D. Howe, D. W. Hanson, J. Jespersen, M. Lombardi, W. Klepczynski, P. Wheeler, M. Miranian, W. Powell, J. Jeffries, A. Myers
Time comparison data between UTC US Naval Observatory (USNO) and UTC US National Institute of Standards and Technology (NIST) is presented along with some analysis of that data. Second-to-second raw difference data is white and with no discernible slope for a 300-s measurement; a simple mean is computed for the value of the time comparison. Long-term sigma /sub y/( tau ) results are consistent with expected results of a comparison between NIST and USNO, and in-cabinet loop tests of the two-way satellite equipment point to system noise being a factor of 10 below the stability of these results. Therefore the noise contribution due to the two-way time transfer method is assumed to be negligible. The results show that the measurement time could be reduced from 300 s to 100 s with little or no compromise in precision even with a C/N/sub 0/ as low as 55 dB-Hz.<>
{"title":"NIST-USNO time comparisons using two-way satellite time transfers","authors":"D. Howe, D. W. Hanson, J. Jespersen, M. Lombardi, W. Klepczynski, P. Wheeler, M. Miranian, W. Powell, J. Jeffries, A. Myers","doi":"10.1109/FREQ.1989.68864","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68864","url":null,"abstract":"Time comparison data between UTC US Naval Observatory (USNO) and UTC US National Institute of Standards and Technology (NIST) is presented along with some analysis of that data. Second-to-second raw difference data is white and with no discernible slope for a 300-s measurement; a simple mean is computed for the value of the time comparison. Long-term sigma /sub y/( tau ) results are consistent with expected results of a comparison between NIST and USNO, and in-cabinet loop tests of the two-way satellite equipment point to system noise being a factor of 10 below the stability of these results. Therefore the noise contribution due to the two-way time transfer method is assumed to be negligible. The results show that the measurement time could be reduced from 300 s to 100 s with little or no compromise in precision even with a C/N/sub 0/ as low as 55 dB-Hz.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"1 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":"130634570","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}
J. Messina, D. Bowman, R. Filler, R. Lindenmuth, V. Rosati, S. Schodowski
The results of long-term testing of the tactical miniature crystal oscillator (TMXO) are presented. The TMXO uses high-vacuum thermal insulation, microelectronic packaging, and a precision ceramic-flatpack-enclosed SC-cut crystal. Engineering models and pilot-production models, delivered under a Manufacturing Methods and Technology effort with the Bendix Division of Allied Corporation, were subjected to a variety of tests that included turn-on/turn-off at temperature extremes, input-power aging, and frequency aging. The testing verified the ability of the TMXO to maintain vacuum integrity over a reasonable lifetime (10 years).<>
{"title":"Results of long term testing of tactical miniature crystal oscillators","authors":"J. Messina, D. Bowman, R. Filler, R. Lindenmuth, V. Rosati, S. Schodowski","doi":"10.1109/FREQ.1989.68833","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68833","url":null,"abstract":"The results of long-term testing of the tactical miniature crystal oscillator (TMXO) are presented. The TMXO uses high-vacuum thermal insulation, microelectronic packaging, and a precision ceramic-flatpack-enclosed SC-cut crystal. Engineering models and pilot-production models, delivered under a Manufacturing Methods and Technology effort with the Bendix Division of Allied Corporation, were subjected to a variety of tests that included turn-on/turn-off at temperature extremes, input-power aging, and frequency aging. The testing verified the ability of the TMXO to maintain vacuum integrity over a reasonable lifetime (10 years).<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"10 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":"131246537","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}
M. Bloch, M. Meirs, J. Ho, J. Vig, S.S. Schodowski
Low-power timekeeping methods have been developed that provide improved accuracy over the full military temperature range. These methods provide tradeoffs of accuracy vs. power consumption dependent upon the application. The system achieves this performance by using a microcomputer-compensated crystal oscillator (MCXO) to periodically update a low-power oscillator clock system. This technique does not substantially increase the power dissipation because the MCSO is turned on for only a few seconds each time to recalibrate the clock oscillator frequency. Using this technique, a clock oscillator of +or-5*10/sup -6/ over the temperature range can be made to approach the +or-*10/sup -8/ accuracy of the MCXO.<>
{"title":"Low power timekeeping","authors":"M. Bloch, M. Meirs, J. Ho, J. Vig, S.S. Schodowski","doi":"10.1109/FREQ.1989.68856","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68856","url":null,"abstract":"Low-power timekeeping methods have been developed that provide improved accuracy over the full military temperature range. These methods provide tradeoffs of accuracy vs. power consumption dependent upon the application. The system achieves this performance by using a microcomputer-compensated crystal oscillator (MCXO) to periodically update a low-power oscillator clock system. This technique does not substantially increase the power dissipation because the MCSO is turned on for only a few seconds each time to recalibrate the clock oscillator frequency. Using this technique, a clock oscillator of +or-5*10/sup -6/ over the temperature range can be made to approach the +or-*10/sup -8/ accuracy of the MCXO.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"1 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":"132150030","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}
Maskless adjustment of quartz crystals has been developed using laser-induced deposition of material. The process uses an excimer laser operating in the UV, which dissociates volatile precursors and leaves a stable material. This material is deposited where the laser strikes the surface of the crystal and hence can be used to adjust it. A simple means of beam steering has been developed and the necessary process parameters such as laser fluence and precursor flow rate have been investigated. Problems such as window fouling and gas phase reactions have been solved. Up to 2000 p.p.m. of adjustment to crystal resonators of up to 125-MHz fundamental has been demonstrated. Initial aging of canned crystals look very promising.<>
{"title":"Crystal adjustment by laser chemical deposition","authors":"R. Williamson","doi":"10.1109/FREQ.1989.68925","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68925","url":null,"abstract":"Maskless adjustment of quartz crystals has been developed using laser-induced deposition of material. The process uses an excimer laser operating in the UV, which dissociates volatile precursors and leaves a stable material. This material is deposited where the laser strikes the surface of the crystal and hence can be used to adjust it. A simple means of beam steering has been developed and the necessary process parameters such as laser fluence and precursor flow rate have been investigated. Problems such as window fouling and gas phase reactions have been solved. Up to 2000 p.p.m. of adjustment to crystal resonators of up to 125-MHz fundamental has been demonstrated. Initial aging of canned crystals look very promising.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"113 1-2 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":"132878683","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 acoustic loss and frequency versus temperature spectra are measured as a function of radiation dose for a number of matching Na-swept crystals and for H-swept AT-cut quartz crystals. As expected, large positive frequency offsets at both the upper and lower turnovers were observed for the Na-swept crystals. However, the magnitude of the offset was consistently much smaller than the change in height of the strong 53 K (5 MHz) Al-Na loss peak. This smaller offset was caused by a change in the 'apparent' angle of the crystal that comes about when the Al-Na center is replaced by the Al-OH or Al-hole center. The offsets of the swept crystals were usually smaller than those of the unswept samples. Only part of the observed fractional frequency offset at the turnovers could be explained by summing the heights of the loss peak changes. An additional radiation-induced offset was observed at temperatures below 15 K where the frequency versus temperature curves flatten out.<>
对于一些匹配的na扫描晶体和h扫描at切割石英晶体，测量了声损失和频率随温度谱作为辐射剂量的函数。正如预期的那样，在na扫描晶体的上下翻转处观察到大的正频率偏移。然而，偏移量的大小始终远小于强53 K (5 MHz) Al-Na损耗峰高度的变化。这种较小的偏移是由于当Al-Na中心被Al-OH或Al-hole中心取代时，晶体的“视角”发生了变化。扫描晶体的偏移量通常小于未扫描样品的偏移量。只有部分观察到的分数频率偏移可以用损耗峰变化的总和来解释。在温度低于15 K时，观察到额外的辐射引起的偏移，此时频率与温度曲线趋于平缓。
{"title":"Radiation induced frequency offsets and acoustic loss in AT-cut quartz crystals","authors":"J.J. Martin","doi":"10.1109/FREQ.1989.68913","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68913","url":null,"abstract":"The acoustic loss and frequency versus temperature spectra are measured as a function of radiation dose for a number of matching Na-swept crystals and for H-swept AT-cut quartz crystals. As expected, large positive frequency offsets at both the upper and lower turnovers were observed for the Na-swept crystals. However, the magnitude of the offset was consistently much smaller than the change in height of the strong 53 K (5 MHz) Al-Na loss peak. This smaller offset was caused by a change in the 'apparent' angle of the crystal that comes about when the Al-Na center is replaced by the Al-OH or Al-hole center. The offsets of the swept crystals were usually smaller than those of the unswept samples. Only part of the observed fractional frequency offset at the turnovers could be explained by summing the heights of the loss peak changes. An additional radiation-induced offset was observed at temperatures below 15 K where the frequency versus temperature curves flatten out.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"1 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":"124339225","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 contoured AT- and SC-cut quartz crystal resonators with the same support configuration is performed. The extensional biasing deformation field is determined by means of the variational approximation procedure using the variational principle in which all conditions appear as natural conditions. The resulting extensional biasing state is used in the existing perturbation equation along with the mode shapes of the contoured resonators to calculate the in-plane acceleration sensitivities. Results are presented as a function of the planar aspect ratio and orientation of the rectangle.<>
{"title":"An analysis of the in-plane acceleration sensitivity of contoured quartz resonators rigidly supported along the edges","authors":"D.V. Shick, H. Tiersten","doi":"10.1109/FREQ.1989.68896","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68896","url":null,"abstract":"The in-plane acceleration sensitivity of contoured AT- and SC-cut quartz crystal resonators with the same support configuration is performed. The extensional biasing deformation field is determined by means of the variational approximation procedure using the variational principle in which all conditions appear as natural conditions. The resulting extensional biasing state is used in the existing perturbation equation along with the mode shapes of the contoured resonators to calculate the in-plane acceleration sensitivities. Results are presented as a function of the planar aspect ratio and orientation of the rectangle.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"134 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":"116590300","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}
Measurements are reported of the magnitude and phase of microwave transmission through thin films of Y-Ba-Cu-O on MgO substrate in the presence of a small magnetic field. Such films are used for the construction of high-Q superconducting cavity. The real and imaginary parts of the complex conductivity and their dependence on temperature and magnetic field are evaluated. It is shown that the presence of a constant magnetic field appreciably changes the magnitude and phase of the microwave transmission through superconducting films, while the presence of an oscillating field modulates it with the generation of many high-order harmonics. This strong nonlinear behavior may be explained by a model that assumes an array of Josephson junctions between superconducting grains.<>
{"title":"Microwave properties of thin films of high-T/sub c/ superconductor Y-Ba-Cu-O","authors":"M. Golosovsky, D. Davidov, C. Retorri, A. Stern","doi":"10.1109/FREQ.1989.68844","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68844","url":null,"abstract":"Measurements are reported of the magnitude and phase of microwave transmission through thin films of Y-Ba-Cu-O on MgO substrate in the presence of a small magnetic field. Such films are used for the construction of high-Q superconducting cavity. The real and imaginary parts of the complex conductivity and their dependence on temperature and magnetic field are evaluated. It is shown that the presence of a constant magnetic field appreciably changes the magnitude and phase of the microwave transmission through superconducting films, while the presence of an oscillating field modulates it with the generation of many high-order harmonics. This strong nonlinear behavior may be explained by a model that assumes an array of Josephson junctions between superconducting grains.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"31 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":"123540732","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}
In the two-way time transfer method signals are exchanged back and forth, via a satellite transponder, between the master and slave stations. Because of the two-way signal exchanges in path delay cancels out in the relevant calculations, leaving only the difference in the clock readings at the master and slave stations. However, the cancelling of path delay is critically dependent on the assumption that the signal path delay from master to satellite to slave is equal to the delay from slave to satellite to master-that is, the path are reciprocal. In actual practice, the uplink signal frequencies from both master and slave to the satellite differ from the downlink frequencies from the satellite to the master and slave stations, so that the reciprocity assumption does not hold over the ionospheric portion of the path. Thus one must make calculations to see if the lack of reciprocity is significant in relation to the degree of timing accuracy required. It is possible, under some circumstances, to measure the degree of nonreciprocity directly because the signals relayed by the satellite are generally available at both the slave and master stations simultaneously.<>
{"title":"Impact of atmospheric non-reciprocity on satellite two-way time transfer","authors":"J. Jespersen","doi":"10.1109/FREQ.1989.68863","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68863","url":null,"abstract":"In the two-way time transfer method signals are exchanged back and forth, via a satellite transponder, between the master and slave stations. Because of the two-way signal exchanges in path delay cancels out in the relevant calculations, leaving only the difference in the clock readings at the master and slave stations. However, the cancelling of path delay is critically dependent on the assumption that the signal path delay from master to satellite to slave is equal to the delay from slave to satellite to master-that is, the path are reciprocal. In actual practice, the uplink signal frequencies from both master and slave to the satellite differ from the downlink frequencies from the satellite to the master and slave stations, so that the reciprocity assumption does not hold over the ionospheric portion of the path. Thus one must make calculations to see if the lack of reciprocity is significant in relation to the degree of timing accuracy required. It is possible, under some circumstances, to measure the degree of nonreciprocity directly because the signals relayed by the satellite are generally available at both the slave and master stations simultaneously.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"29 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":"123599567","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 temperature test station has been developed for testing moderate quantities of crystal resonators. The primary function of this station is to accurately measure the frequency versus temperature characteristics of quartz crystals of all types. Additional features include curve-fitting routines to characterize the frequency-temperature function and the derivation of the crystal's equivalent circuit parameters as a function of temperature. In this system all electrical tests are performed by a network analyzer which interfaces directly with a computer. All functions of the network analyzer are controllable through the computer interface. Crystal measurements are performed with an HP 3577A network analyzer using the general methods outlined in EIA Crystal Measurement Standard 512. This work describes the equipment used in this station and provides a general description of the custom software used to operate the system. Estimates of system accuracy and repeatability are provided. Test results for a variety of crystals are given.<>
{"title":"Precision temperature test station for quartz crystals","authors":"R. Kinsman, D. Ryback","doi":"10.1109/FREQ.1989.68882","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68882","url":null,"abstract":"A temperature test station has been developed for testing moderate quantities of crystal resonators. The primary function of this station is to accurately measure the frequency versus temperature characteristics of quartz crystals of all types. Additional features include curve-fitting routines to characterize the frequency-temperature function and the derivation of the crystal's equivalent circuit parameters as a function of temperature. In this system all electrical tests are performed by a network analyzer which interfaces directly with a computer. All functions of the network analyzer are controllable through the computer interface. Crystal measurements are performed with an HP 3577A network analyzer using the general methods outlined in EIA Crystal Measurement Standard 512. This work describes the equipment used in this station and provides a general description of the custom software used to operate the system. Estimates of system accuracy and repeatability are provided. Test results for a variety of crystals are given.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"60 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":"124690079","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}
Several factors are reviewed for specifying and measuring the frequency vs. temperature (f-T) characteristics of precision quartz crystal oscillators. Topics include static vs. dynamic measurement, thermal time constant, activity dips, condensables, hysteresis, and trim effect. This work reviews some f-T considerations that are not discussed in detail in MIL-0-55310.<>
{"title":"Specification and measurement of the frequency versus temperature characteristics of crystal oscillators","authors":"R. Filler, V. Rosati, S.S. Schodowski, J. Vig","doi":"10.1109/FREQ.1989.68874","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68874","url":null,"abstract":"Several factors are reviewed for specifying and measuring the frequency vs. temperature (f-T) characteristics of precision quartz crystal oscillators. Topics include static vs. dynamic measurement, thermal time constant, activity dips, condensables, hysteresis, and trim effect. This work reviews some f-T considerations that are not discussed in detail in MIL-0-55310.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"31 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":"127558782","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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