V. Giordano, A. Hamel, P. Petit, G. Théobald, N. Dimarcq, P. Cerez, C. Audoin
An optically pumped cesium beam resonator that allows the optimization of the interaction processes among three magnetic regions has been designed. It is demonstrated that such an optically pumped cesium beam resonator can be operated at low C-field value without any loss of optical pumping efficiency. This shows that the optical pumping technique is able to improve the long-term frequency stability as well as the short-term frequency stability.<>
{"title":"New design for an efficient optically pumped cesium beam tube","authors":"V. Giordano, A. Hamel, P. Petit, G. Théobald, N. Dimarcq, P. Cerez, C. Audoin","doi":"10.1109/FREQ.1989.68847","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68847","url":null,"abstract":"An optically pumped cesium beam resonator that allows the optimization of the interaction processes among three magnetic regions has been designed. It is demonstrated that such an optically pumped cesium beam resonator can be operated at low C-field value without any loss of optical pumping efficiency. This shows that the optical pumping technique is able to improve the long-term frequency stability as well as the short-term frequency stability.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116844001","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}
Infrared and 632.7 nm laser absorption measurements have been used to characterize changes in aluminum compensation for irradiated and air-swept cultured and natural quartz. These measurements demonstrated irradiation dose effects and the competition between Al-OH and Al-h (aluminum-hole) compensation mechanisms. The laser technique was also used to localize mechanical and growth defects. By combining the results of X- and Y-direction observations for a given XY plane, information on both bulk growth defects and surface imperfections from polishing and other mechanical operations was obtained. A complete map of defects was obtained from measurements made over a range of Z-positions. The effects of /sup 60/Co gamma irradiation, air sweeping, reirradiation and annealing on grown-in OH. Al-OH and Al-h has been shown.<>
{"title":"Defect distribution mapping in quartz","authors":"P. Zecchini, H. Lipson","doi":"10.1109/FREQ.1989.68908","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68908","url":null,"abstract":"Infrared and 632.7 nm laser absorption measurements have been used to characterize changes in aluminum compensation for irradiated and air-swept cultured and natural quartz. These measurements demonstrated irradiation dose effects and the competition between Al-OH and Al-h (aluminum-hole) compensation mechanisms. The laser technique was also used to localize mechanical and growth defects. By combining the results of X- and Y-direction observations for a given XY plane, information on both bulk growth defects and surface imperfections from polishing and other mechanical operations was obtained. A complete map of defects was obtained from measurements made over a range of Z-positions. The effects of /sup 60/Co gamma irradiation, air sweeping, reirradiation and annealing on grown-in OH. Al-OH and Al-h has been shown.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127213522","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}
The principles of two-way time transfer are discussed with emphasis on its use with commercial communications satellites. The limitations imposed by the atmosphere, the equipment, and the rotating, noninertial reference system are discussed on the assumption of reciprocal paths. The advantages include: (1) operation is on a leased space segment rather than on specialized space hardware; (2) satellite location is required only to point antennas and not to compute distances; (3) effects on accuracy of time transfer by the ionosphere and troposphere are subnanosecond without modeling; (4) locations of the clocks in the ground do not need to be known better than as provided by a geodetic map-precise positions are not required; (5) simple averages of 100 1-s measurements yield about 300-ps resolution-no elaborate data analysis is required; and (6) equipment delays are easily calibrated through the use of a standard earth station acting as a transfer standard.<>
{"title":"Fundamentals of two-way time transfers by satellite","authors":"D. W. Hanson","doi":"10.1109/FREQ.1989.68861","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68861","url":null,"abstract":"The principles of two-way time transfer are discussed with emphasis on its use with commercial communications satellites. The limitations imposed by the atmosphere, the equipment, and the rotating, noninertial reference system are discussed on the assumption of reciprocal paths. The advantages include: (1) operation is on a leased space segment rather than on specialized space hardware; (2) satellite location is required only to point antennas and not to compute distances; (3) effects on accuracy of time transfer by the ionosphere and troposphere are subnanosecond without modeling; (4) locations of the clocks in the ground do not need to be known better than as provided by a geodetic map-precise positions are not required; (5) simple averages of 100 1-s measurements yield about 300-ps resolution-no elaborate data analysis is required; and (6) equipment delays are easily calibrated through the use of a standard earth station acting as a transfer standard.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"2966 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127457502","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}
A computerized method for finding velocity distributions from the Fourier transforms of Ramsey line shapes has been developed. Ramsey lineshape data taken at different excitation powers is used; a weighted average of data from three powers gives satisfactory results. The excitation amplitude parameter b is found by minimizing a quality-of-fit criterion. The method is limited to long standards by the assumption that the excitation length l is much less than the drift region length L. However, the addition of first order l/L corrections to the theory make the method usable for shorter standards. The method has been successfully tested with lineshapes theoretically generated from known velocity distributions.<>
{"title":"Velocity distributions from the Fourier transforms of Ramsey line shapes","authors":"J. Shirley","doi":"10.1109/FREQ.1989.68859","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68859","url":null,"abstract":"A computerized method for finding velocity distributions from the Fourier transforms of Ramsey line shapes has been developed. Ramsey lineshape data taken at different excitation powers is used; a weighted average of data from three powers gives satisfactory results. The excitation amplitude parameter b is found by minimizing a quality-of-fit criterion. The method is limited to long standards by the assumption that the excitation length l is much less than the drift region length L. However, the addition of first order l/L corrections to the theory make the method usable for shorter standards. The method has been successfully tested with lineshapes theoretically generated from known velocity distributions.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126567599","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}
The in-plane acceleration sensitivity of ST-cut quartz surface-wave resonators with the substrate extending beyond interior rectangular supports is analyzed. In the treatment the variational principle with all conditions appearing as natural conditions is extended in such a way as to permit interior surfaces of discontinuity with spring supports at which the approximating solution functions need not satisfy the constraint-type conditions. The resulting extensional biasing state is used in the existing perturbation integral along with the proper continuous representation of the acoustic surface wave mode shape to calculate the in-plane acceleration sensitivity for this support configuration. Results are presented as a function of planar aspect ratio for a number of overhand configurations.<>
{"title":"An analysis of the in-plane acceleration sensitivity of ST cut quartz surface wave resonators with interior rectangular supports","authors":"H. Tiersten, D.V. Shick","doi":"10.1109/FREQ.1989.68895","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68895","url":null,"abstract":"The in-plane acceleration sensitivity of ST-cut quartz surface-wave resonators with the substrate extending beyond interior rectangular supports is analyzed. In the treatment the variational principle with all conditions appearing as natural conditions is extended in such a way as to permit interior surfaces of discontinuity with spring supports at which the approximating solution functions need not satisfy the constraint-type conditions. The resulting extensional biasing state is used in the existing perturbation integral along with the proper continuous representation of the acoustic surface wave mode shape to calculate the in-plane acceleration sensitivity for this support configuration. Results are presented as a function of planar aspect ratio for a number of overhand configurations.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121070546","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}
By combining the high mechanical rigidity and low loss tangent of cryogenic sapphire with the excellent shielding and low loss properties of a superconducting cavity, the authors have developed a microwave resonator with both high electrical quality factor and very high intrinsic stability even at relatively high power. They have implemented the sapphire-loaded superconducting cavity resonator in a novel phase-stabilized loop oscillator circuit and achieved Allan variances of around 10/sup -14/ for 1 to 1000 s integrating time. This level of stability is competitive with that of the best hydrogen masers, and in fact is superior for integrating times under a few tens of seconds. An overview of the oscillator system is presented and applications and prospects for further improvement in performance are discussed.<>
{"title":"A high stability microwave oscillator based on a sapphire loaded superconducting cavity","authors":"A. Giles, S. Jones, D. Blair, M. Buckingham","doi":"10.1109/FREQ.1989.68841","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68841","url":null,"abstract":"By combining the high mechanical rigidity and low loss tangent of cryogenic sapphire with the excellent shielding and low loss properties of a superconducting cavity, the authors have developed a microwave resonator with both high electrical quality factor and very high intrinsic stability even at relatively high power. They have implemented the sapphire-loaded superconducting cavity resonator in a novel phase-stabilized loop oscillator circuit and achieved Allan variances of around 10/sup -14/ for 1 to 1000 s integrating time. This level of stability is competitive with that of the best hydrogen masers, and in fact is superior for integrating times under a few tens of seconds. An overview of the oscillator system is presented and applications and prospects for further improvement in performance are discussed.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127555239","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}
Acceleration sensitivity measurements on quartz resonators have been made as a function of temperature from -50 degrees C to +100 degrees C. 100 MHz and 10 MHz resonators were measured. Several cuts were tested including AT, SC, and IT. Acceleration sensitivity is characterized by the vector Gamma . The variation in Gamma with temperature is important in applications where Gamma is specified over a wide temperature range or when the vectorial properties of Gamma are being utilized to minimize the acceleration sensitivity in a particular direction. Results indicate that the direction and magnitude of the acceleration sensitivity vector Gamma can vary dramatically with temperature. The variations are greater at high frequencies than at low frequencies. Likewise, the variations are greater in resonators with small Gamma than in those with larger Gamma .<>
{"title":"Acceleration sensitivity as a function of temperature","authors":"W. Hanson, T. Wickard","doi":"10.1109/FREQ.1989.68900","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68900","url":null,"abstract":"Acceleration sensitivity measurements on quartz resonators have been made as a function of temperature from -50 degrees C to +100 degrees C. 100 MHz and 10 MHz resonators were measured. Several cuts were tested including AT, SC, and IT. Acceleration sensitivity is characterized by the vector Gamma . The variation in Gamma with temperature is important in applications where Gamma is specified over a wide temperature range or when the vectorial properties of Gamma are being utilized to minimize the acceleration sensitivity in a particular direction. Results indicate that the direction and magnitude of the acceleration sensitivity vector Gamma can vary dramatically with temperature. The variations are greater at high frequencies than at low frequencies. Likewise, the variations are greater in resonators with small Gamma than in those with larger Gamma .<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121788973","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}
CEPE has recently developed a family of analog temperature-compensated crystal oscillators (TCXOs). These designs use a digital method of thermal compensation to achieve a frequency stability of +or-2*10/sup -6/ under all operating conditions (temperature, power supply, load, one-year aging) with an ultralow power consumption (300 mu A, 3V). Studies of system requirements and analog TCXO capabilities led to the development of TCXOs using a numerical method for thermal compensation called digital temperature compensated crystal oscillator (DTCXOs). The method used to realize the digital compensation and the results obtained on a first batch of DTCXOs are presented.<>
{"title":"Low profile high stability digital TCXO: ultra low power consumption TCXO","authors":"V. Candelier, G. Caret, A. Debaisieux","doi":"10.1109/FREQ.1989.68834","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68834","url":null,"abstract":"CEPE has recently developed a family of analog temperature-compensated crystal oscillators (TCXOs). These designs use a digital method of thermal compensation to achieve a frequency stability of +or-2*10/sup -6/ under all operating conditions (temperature, power supply, load, one-year aging) with an ultralow power consumption (300 mu A, 3V). Studies of system requirements and analog TCXO capabilities led to the development of TCXOs using a numerical method for thermal compensation called digital temperature compensated crystal oscillator (DTCXOs). The method used to realize the digital compensation and the results obtained on a first batch of DTCXOs are presented.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133945155","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}
An external cavity diode laser is developed for optical pumping and detection of a cesium atomic beam. The laser is about 2*4*5 cm in size, is tunable to any wavelength over a 40-nm range, and emits two collimated beams of light with power outputs to 6 mW each. The laser spectrum consists of a single longitudinal mode with every narrow linewidth. When locked to a single hyperfine transition in atomic cesium, the signal-to-noise ratio (SNR) for fluorescence detection of the transition far exceeds the SNR observed when an unmodified laser diode is used.<>
{"title":"Low noise laser for optically pumped cesium standards","authors":"L. Lewis","doi":"10.1109/FREQ.1989.68850","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68850","url":null,"abstract":"An external cavity diode laser is developed for optical pumping and detection of a cesium atomic beam. The laser is about 2*4*5 cm in size, is tunable to any wavelength over a 40-nm range, and emits two collimated beams of light with power outputs to 6 mW each. The laser spectrum consists of a single longitudinal mode with every narrow linewidth. When locked to a single hyperfine transition in atomic cesium, the signal-to-noise ratio (SNR) for fluorescence detection of the transition far exceeds the SNR observed when an unmodified laser diode is used.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132348586","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}
The design and performance of surface acoustic wave (SAW) resonator oscillators using techniques for obtaining low phase noise levels are described. These oscillators are very low phase noise engineering prototypes which also meet other vital system requirements, such as temperature stability and vibration sensitivity. A 500-MHz version has a phase noise floor of -177 dBc/Hz and a flicker noise level of -132 dBc/Hz at 1 kHz offset. An L-band (frequency-doubled) version has noise levels of -171 dBc/Hz and -126 dBc/Hz, respectively. Other important performance parameters that are discussed include: temperature dependence of frequency and output power, vibration sensitivity, frequency tuning characteristics, spurious levels, load pulling, voltage pushing and long-term frequency stability.<>
{"title":"Low-noise SAW resonator oscillators","authors":"T. Parker, G. K. Montress","doi":"10.1109/FREQ.1989.68919","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68919","url":null,"abstract":"The design and performance of surface acoustic wave (SAW) resonator oscillators using techniques for obtaining low phase noise levels are described. These oscillators are very low phase noise engineering prototypes which also meet other vital system requirements, such as temperature stability and vibration sensitivity. A 500-MHz version has a phase noise floor of -177 dBc/Hz and a flicker noise level of -132 dBc/Hz at 1 kHz offset. An L-band (frequency-doubled) version has noise levels of -171 dBc/Hz and -126 dBc/Hz, respectively. Other important performance parameters that are discussed include: temperature dependence of frequency and output power, vibration sensitivity, frequency tuning characteristics, spurious levels, load pulling, voltage pushing and long-term frequency stability.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114608104","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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