Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502376
A. Dobrogowski, M. Kasznia
In this paper the methods enabling real-time assessment of dynamic Allan deviation and dynamic time deviation are presented. The idea of real-time analysis of timing signals using dynamic approach is described first. Then the algorithms of real-time computation of dynamic parameters are presented. The results of experimental tests of the methods proposed for different conditions are presented and discussed.
{"title":"Real-time assessment of dynamic Allan deviation and dynamic time deviation","authors":"A. Dobrogowski, M. Kasznia","doi":"10.1109/EFTF.2012.6502376","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502376","url":null,"abstract":"In this paper the methods enabling real-time assessment of dynamic Allan deviation and dynamic time deviation are presented. The idea of real-time analysis of timing signals using dynamic approach is described first. Then the algorithms of real-time computation of dynamic parameters are presented. The results of experimental tests of the methods proposed for different conditions are presented and discussed.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"16 1","pages":"247-252"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81366101","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.2012.6502333
V. Giordano, M. Mrad, J. Masson, P. Bourgeois, Y. Kersalé, S. Grop, B. Dubois
State-of-the-art microwave ultra-stable oscillators are currently based on sapphire resonator operated in whispering gallery modes in the range 5 – 12 GHz. Indeed the best near carrier phase noise is achieved with commercial systems incorporating a room temperature sapphire reference associated with a sophisticated electronics degenerating the noise of the sustaining oscillator stage [1]. On the other part, relative frequency instabilities better than few 1 × 10−15 are achieved with laboratory Cryogenic Sapphire Oscillator (CSO) in which the sapphire crystal is cooled into a large liquid Helium dewar and maintained at its turnover temperature (between 5–8 K) [2]. More reccenlty, we demonstrated an original and reliable technology incorporating a pulse-tube cooler instead of a bath cryostat thus eliminating the need for regular supplies and manual transferring of liquid helium [3]. The advent of reliable and cryocooled (CSO) open the possibility to implement such an ultra-stable reference not only in metrological laboratories with liquid helium facilities but also in remote sites like base stations for space navigation, VBLI antenna sites, … This technology is today available through a newly created business unit: ULISS{su®) [4].
{"title":"Properties of sapphire crystals elaborated with different grow technics for microwave ultra-stable oscillator applications","authors":"V. Giordano, M. Mrad, J. Masson, P. Bourgeois, Y. Kersalé, S. Grop, B. Dubois","doi":"10.1109/EFTF.2012.6502333","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502333","url":null,"abstract":"State-of-the-art microwave ultra-stable oscillators are currently based on sapphire resonator operated in whispering gallery modes in the range 5 – 12 GHz. Indeed the best near carrier phase noise is achieved with commercial systems incorporating a room temperature sapphire reference associated with a sophisticated electronics degenerating the noise of the sustaining oscillator stage [1]. On the other part, relative frequency instabilities better than few 1 × 10−15 are achieved with laboratory Cryogenic Sapphire Oscillator (CSO) in which the sapphire crystal is cooled into a large liquid Helium dewar and maintained at its turnover temperature (between 5–8 K) [2]. More reccenlty, we demonstrated an original and reliable technology incorporating a pulse-tube cooler instead of a bath cryostat thus eliminating the need for regular supplies and manual transferring of liquid helium [3]. The advent of reliable and cryocooled (CSO) open the possibility to implement such an ultra-stable reference not only in metrological laboratories with liquid helium facilities but also in remote sites like base stations for space navigation, VBLI antenna sites, … This technology is today available through a newly created business unit: ULISS{su®) [4].","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"22 1","pages":"62-65"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81719303","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.2012.6502381
C. Calosso, E. Bertacco, S. Micalizio, A. Godone, D. Calonico, G. Costanzo
In this paper we present a technique to improve the phase noise capabilities of local oscillators for atomic fountains. Specifically, the local oscillator is a combined system composed of two independent BVA oscillators. In this way, the measurement time reduces of a factor of two in comparison to the more usual local oscillator realized by one single BVA.
{"title":"OCXO ensemble as improved local oscillator for atomic fountains","authors":"C. Calosso, E. Bertacco, S. Micalizio, A. Godone, D. Calonico, G. Costanzo","doi":"10.1109/EFTF.2012.6502381","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502381","url":null,"abstract":"In this paper we present a technique to improve the phase noise capabilities of local oscillators for atomic fountains. Specifically, the local oscillator is a combined system composed of two independent BVA oscillators. In this way, the measurement time reduces of a factor of two in comparison to the more usual local oscillator realized by one single BVA.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"107 1","pages":"271-274"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77719464","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.2012.6502358
C. Rieck, R. Haas, P. Jarlemark, K. Jaldehag
Geodetic VLBI is an independent technique, which does not rely on third parties. This makes it a viable future alternative for time- and frequency transfer over long baselines. Frequency link instabilities in the order of 1.5e-15 for time periods of one day are comparable to those achievable with methods using GNSS carrier-phase observations. Data of the continuous VLBI campaign CONT11 were analyzed and compared to results from GPS PPP analysis on collocated/common clock stations.
{"title":"VLBI frequency transfer using CONT11","authors":"C. Rieck, R. Haas, P. Jarlemark, K. Jaldehag","doi":"10.1109/EFTF.2012.6502358","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502358","url":null,"abstract":"Geodetic VLBI is an independent technique, which does not rely on third parties. This makes it a viable future alternative for time- and frequency transfer over long baselines. Frequency link instabilities in the order of 1.5e-15 for time periods of one day are comparable to those achievable with methods using GNSS carrier-phase observations. Data of the continuous VLBI campaign CONT11 were analyzed and compared to results from GPS PPP analysis on collocated/common clock stations.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"150 1","pages":"163-165"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91539185","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.2012.6502378
M. Bloch, J. Ho, O. Mancini, T. Mcclelland
A high resolution, digitally tuned quartz oscillator with excellent phase noise and temperature stability has been developed for space applications and is being utilized in the Iridium NEXT constellation, the largest commercial satellite constellation in the world. Significant effort has been expanded to optimize the quartz resonator design, the double oven circuitry and the digital tuning scheme. The oscillator is implemented using readily available space qualified parts.
{"title":"Iridium-next master clock","authors":"M. Bloch, J. Ho, O. Mancini, T. Mcclelland","doi":"10.1109/EFTF.2012.6502378","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502378","url":null,"abstract":"A high resolution, digitally tuned quartz oscillator with excellent phase noise and temperature stability has been developed for space applications and is being utilized in the Iridium NEXT constellation, the largest commercial satellite constellation in the world. Significant effort has been expanded to optimize the quartz resonator design, the double oven circuitry and the digital tuning scheme. The oscillator is implemented using readily available space qualified parts.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"9 1","pages":"260-262"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87288135","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.2012.6502362
F. Constantin
The measurement of the frequency difference of rovibrational transitions from two different molecules is suggested to test the variation of the electron-to-proton mass-ratio μ. The frequency of rovibrational transitions is sensitive to μ. Small frequency splittings reached between the transitions from two isotopomers allow an enhancement relative to the variation of μ.
{"title":"Mass-ratio sensitivity of rovibrational transitions","authors":"F. Constantin","doi":"10.1109/EFTF.2012.6502362","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502362","url":null,"abstract":"The measurement of the frequency difference of rovibrational transitions from two different molecules is suggested to test the variation of the electron-to-proton mass-ratio μ. The frequency of rovibrational transitions is sensitive to μ. Small frequency splittings reached between the transitions from two isotopomers allow an enhancement relative to the variation of μ.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"12 1","pages":"178-181"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83913007","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.2012.6502364
T. Laroche, S. Ballandras, W. Daniau, Julien Garcia, K. Dbich, M. Mayer, X. Perois, K. Wagner
The simulation of finite length Surface Acoustic Wave (SAW) resonators is addressed here. Both the electro-mechanical coupling and the acoustic wave propagation in inhomogeneous space are considered through a Finite Element Analysis (FEA). The homogeneous parts of the space are treated using a Boundary Element Method (BEM) whereas the side edges of the transducer are completed by Perfectly Matched Layer (PML) method. By combining these two boundary methods BEM and PML, we are able to decrease the contributions of the losses due to the diffraction of SAW into Bulk Acoustic Waves (BAW). Thus, we can simulate the effects of real boundary filters (dual mode) on SAW resonators behavior as well as infinite passivation layer laid aver acoustic resonators.
{"title":"Simulation of finite acoustic resonators from Finite Element Analysis based on mixed Boundary Element Method/Perfectly Matched Layer","authors":"T. Laroche, S. Ballandras, W. Daniau, Julien Garcia, K. Dbich, M. Mayer, X. Perois, K. Wagner","doi":"10.1109/EFTF.2012.6502364","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502364","url":null,"abstract":"The simulation of finite length Surface Acoustic Wave (SAW) resonators is addressed here. Both the electro-mechanical coupling and the acoustic wave propagation in inhomogeneous space are considered through a Finite Element Analysis (FEA). The homogeneous parts of the space are treated using a Boundary Element Method (BEM) whereas the side edges of the transducer are completed by Perfectly Matched Layer (PML) method. By combining these two boundary methods BEM and PML, we are able to decrease the contributions of the losses due to the diffraction of SAW into Bulk Acoustic Waves (BAW). Thus, we can simulate the effects of real boundary filters (dual mode) on SAW resonators behavior as well as infinite passivation layer laid aver acoustic resonators.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"14 1","pages":"186-191"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82889667","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.2012.6502343
J. Danet, O. Kozlova, S. Guérandel, E. de Clercq
Within the frame of a Raman-Ramsey CPT clock optimisation, we present our investigations on the coherence and population lifetime measurements in Cs vapour cells. To guarantee the reliability of the coherence lifetime measurements, three different methods are compared. Very good agreement is found between two of them and results are discussed for the third. In order to increase the coherence lifetime, two techniques are tested: Firstly a buffer gas can be added in the Cs vapour cell and secondly cell walls can be coated to reduce the destructive collisions against the walls. Buffer gas is tested first and then combined to a coating. First results are presented.
{"title":"Hyperfine coherence and population lifetime in Cs vapor cells","authors":"J. Danet, O. Kozlova, S. Guérandel, E. de Clercq","doi":"10.1109/EFTF.2012.6502343","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502343","url":null,"abstract":"Within the frame of a Raman-Ramsey CPT clock optimisation, we present our investigations on the coherence and population lifetime measurements in Cs vapour cells. To guarantee the reliability of the coherence lifetime measurements, three different methods are compared. Very good agreement is found between two of them and results are discussed for the third. In order to increase the coherence lifetime, two techniques are tested: Firstly a buffer gas can be added in the Cs vapour cell and secondly cell walls can be coated to reduce the destructive collisions against the walls. Buffer gas is tested first and then combined to a coating. First results are presented.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"63 1","pages":"101-104"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89486378","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.2012.6502349
Z. Jiang, W. Lewandowski
We present the new side-product of the monthly UTC computation: the long-term time links which is monthly published since Jan. 2010 and available on the BIPM ftp site: ftp://tai.bipm.org/TimeLink/LkC/LongTerm/. The techniques used for UTC generation are now TW, GPS and GLN. If they are considered independent, we can apply them in the investigations of the measurement uncertainties and the relative long-term variation in the link calibrations. 26 months' data have been collected and analyzed in this paper. For the short term measurement instability, we have similar conclusion as presently given in the section 6 of the BIPM Circular T. It seems however, for some baselines, exist long-term variations in the link calibrations. Limited by the knowledge of the raw data, we cannot explain the causes of this instability. Except for the extreme cases, most of the annual variations are within 2 ns. This is the limit of the uncertainty of the nowadays instrumentation and calibration and should not affect the UTC generations beyond its total uncertainty.
{"title":"Inter-comparison of the UTC time transfer links","authors":"Z. Jiang, W. Lewandowski","doi":"10.1109/EFTF.2012.6502349","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502349","url":null,"abstract":"We present the new side-product of the monthly UTC computation: the long-term time links which is monthly published since Jan. 2010 and available on the BIPM ftp site: ftp://tai.bipm.org/TimeLink/LkC/LongTerm/. The techniques used for UTC generation are now TW, GPS and GLN. If they are considered independent, we can apply them in the investigations of the measurement uncertainties and the relative long-term variation in the link calibrations. 26 months' data have been collected and analyzed in this paper. For the short term measurement instability, we have similar conclusion as presently given in the section 6 of the BIPM Circular T. It seems however, for some baselines, exist long-term variations in the link calibrations. Limited by the knowledge of the raw data, we cannot explain the causes of this instability. Except for the extreme cases, most of the annual variations are within 2 ns. This is the limit of the uncertainty of the nowadays instrumentation and calibration and should not affect the UTC generations beyond its total uncertainty.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"9 1","pages":"126-132"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73032082","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.2012.6502424
B. Chanteau, O. Lopez, F. Auguste, B. Darquié, C. Chardonnet, A. Amy-Klein, W. Zhang, G. Santarelli, Y. Le Coq
We have built a frequency chain which enables to measure the absolute frequency of a laser emitting in the 28–31 THz frequency range and stabilized onto a molecular absorption line. The set-up uses an optical frequency comb and an ultrastable 1.55 µm frequency reference signal, transferred from LNE-SYRTE to LPL through an optical link. We are now progressing towards the stabilization of the mid-IR laser via the frequency comb and the extension of this technique to quantum cascade lasers. Such a development is very challenging for ultrahigh resolution molecular spectroscopy and fundamental tests of physics with molecules.
{"title":"Mid-IR frequency measurement using an optical frequency comb and a long-distance remote frequency reference","authors":"B. Chanteau, O. Lopez, F. Auguste, B. Darquié, C. Chardonnet, A. Amy-Klein, W. Zhang, G. Santarelli, Y. Le Coq","doi":"10.1109/EFTF.2012.6502424","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502424","url":null,"abstract":"We have built a frequency chain which enables to measure the absolute frequency of a laser emitting in the 28–31 THz frequency range and stabilized onto a molecular absorption line. The set-up uses an optical frequency comb and an ultrastable 1.55 µm frequency reference signal, transferred from LNE-SYRTE to LPL through an optical link. We are now progressing towards the stabilization of the mid-IR laser via the frequency comb and the extension of this technique to quantum cascade lasers. Such a development is very challenging for ultrahigh resolution molecular spectroscopy and fundamental tests of physics with molecules.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"19 1","pages":"456-458"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73143780","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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