Pub Date : 2012-04-23DOI: 10.1109/EFTF.2012.6502397
A. Kanj, J. Achkar, D. Rovera
The Two-Way Satellite Time and Frequency Transfer (TWSTFT) is widely used by the time institutes to compare ground atomic clocks and contributes to the production of the Temps Atomique International (TAI) calculated by the BIPM. In the past, TWSTFT links have frequency stability of 1×10−15 at one day [1], and since the last three years, two-way links became more and more noisy and the frequency stability has been degraded which has motivated the present work. In order to improve the performance of the TWSTFT technique, we focused on the principle parameters that impact the measurements stability and accuracy. In completion to the previous work [2] on the measurement noise in TWSTFT, we analyzed the impact of the changes of reference clock, satellite and satellite transponder on the two-way link instability over the period of the last five years. In addition, we studied the contribution in measurement noise on the two-way links of the following parameters: the chip-rates of the pseudo random noise modulation of the transmitted signal, the power of the transmitted and received signals. We also use the satellite simulator to determine the dependence of the chip rates on the delay difference of the OP ground stations. We completed the work in analyzing the variation of the short term residual noise fluctuations [3] and the carrier to noise ratio of the received signals in function of the previously listed parameters. Different results are presented in this paper and possible issues for improvement of the two-way links are proposed.
{"title":"Analysis of the impact of measurement noise on the TWSTFT stability","authors":"A. Kanj, J. Achkar, D. Rovera","doi":"10.1109/EFTF.2012.6502397","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502397","url":null,"abstract":"The Two-Way Satellite Time and Frequency Transfer (TWSTFT) is widely used by the time institutes to compare ground atomic clocks and contributes to the production of the Temps Atomique International (TAI) calculated by the BIPM. In the past, TWSTFT links have frequency stability of 1×10−15 at one day [1], and since the last three years, two-way links became more and more noisy and the frequency stability has been degraded which has motivated the present work. In order to improve the performance of the TWSTFT technique, we focused on the principle parameters that impact the measurements stability and accuracy. In completion to the previous work [2] on the measurement noise in TWSTFT, we analyzed the impact of the changes of reference clock, satellite and satellite transponder on the two-way link instability over the period of the last five years. In addition, we studied the contribution in measurement noise on the two-way links of the following parameters: the chip-rates of the pseudo random noise modulation of the transmitted signal, the power of the transmitted and received signals. We also use the satellite simulator to determine the dependence of the chip rates on the delay difference of the OP ground stations. We completed the work in analyzing the variation of the short term residual noise fluctuations [3] and the carrier to noise ratio of the received signals in function of the previously listed parameters. Different results are presented in this paper and possible issues for improvement of the two-way links are proposed.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"151 1","pages":"340-344"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76839830","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.2012.6502340
M. Pellaton, C. Affolderbach, G. Mileti, R. Straessle, D. Briand, N. D. de Rooij
We present a study of our in-house made tetracontane wall-coated 87Rb vapour cells for rubidium atomic clock applications. Evolution of the double-resonance (DR) signal during the so-called ripening process of these cells is measured and interpreted. Intrinsic properties of the coated cells post ripening are presented. Intrinsic linewidths below 70 Hz, and moderate temperature coefficients (1.5 × 10−10 /K) are promising cell properties in view of highly compact and miniature atomic clocks.
{"title":"Wall-coated cells for Rb atomic clocks: Study of the ripening process by double-resonance spectroscopy","authors":"M. Pellaton, C. Affolderbach, G. Mileti, R. Straessle, D. Briand, N. D. de Rooij","doi":"10.1109/EFTF.2012.6502340","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502340","url":null,"abstract":"We present a study of our in-house made tetracontane wall-coated 87Rb vapour cells for rubidium atomic clock applications. Evolution of the double-resonance (DR) signal during the so-called ripening process of these cells is measured and interpreted. Intrinsic properties of the coated cells post ripening are presented. Intrinsic linewidths below 70 Hz, and moderate temperature coefficients (1.5 × 10−10 /K) are promising cell properties in view of highly compact and miniature atomic clocks.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"53 1","pages":"87-90"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83287115","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.2012.6502380
S. Grop, B. Dubois, J. Masson, P. Bourgeois, Y. Kersalé, E. Rubiola, G. Haye, V. Giordano
In this paper we present the direct comparison of two microwave Cryocooled Sapphire Oscillators demonstrating a relative frequency stability better than 2×10−15 at short term and of the order of 1×10−14 over one day integration. We also report the frequency stability evaluation of a microwave signal generated from a planar waveguide external cavity laser (PW-ECL) referenced to a Fabry-Perot cavity through optical-to-microwave frequency division with a commercial Er:fiber optical frequency comb owned by the “laboratoire temps-fréquence” (LTF) of the university of Neuchâtel, Switzerland, and the phase noise measurement of the engineering model of the Pharao clock frequency synthesis owned by the “Centre National d'Etudes Spatiales” (CNES) at Toulouse, France. These lastest results were obtained by moving one of our Cryogenic Sapphire Oscillator (CSO) from the FEMTO-ST Institute to these two metrological sites.
{"title":"Direct comparison of two Cryocooled Sapphire Oscillators presenting relative frequency instability at 10−15","authors":"S. Grop, B. Dubois, J. Masson, P. Bourgeois, Y. Kersalé, E. Rubiola, G. Haye, V. Giordano","doi":"10.1109/EFTF.2012.6502380","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502380","url":null,"abstract":"In this paper we present the direct comparison of two microwave Cryocooled Sapphire Oscillators demonstrating a relative frequency stability better than 2×10−15 at short term and of the order of 1×10−14 over one day integration. We also report the frequency stability evaluation of a microwave signal generated from a planar waveguide external cavity laser (PW-ECL) referenced to a Fabry-Perot cavity through optical-to-microwave frequency division with a commercial Er:fiber optical frequency comb owned by the “laboratoire temps-fréquence” (LTF) of the university of Neuchâtel, Switzerland, and the phase noise measurement of the engineering model of the Pharao clock frequency synthesis owned by the “Centre National d'Etudes Spatiales” (CNES) at Toulouse, France. These lastest results were obtained by moving one of our Cryogenic Sapphire Oscillator (CSO) from the FEMTO-ST Institute to these two metrological sites.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"6 1","pages":"267-270"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88848583","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.2012.6502384
M. Peca, M. Vacek, V. Michálek
Architecture of a time-to-digit converter (TDC) is presented. TDC is an electronic device which measures time of arrival of discrete electronic pulses, with respect to reference time base. Our work on TDC is motivated by its applications in field of long-range laser distance measurement and time synchronization. Unlike earlier time interpolation methods, we have chosen all-digital approach based on pulse propagation through tapped delay line. We do not expect it could outperform recent invention of time interpolation using narrow-band filter excitation [1], [2]. However, our approach relies on a standard digital circuitry only. With space applications in mind, we are implementing the TDC into a space qualified, radiation-tolerant field-programmable gate array (FPGA). On top of related works [4] and [5] on all-digital TDCs, delay line, we try to gather more complete information about the sampled pulse. It is done by sampling of whole bit vector, corresponding to all of the delay line taps. A calibration method based on random pulse source is discussed, including preliminary results. Impact of physical FPGA cell placement on resulting time measurement granularity is observed. Actually measured jitter distribution is compared to normal distribution function, giving an insight of absolute accuracy limit of our approach within the given FPGA platform.
{"title":"Time-to-Digit Converter Based on radiation-tolerant FPGA","authors":"M. Peca, M. Vacek, V. Michálek","doi":"10.1109/EFTF.2012.6502384","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502384","url":null,"abstract":"Architecture of a time-to-digit converter (TDC) is presented. TDC is an electronic device which measures time of arrival of discrete electronic pulses, with respect to reference time base. Our work on TDC is motivated by its applications in field of long-range laser distance measurement and time synchronization. Unlike earlier time interpolation methods, we have chosen all-digital approach based on pulse propagation through tapped delay line. We do not expect it could outperform recent invention of time interpolation using narrow-band filter excitation [1], [2]. However, our approach relies on a standard digital circuitry only. With space applications in mind, we are implementing the TDC into a space qualified, radiation-tolerant field-programmable gate array (FPGA). On top of related works [4] and [5] on all-digital TDCs, delay line, we try to gather more complete information about the sampled pulse. It is done by sampling of whole bit vector, corresponding to all of the delay line taps. A calibration method based on random pulse source is discussed, including preliminary results. Impact of physical FPGA cell placement on resulting time measurement granularity is observed. Actually measured jitter distribution is compared to normal distribution function, giving an insight of absolute accuracy limit of our approach within the given FPGA platform.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"42 1","pages":"286-289"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88479429","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.2012.6502401
H. Narita, J. Amagai, M. Aida, Y. Takahashi, I. Nakazawa, M. Nakamura, H. Ujihara, S. Hama
As we designed and constructed the QZSS mobile station, we transported it to Okinawa Electromagnetic Technology Center and Kashima Space Technology Center. At each place we carried out time comparison experiments. This paper describes some results of the time comparison experiments.
{"title":"Development of QZSS-mobile station","authors":"H. Narita, J. Amagai, M. Aida, Y. Takahashi, I. Nakazawa, M. Nakamura, H. Ujihara, S. Hama","doi":"10.1109/EFTF.2012.6502401","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502401","url":null,"abstract":"As we designed and constructed the QZSS mobile station, we transported it to Okinawa Electromagnetic Technology Center and Kashima Space Technology Center. At each place we carried out time comparison experiments. This paper describes some results of the time comparison experiments.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"11 1","pages":"361-364"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76156954","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.2012.6502423
S. Raupach, T. Legero, A. Bauch, C. Grebing, C. Hagemann, T. Kessler, A. Koczwara, B. Lipphardt, H. Schnatz, U. Sterr, G. Grosche
We describe a system that combines a cavity-stabilized laser, a hydrogen maser and a cesium fountain clock. It provides an optical reference frequency that over the course of half a day drifts with less than 100 µHz/s. Furthermore it allows for a convenient measurement of an absolute frequency in the optical domain.
{"title":"A small-linewidth absolute optical frequency source","authors":"S. Raupach, T. Legero, A. Bauch, C. Grebing, C. Hagemann, T. Kessler, A. Koczwara, B. Lipphardt, H. Schnatz, U. Sterr, G. Grosche","doi":"10.1109/EFTF.2012.6502423","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502423","url":null,"abstract":"We describe a system that combines a cavity-stabilized laser, a hydrogen maser and a cesium fountain clock. It provides an optical reference frequency that over the course of half a day drifts with less than 100 µHz/s. Furthermore it allows for a convenient measurement of an absolute frequency in the optical domain.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"41 1","pages":"453-455"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76780086","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.2012.6502388
X. Liu, E. Kroemer, J. Merolla, R. Boudot
This paper reports the key development steps of a Bi-Frequency Bi-Polarization (BiFBiP) laser system that generates from a single externally-modulated Distributed Feedback (DFB) laser source two phase-coherent optical lines resonant on the Cs D1 line (894.6 nm), frequency-splitted by 9.192 GHz and exhibiting linear crossed polarizations. Two different architectures, based on electro-optic modulators as key components for optical sidebands generation, are presented. Residual frequency stability performances of the DFB laser source are measured to be less than 10−11 for integration times up to 200 s. Phase noise performances of the optically carried microwave signal as well as polarization analysis at the output of the BiFBiP system are reported. Using this laser system, Coherent Population Trapping (CPT) resonances with contrast up to 5.8 % in a mm-scale vapor cell and 22 % in a cm-scale cell are preliminary reported.
{"title":"Towards the detection of high-contrast Cs CPT resonances using a single modulated diode laser","authors":"X. Liu, E. Kroemer, J. Merolla, R. Boudot","doi":"10.1109/EFTF.2012.6502388","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502388","url":null,"abstract":"This paper reports the key development steps of a Bi-Frequency Bi-Polarization (BiFBiP) laser system that generates from a single externally-modulated Distributed Feedback (DFB) laser source two phase-coherent optical lines resonant on the Cs D1 line (894.6 nm), frequency-splitted by 9.192 GHz and exhibiting linear crossed polarizations. Two different architectures, based on electro-optic modulators as key components for optical sidebands generation, are presented. Residual frequency stability performances of the DFB laser source are measured to be less than 10−11 for integration times up to 200 s. Phase noise performances of the optically carried microwave signal as well as polarization analysis at the output of the BiFBiP system are reported. Using this laser system, Coherent Population Trapping (CPT) resonances with contrast up to 5.8 % in a mm-scale vapor cell and 22 % in a cm-scale cell are preliminary reported.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"11 1","pages":"304-308"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74752960","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.2012.6502372
V. Stofanik, Z. Brezović, M. Minárik
In this paper we illustrate our experimental investigations of drive level dependencies of two higher overtones (the 5th and the 7th ones), as well as of the main mode (the 3rd overtone) of several different stress compensated (SC) quartz resonators. The drive level dependencies of basic parameters in the simple Butterworth-Van Dyke one-port equivalent circuit of the particular mode were derived from the impedance vs. frequency responses measured in the vicinity of the particular modes, while temperature of the investigated resonator was maintained approximately at the lower turnover point temperature of the main mode. In the 3rd overtone 10-MHz SC quartz resonators, for example, the 5th overtone or the 7th overtone (the c-modes, i.e. the slow thickness-shear modes of vibration) can be exited simultaneously along with the main c-mode, with assistance of an appropriate dual-mode or multi-mode crystal oscillator (DMXO or MMXO); and the resonator self-temperature-sensing can be reliably implemented [1], [2], [3]. Level of amplitudes of particular modes, which are simultaneously excited in DMXO or MMXO, has impact on short-term, as well as on long-term frequency instabilities of generated signals; hence drive levels of individual c-modes have to be set-up properly in the oscillator circuit.
{"title":"Investigation of drive level dependencies of higher overtones in SC quartz resonators","authors":"V. Stofanik, Z. Brezović, M. Minárik","doi":"10.1109/EFTF.2012.6502372","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502372","url":null,"abstract":"In this paper we illustrate our experimental investigations of drive level dependencies of two higher overtones (the 5th and the 7th ones), as well as of the main mode (the 3rd overtone) of several different stress compensated (SC) quartz resonators. The drive level dependencies of basic parameters in the simple Butterworth-Van Dyke one-port equivalent circuit of the particular mode were derived from the impedance vs. frequency responses measured in the vicinity of the particular modes, while temperature of the investigated resonator was maintained approximately at the lower turnover point temperature of the main mode. In the 3rd overtone 10-MHz SC quartz resonators, for example, the 5th overtone or the 7th overtone (the c-modes, i.e. the slow thickness-shear modes of vibration) can be exited simultaneously along with the main c-mode, with assistance of an appropriate dual-mode or multi-mode crystal oscillator (DMXO or MMXO); and the resonator self-temperature-sensing can be reliably implemented [1], [2], [3]. Level of amplitudes of particular modes, which are simultaneously excited in DMXO or MMXO, has impact on short-term, as well as on long-term frequency instabilities of generated signals; hence drive levels of individual c-modes have to be set-up properly in the oscillator circuit.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"20 1","pages":"227-234"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80884512","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.2012.6502366
R. Lucklum
A phononic crystal device is investigated as a sensor platform combining band gap engineering with resonant transmission. A slit cavity perpendicular to the propagation direction of ultrasound and placed in the middle of a phononic crystal causes a peak in the transmission spectrum with the peak frequency strongly dependent on the speed of sound of the liquid filling the slit. A resonant transmission peak through a plate regularly perforated by holes arranged in square lattice can also be found in case of normal incidence of sound. In this arrangement the peak frequency is strongly dependent on speed of sound of the liquid surrounding the plate and filling the holes. These findings are the basis of two resonant liquid sensor platforms based on phononic crystals.
{"title":"Phononic crystal sensors","authors":"R. Lucklum","doi":"10.1109/EFTF.2012.6502366","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502366","url":null,"abstract":"A phononic crystal device is investigated as a sensor platform combining band gap engineering with resonant transmission. A slit cavity perpendicular to the propagation direction of ultrasound and placed in the middle of a phononic crystal causes a peak in the transmission spectrum with the peak frequency strongly dependent on the speed of sound of the liquid filling the slit. A resonant transmission peak through a plate regularly perforated by holes arranged in square lattice can also be found in case of normal incidence of sound. In this arrangement the peak frequency is strongly dependent on speed of sound of the liquid surrounding the plate and filling the holes. These findings are the basis of two resonant liquid sensor platforms based on phononic crystals.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"75 1","pages":"196-199"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89903085","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.2012.6502417
L. Sliwczynski, P. Krehlik, L. Buczek, M. Lipinski, J. Kołodziej
In the paper the results of laboratory experiments are presented concerning the time and frequency transfer in 480 km long electronically stabilized fiber optic link. The fiber optic link comprised nine spooled spans with attenuation between 5–15 dB and eight custom-built bidirectional fiber amplifiers. The Allan deviation measured for frequency transfer at one-day averaging was around 4·10−17, whereas time deviation for 1PPS signal was in the range 650–900 fs for averaging times between 103–105 s.
{"title":"Fiber optic RF frequency transfer on the distance of 480 km with the active stabilization of the propagation delay","authors":"L. Sliwczynski, P. Krehlik, L. Buczek, M. Lipinski, J. Kołodziej","doi":"10.1109/EFTF.2012.6502417","DOIUrl":"https://doi.org/10.1109/EFTF.2012.6502417","url":null,"abstract":"In the paper the results of laboratory experiments are presented concerning the time and frequency transfer in 480 km long electronically stabilized fiber optic link. The fiber optic link comprised nine spooled spans with attenuation between 5–15 dB and eight custom-built bidirectional fiber amplifiers. The Allan deviation measured for frequency transfer at one-day averaging was around 4·10<sup>−17</sup>, whereas time deviation for 1PPS signal was in the range 650–900 fs for averaging times between 10<sup>3</sup>–10<sup>5</sup> s.","PeriodicalId":6409,"journal":{"name":"2012 European Frequency and Time Forum","volume":"45 1","pages":"424-426"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79520720","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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