub-ps precision and a few ps accuracy were the major tasks of this work. The two way time transfer scheme employing a single coaxial cable was applied. Based on our previous results we have designed and constructed a timing device which allows registration of Times of Arrivals of pulses with sub-ps timing resolution, linearity, and stability. The concept of the timing devices enables to carry out time tagging of pulses of interest in parallel to the comparison of the time scales of these timing devices. The two timing devices were located in different laboratories and buildings within one institution. The common clock 5 MHz was referenced to a Cesium clock. The analysis of systematic errors contribution shows that the accuracy of the time transfer well below 10 ps may be achieved. The time transfer was accomplished over distances of the order of hundreds of meters. The main limitation for longer distances is the quality of the coaxial cable used for time transfer together with the amount of radiofrequency interference within the experiment.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"66 3 1","pages":"483-487"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84686033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502398
P. Guillemot, P. Laurent, J. Achkar, D. Rovera, E. Samain, P. Exertier, S. Leon
The Time Transfer by Laser Link (T2L2) experiment, developed by both CNES and OCA, performs ground to ground time transfer over intercontinental distances. The principle is derived from laser telemetry technology with dedicated space equipment designed to record arrival time of laser pulses at the satellite. Using laser pulses instead of radio frequency signals, T2L2 permits to realize some links between distant clocks with time stability of a few picoseconds and accuracy better than 100 ps.
{"title":"Improvement of comparisons between T2L2 & RF links","authors":"P. Guillemot, P. Laurent, J. Achkar, D. Rovera, E. Samain, P. Exertier, S. Leon","doi":"10.1109/EFTF.2012.6502398","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502398","url":null,"abstract":"The Time Transfer by Laser Link (T2L2) experiment, developed by both CNES and OCA, performs ground to ground time transfer over intercontinental distances. The principle is derived from laser telemetry technology with dedicated space equipment designed to record arrival time of laser pulses at the satellite. Using laser pulses instead of radio frequency signals, T2L2 permits to realize some links between distant clocks with time stability of a few picoseconds and accuracy better than 100 ps.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"144 1","pages":"345-348"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77931051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502342
Y. Ovchinnikov
The first characterization of the distributed cavity phase frequency shift of the NPL Rb fountain frequency standard is reported. It is shown how the symmetric part of the distributed cavity phase shift can be used to set up the vertical angle of the fountain. The estimated uncertainty of the distributed cavity phase frequency shift of 1.25×10−16 reduces the total type B uncertainty of the Rb fountain down to 2.4×10−16.
{"title":"Development of NPL Rb fountain frequency standard","authors":"Y. Ovchinnikov","doi":"10.1109/EFTF.2012.6502342","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502342","url":null,"abstract":"The first characterization of the distributed cavity phase frequency shift of the NPL Rb fountain frequency standard is reported. It is shown how the symmetric part of the distributed cavity phase shift can be used to set up the vertical angle of the fountain. The estimated uncertainty of the distributed cavity phase frequency shift of 1.25×10<sup>−16</sup> reduces the total type B uncertainty of the Rb fountain down to 2.4×10<sup>−16</sup>.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"130 1","pages":"96-100"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84791210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502434
M. Underhill
Square waves have instantaneous transitions between fixed upper and lower levels. The timing of the rising and falling transitions or ‘edges’ may be modulated in time and phase separately and independently. The resulting spectrum sidebands are a combination of the two transition modulations. In general the modulation spectrum is asymmetric with different upper and lower sideband spectra. This paper reports an investigation into why this should be so. New methods of single sideband modulation and demodulation are proposed.
{"title":"Asymmetric spectra of phase modulated transitions of square waves","authors":"M. Underhill","doi":"10.1109/EFTF.2012.6502434","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502434","url":null,"abstract":"Square waves have instantaneous transitions between fixed upper and lower levels. The timing of the rising and falling transitions or ‘edges’ may be modulated in time and phase separately and independently. The resulting spectrum sidebands are a combination of the two transition modulations. In general the modulation spectrum is asymmetric with different upper and lower sideband spectra. This paper reports an investigation into why this should be so. New methods of single sideband modulation and demodulation are proposed.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"42 1","pages":"509-513"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73393683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502420
D. Rabus, G. Martin, É. Carry, S. Ballandras
One strategy in addressing the issue of selectivity in direct detection gas sensors - and specifically when using piezoelectric acoustic transducers - is to use multichannel measurement approaches in which each sensor is functionalized with a different chemical layer and provides different responses when exposed to a given mixture of gasses. Within this context, an 8-channel open loop embedded electronics operating as a transmission-mode radiofrequency network analyzer has been developed. The frequency ranges generated by the synthesizer is 50 to 160 MHz or 200 to 500 MHz. A low noise phase detection scheme was implemented, in addition to magnitude measurement. This instrument is used with Surface Acoustic Wave (SAW) and High-overtone Bulk Acoustic Resonator (HBAR) transducers: in the former case, the open-loop approach allows for an improved measurement dynamics, while in the latter case multiple resonances can be probed sequentially, yielding different acoustic penetration depths in the sensing layer. Demonstration of measurement in liquid phase is provided by characterizing the gravimetric sensitivity of HBARs using copper electrodeposition. Values ranging from 2.2 to 13.1 cm2/g are observed, emphasizing a departure from a perturbative Sauerbrey-like relationship.
{"title":"Eight channel embedded electronic open loop interrogation for multi sensor measurement","authors":"D. Rabus, G. Martin, É. Carry, S. Ballandras","doi":"10.1109/EFTF.2012.6502420","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502420","url":null,"abstract":"One strategy in addressing the issue of selectivity in direct detection gas sensors - and specifically when using piezoelectric acoustic transducers - is to use multichannel measurement approaches in which each sensor is functionalized with a different chemical layer and provides different responses when exposed to a given mixture of gasses. Within this context, an 8-channel open loop embedded electronics operating as a transmission-mode radiofrequency network analyzer has been developed. The frequency ranges generated by the synthesizer is 50 to 160 MHz or 200 to 500 MHz. A low noise phase detection scheme was implemented, in addition to magnitude measurement. This instrument is used with Surface Acoustic Wave (SAW) and High-overtone Bulk Acoustic Resonator (HBAR) transducers: in the former case, the open-loop approach allows for an improved measurement dynamics, while in the latter case multiple resonances can be probed sequentially, yielding different acoustic penetration depths in the sensing layer. Demonstration of measurement in liquid phase is provided by characterizing the gravimetric sensitivity of HBARs using copper electrodeposition. Values ranging from 2.2 to 13.1 cm2/g are observed, emphasizing a departure from a perturbative Sauerbrey-like relationship.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"79 1","pages":"436-442"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81212695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502406
M. Siccardi, M. Abgrall, G. Rovera
When speaking of time measurement often no distinction is made between time and time interval but the difference in accuracy between this two cases can be huge. In this paper we will address some of the aspect related to the accuracy in time-tagging a single or repetitive event.
{"title":"About time measurements","authors":"M. Siccardi, M. Abgrall, G. Rovera","doi":"10.1109/EFTF.2012.6502406","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502406","url":null,"abstract":"When speaking of time measurement often no distinction is made between time and time interval but the difference in accuracy between this two cases can be huge. In this paper we will address some of the aspect related to the accuracy in time-tagging a single or repetitive event.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"1 1","pages":"379-382"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83084114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502407
H. Gong, Shaojie Ni, Weihua Mou, Xiangwei Zhu, Feixue Wang
The short-term frequency stability estimation of GNSS on-board clocks is very important for clock modeling and prediction. Orbit Determination and Time Synchronization (ODTS) method is commonly used to estimate the clock offset, which needs continuous observation by large monitoring ground network and complicate algorithms. COMPASS is on its early stage of construction and has not globally distributed station network for satellites tracking. In this paper, we have analyzed an estimation method based on a single monitoring station observation. Based on this method, a simple method for COMPASS MEO/IGSO on-board clocks estimation using smoothed broadcast ephemeris is presented, and a method for COMPASS GEO on-board clocks estimation using satellite radio ranging (SRR) is also discussed. At the end of this paper, the preliminary estimation results for COMPASS IGSO and GEO on-board clocks by these two methods are presented.
{"title":"Estimation of COMPASS on-board clock short-term stability","authors":"H. Gong, Shaojie Ni, Weihua Mou, Xiangwei Zhu, Feixue Wang","doi":"10.1109/EFTF.2012.6502407","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502407","url":null,"abstract":"The short-term frequency stability estimation of GNSS on-board clocks is very important for clock modeling and prediction. Orbit Determination and Time Synchronization (ODTS) method is commonly used to estimate the clock offset, which needs continuous observation by large monitoring ground network and complicate algorithms. COMPASS is on its early stage of construction and has not globally distributed station network for satellites tracking. In this paper, we have analyzed an estimation method based on a single monitoring station observation. Based on this method, a simple method for COMPASS MEO/IGSO on-board clocks estimation using smoothed broadcast ephemeris is presented, and a method for COMPASS GEO on-board clocks estimation using satellite radio ranging (SRR) is also discussed. At the end of this paper, the preliminary estimation results for COMPASS IGSO and GEO on-board clocks by these two methods are presented.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"345 1","pages":"383-386"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78078716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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