【作者】 李磊；

【导师】 杨宏春； 张振友；

【作者基本信息】 电子科技大学 ， 工程硕士（专业学位）， 2019， 硕士

【摘要】 随着通讯技术的发展,电子设备在振动下工作的性能指标要求越来越高。石英晶体振荡器作为电子仪器设备的时钟频率源,受石英器件自身结构和工作原理的限制,在外部振动环境下更容易受到影响,影响电子设备的正常使用。因此晶体振荡器的抗振性能可以说是通信设备在振动环境下正常使用的性能短板,只有改善了这一指标,才有可能整体提高上述电子设备在振动环境下的稳定性和可靠性。另外随着近年来发达国家加强对军用和通信领域的技术封锁,具有高抗振性能的晶体振荡器被列入管制名录,制约了我国通讯技术的发展。因此,本文以研制出一款低G灵敏度恒温晶振为设计目标,展开相关工作。在研制低G灵敏度恒温晶振时,首先介绍了作为晶体振荡器中核心部件的晶体谐振器的原理及相关计算方法,讨论了恒温晶体振荡器的主振电路和控温系统。之后介绍了晶振G灵敏度的原理,通过推导得出G灵敏度的测量方法,介绍了一种提高评估准确性的计算方法,并编写软件实现了数据采集和G灵敏度的自动计算。在此基础上,分析了提高G灵敏度指标的几种方法,确定了产品的研发方向。晶体谐振器是晶体振荡器中最容易受到振动影响的器件,提高了晶体谐振器的抗振指标,可以从根本上改善晶振的抗振性能。通过计算对比两种基座的结构参数,选择抗振效果更好的TO基座;通过实验分析晶片的曲率与曲面中心偏离对G灵敏的影响,得出最优的凸面曲率和降低凸面中心偏离的方法;通过改进镀膜方式和镀膜速率,有利于提高晶片电极的对称性,降低晶体的G灵敏度。通过以上晶体设计优化,经过实验验证,发现晶振G灵敏度降低了3倍。振动隔离设计可以抑制外界振动的幅度,通过分析振动隔离的模型,并使用有限元方法对橡胶材料进行仿真,分析不同密度、杨氏模量和结构设计对减振效果的影响,设计了一款橡胶减振结构。通过振动相噪测试发现此结构在高频段具有减振效果。通过使用加速度传感器实时监测外界振动情况,经过单片机计算出反向补偿电压,加到晶振的压控端,实现振动补偿的效果。论文介绍了数字补偿设计的软件硬件设计与上位机采集程序,并验证了补偿效果。通过三个方面的工作,研制出一款在0Hz到2KHz下G灵敏度指标优于0.16ppb/g的恒温晶振,在500Hz到1kHz范围内G灵敏度指标优于0.02ppb/g,接近国际领先水平,实现了设计目标。更多还原

【Abstract】 With the development of modern communication technology,the higher performances of electronic devices products under vibration environment are required.As the clock frequency source of electronic equipment,quartz crystal oscillator is more susceptible to external vibration by the limited of structure and mechanical principle,which will affect the normal use of electronic equipment.Therefore,the g-sensitivity performance of the crystal oscillator is a short board for the normal use under vibration environment.The stability and reliability of the electronic device under vibration environment can be improved by reduce the g-sensitivity of crystal oscillator.In recent years,developed countries have strengthened the technical blockade on military and communication fields,crystal oscillators with excellent g-sensitivity performance have been placed on the regulatory list.It restricted the development of China’s communication technology.Therefore,this paper focuses on develop a low g-sensitivity crystal oscillator.During the development of low g-sensitivity crystal oscillator,first we introduced the principle and related calculation methods of crystal resonators.Then we talked about the main oscillator circuit and the temperature control system of the oscillator.After that,we introduced the principle of crystal g-sensitivity and deduced the measurement method of g-sensitivity.We introduced a calculation method with more evaluation accuracy,then writed software to collect data and calculate the g-sensitivity automatically.Based on these works,we presented the methods of improvement of g-sensitivityThe crystal resonator is the most susceptible part in the crystal oscillator under vibration environments.The improvement of the crystal resonator can improve the performance of the crystal oscillator fundamentally.First,we calculated the structural parameters of two bases,the calculation showed the TO base has better g-sensitivity.Second,we analyze the influence of the value of the curvature and the center deviation to g-sensitivity,after that,we choosed the best curvature and found better method to get better surface.Third,we had done some jobs on coating method and the coating rate to get better electrodes.After these improvements,the g-sensitivity of crystal oscillator decreased three times.The vibration isolation part can weaken the amplitude of external vibration.We analyzed the vibration isolation model,and simulation the rubber material wih finite element method.We designed one rubber vibration isolation structure by analyze the effect on g-sensitivity with different density,Young’s modulus and structural design.The phase noise test under vaberation found that this structure weaken the amplitude of external vibration in high frequency.We monitored the external vibration situation by using acceleration sensor and calculated the reverse compensation voltage by microcontroller.Then we added it to the VC part of the crystal oscillator to realize the vibration compensation effect.Through these three aspects of work,we designed a low g-sensitivity crystal oscillator.The g-sensitivity of this crystal oscillator is better than 0.16ppb/g in the range of 0 Hz to 2 kHz,and better than 0.02 ppb/g in the range of 500 Hz to 1 kHz.We achieved the goal and the performance of this crystal oscillator reached international level.更多还原