Synthetic samples in the alpha phase at 550 degrees C and in the beta phase at 650 degrees C were studied with air and vacuum atmosphere and Pt foil electrodes. The electrical current variation was measured both during sweeping and final cooling, giving activation energies in the alpha and beta phase. The samples were characterized by IR measurements at 77 K: a complete disappearance of the OH lines was observed after vacuum sweeping in the alpha phase (550 degrees C-3500 V/cm) or in the beta phase (650 degrees C-1500 V/cm). Considerable modification of the birefringence variations within the incommensurate phase was found. Samples that are heated in the beta phase become twinned; however, a torque can detwin the major part of a AT-cut twinned sample.<>
{"title":"Study of quartz sweeping in alpha and beta phases","authors":"J.P. Balchheimer, G. Dolino","doi":"10.1109/FREQ.1989.68911","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68911","url":null,"abstract":"Synthetic samples in the alpha phase at 550 degrees C and in the beta phase at 650 degrees C were studied with air and vacuum atmosphere and Pt foil electrodes. The electrical current variation was measured both during sweeping and final cooling, giving activation energies in the alpha and beta phase. The samples were characterized by IR measurements at 77 K: a complete disappearance of the OH lines was observed after vacuum sweeping in the alpha phase (550 degrees C-3500 V/cm) or in the beta phase (650 degrees C-1500 V/cm). Considerable modification of the birefringence variations within the incommensurate phase was found. Samples that are heated in the beta phase become twinned; however, a torque can detwin the major part of a AT-cut twinned sample.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"71 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":"117086785","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}
Experimental results are presented demonstrating that plasma-assisted chemical etching (PACE) can rapidly and controllably figure (shape) and smooth optical surfaces without mechanical contact. This process, for example, significantly reduces the constraints on the design of quartz optical elements imposed by mechanical processes, such as the requirement of substrate rigidity and the limitation of sphericity of the resulting surface. The pertinent chemistry and physics of this process is summarized to provide a basis for understanding its characteristics. A theory of surface evolution applicable to PACE is used to show the range of surface topographies predicted for PACE. It is shown, among other things, that both isotropic and anisotropic etch processes intrinsically microsmooth features smaller than 0.1 mm, and that removal smooths while deposition roughens.<>
{"title":"Rapid, noncontact, damage free shaping of optical and other surfaces with plasma assisted chemical etching","authors":"C. Zarowin, L. D. Bollinger","doi":"10.1109/FREQ.1989.68924","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68924","url":null,"abstract":"Experimental results are presented demonstrating that plasma-assisted chemical etching (PACE) can rapidly and controllably figure (shape) and smooth optical surfaces without mechanical contact. This process, for example, significantly reduces the constraints on the design of quartz optical elements imposed by mechanical processes, such as the requirement of substrate rigidity and the limitation of sphericity of the resulting surface. The pertinent chemistry and physics of this process is summarized to provide a basis for understanding its characteristics. A theory of surface evolution applicable to PACE is used to show the range of surface topographies predicted for PACE. It is shown, among other things, that both isotropic and anisotropic etch processes intrinsically microsmooth features smaller than 0.1 mm, and that removal smooths while deposition roughens.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"237 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":"115844874","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 spectral performance of two types of analog dividers: a parametric divider using varactor diodes, and a regenerative-type divider incorporating a double balanced mixer in the oscillator feedback circuit. Both dividers were configured for divide-by-two operation at VHF. The parametric divider typically requires a moderately high input drive level and operates over relatively narrow bandwidth owing to the nature of the circuit constraints for generation of negative resistance at the output frequency =f/sub in2/. Prototype dividers were constructed utilizing abrupt junction varactor diodes and were designed without the need for the critical tuning or the input and output trap circuits normally used. At the specified 20 dBm drive, 6 dB conversion loss was obtained. Lowest 1/f noise was obtained with the varactor biased to insure nonconduction over the entire cycle of the RF waveform. Unlike the parametric divider, a regenerative-type divider can be operated over a wide range of drive levels and over a much wider bandwidth. The use of the regenerative-type divider appears especially attractive because it provides low 1/f noise and noise floor performance.<>
{"title":"Phase noise performance of analog frequency dividers","authors":"M. Driscoll","doi":"10.1109/FREQ.1989.68888","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68888","url":null,"abstract":"Measurements are reported of the spectral performance of two types of analog dividers: a parametric divider using varactor diodes, and a regenerative-type divider incorporating a double balanced mixer in the oscillator feedback circuit. Both dividers were configured for divide-by-two operation at VHF. The parametric divider typically requires a moderately high input drive level and operates over relatively narrow bandwidth owing to the nature of the circuit constraints for generation of negative resistance at the output frequency =f/sub in2/. Prototype dividers were constructed utilizing abrupt junction varactor diodes and were designed without the need for the critical tuning or the input and output trap circuits normally used. At the specified 20 dBm drive, 6 dB conversion loss was obtained. Lowest 1/f noise was obtained with the varactor biased to insure nonconduction over the entire cycle of the RF waveform. Unlike the parametric divider, a regenerative-type divider can be operated over a wide range of drive levels and over a much wider bandwidth. The use of the regenerative-type divider appears especially attractive because it provides low 1/f noise and noise floor performance.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"352 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":"115163516","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}
Various methods of determining electrode mass loading are presented, and measurements of mass loading using several of these techniques are compared. Variations between the values of mass loading obtained by the different techniques are discussed and a model is proposed to explain the differences. A simple first approximation to the effects of lateral boundedness which provides qualitative insights as to the cause of the variations is presented.<>
{"title":"Mass loading measurements of quartz crystal plates","authors":"J. Kosiński, S. Mallikarjun, A. Ballato","doi":"10.1109/FREQ.1989.68891","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68891","url":null,"abstract":"Various methods of determining electrode mass loading are presented, and measurements of mass loading using several of these techniques are compared. Variations between the values of mass loading obtained by the different techniques are discussed and a model is proposed to explain the differences. A simple first approximation to the effects of lateral boundedness which provides qualitative insights as to the cause of the variations is presented.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"147 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":"124707634","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 co-planar temperature-controlled crystal oscillator (CPXO) for precision frequency generation is described. All of the oscillator and temperature-control electronics are contained on one double-sided beryllium oxide substrate. This construction allows a more accurate control of crystal temperature than the classical ovenized approach. At the same time, the package size is reduced by eliminating the need for a separate oven. Smaller heated mass combined with greatly shortened thermal paths results in much shortened warmup time. Smaller surface area results in a reduced need for heater power to sustain operating temperature. These advantages of the CPXO are obtained without sacrificing the desirable features of the much larger ovenized crystal oscillator.<>
{"title":"A temperature-controlled crystal oscillator","authors":"L. Hurley","doi":"10.1109/FREQ.1989.68835","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68835","url":null,"abstract":"A co-planar temperature-controlled crystal oscillator (CPXO) for precision frequency generation is described. All of the oscillator and temperature-control electronics are contained on one double-sided beryllium oxide substrate. This construction allows a more accurate control of crystal temperature than the classical ovenized approach. At the same time, the package size is reduced by eliminating the need for a separate oven. Smaller heated mass combined with greatly shortened thermal paths results in much shortened warmup time. Smaller surface area results in a reduced need for heater power to sustain operating temperature. These advantages of the CPXO are obtained without sacrificing the desirable features of the much larger ovenized crystal oscillator.<<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":"122551445","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 distinction is shown between characterizing a complete oscillator, and characterizing only the quartz resonator by using a passive phase bridge. Advantages and disadvantages of the two approaches are discussed. Then measurements of temperature sensitivities, including quasistatic or dynamic thermal conditions are presented. One important points how to measure the real temperature of the device under test (quartz crystal for instance) rather than the temperature of the probe. Methods for measuring acceleration and pressure sensitivities are presented taking spurious effects of temperature changes into consideration. Various problems are discussed in connection with the measurement of the sensitivity to magnetic fields and electric fields.<>
{"title":"Characterization methods for the sensitivity of quartz oscillators to the environment","authors":"J. Gagnepain","doi":"10.1109/FREQ.1989.68872","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68872","url":null,"abstract":"The distinction is shown between characterizing a complete oscillator, and characterizing only the quartz resonator by using a passive phase bridge. Advantages and disadvantages of the two approaches are discussed. Then measurements of temperature sensitivities, including quasistatic or dynamic thermal conditions are presented. One important points how to measure the real temperature of the device under test (quartz crystal for instance) rather than the temperature of the probe. Methods for measuring acceleration and pressure sensitivities are presented taking spurious effects of temperature changes into consideration. Various problems are discussed in connection with the measurement of the sensitivity to magnetic fields and electric fields.<<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":"129584962","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}
Accurate calculations are performed of atomic trajectories in conventional cesium beam tubes (CBTs) using dispersive, two-wire field magnets and also in a novel configuration using two orthogonal one-dimensional focusing dipoles of the type described by P. Kartaschoff (1969). In the first configuration, it was possible to explain observed differences in atomic velocity distribution in terms of small variations in oven and/or detector offsets. The second configuration yields beam intensities that are significantly higher than the ones obtained with dispersive magnets and/or substantially lower atomic velocities, and thus could improve the frequency stability of compact cesium clocks in the white-noise regime. Present design differs from P. Kartaschoff's prescription in that a one-dimensional focussing dipole, rather than a hexapole or quadrupole magnet, is used as the A magnet in the CBT, making the tube manufacturing simpler.<>
{"title":"Atomic trajectories in compact cesium beam clocks","authors":"B. Jaduszliwer","doi":"10.1109/FREQ.1989.68860","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68860","url":null,"abstract":"Accurate calculations are performed of atomic trajectories in conventional cesium beam tubes (CBTs) using dispersive, two-wire field magnets and also in a novel configuration using two orthogonal one-dimensional focusing dipoles of the type described by P. Kartaschoff (1969). In the first configuration, it was possible to explain observed differences in atomic velocity distribution in terms of small variations in oven and/or detector offsets. The second configuration yields beam intensities that are significantly higher than the ones obtained with dispersive magnets and/or substantially lower atomic velocities, and thus could improve the frequency stability of compact cesium clocks in the white-noise regime. Present design differs from P. Kartaschoff's prescription in that a one-dimensional focussing dipole, rather than a hexapole or quadrupole magnet, is used as the A magnet in the CBT, making the tube manufacturing simpler.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"154 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":"124522248","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 methods used by CEPE in following areas are presented: g sensibility dynamic test (spectrum analysis of phase fluctuation under known random vibrations); acoustic sensitivity (spectrum analysis of phase fluctuation under known acoustic excitation); power supply sensitivity (spectrum analysis of phase fluctuation with ripple on power supply); barometric (pressure) sensitivity; and magnetic field sensitivity. Description of test equipments and procedures of these various measurements are given. Typical results (including reproducibility) are presented.<>
{"title":"Experimental procedure applied to characterize crystal oscillator under functional environment","authors":"G. Robichon, A. Debaisieux, J. Aubry","doi":"10.1109/FREQ.1989.68873","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68873","url":null,"abstract":"The methods used by CEPE in following areas are presented: g sensibility dynamic test (spectrum analysis of phase fluctuation under known random vibrations); acoustic sensitivity (spectrum analysis of phase fluctuation under known acoustic excitation); power supply sensitivity (spectrum analysis of phase fluctuation with ripple on power supply); barometric (pressure) sensitivity; and magnetic field sensitivity. Description of test equipments and procedures of these various measurements are given. Typical results (including reproducibility) are presented.<<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":"122484522","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}
Experimental determination is reported of the relationship among baffle design, the temperature difference between the growing and dissolving chambers, and the power requirements. Increasing the opening of the baffle requires a higher power level to maintain a given temperature difference. The presence of lascas or grown crystals, and the type of baffle used, have strong effects on the temperature difference-power curve. Growing-chamber temperature and top insulation have only minor effects.<>
{"title":"Experimental determination of the relationship among baffle, temperature difference and power for the hydrothermal growth of quartz","authors":"G. Johnson, R. Irvine, J.W. Foise","doi":"10.1109/FREQ.1989.68903","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68903","url":null,"abstract":"Experimental determination is reported of the relationship among baffle design, the temperature difference between the growing and dissolving chambers, and the power requirements. Increasing the opening of the baffle requires a higher power level to maintain a given temperature difference. The presence of lascas or grown crystals, and the type of baffle used, have strong effects on the temperature difference-power curve. Growing-chamber temperature and top insulation have only minor effects.<<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":"121033951","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}
Recent investigations on the magnetic sensitivity of certain on-board quartz crystal oscillators are presented. A part of the study deals with the global magnetic sensitivity of the devices as a function of the magnetic field intensity and direction. Measurements were done on various ovened oscillators used in actual satellites. In addition, in order to determine the origin of the magnetically induced frequency shift, some components were separated from the oscillator and individually submitted to the magnetic field. The work presents the experimental setup, measurement procedures and results obtained at the CNRS laboratory in Besancon. Special attention is paid to the quartz crystal resonator itself. It is shown to have a sensitivity on the order of 10/sup -12//G. An explanation of the resonator's magnetic sensitivity is given, and related verification experiments are presented.<>
{"title":"Influence of magnetic field on quartz crystal oscillators","authors":"R. Brendel, C. El Hassani, M. Brunet, E. Robert","doi":"10.1109/FREQ.1989.68877","DOIUrl":"https://doi.org/10.1109/FREQ.1989.68877","url":null,"abstract":"Recent investigations on the magnetic sensitivity of certain on-board quartz crystal oscillators are presented. A part of the study deals with the global magnetic sensitivity of the devices as a function of the magnetic field intensity and direction. Measurements were done on various ovened oscillators used in actual satellites. In addition, in order to determine the origin of the magnetically induced frequency shift, some components were separated from the oscillator and individually submitted to the magnetic field. The work presents the experimental setup, measurement procedures and results obtained at the CNRS laboratory in Besancon. Special attention is paid to the quartz crystal resonator itself. It is shown to have a sensitivity on the order of 10/sup -12//G. An explanation of the resonator's magnetic sensitivity is given, and related verification experiments are presented.<<ETX>>","PeriodicalId":294361,"journal":{"name":"Proceedings of the 43rd Annual Symposium on Frequency Control","volume":"62 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":"126424683","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：