LGS低相噪温度补偿振荡器的研究

发布时间：2018-06-29 19:55

本文选题：LGS + 温度补偿　；参考：《电子科技大学》2015年硕士论文

【摘要】：晶体振荡器,简称：晶振或晶片,被广泛的应用在电子通信技术领域,在未来的发展中,其越来越趋向于小型、薄片和片式化以及“三高两低”,即：高精确度、高稳定性、高频率,低功耗、低相噪。传统的晶体振荡器是谐振器件,它是根据SiO2结晶体(石英晶体)的压电效应制成的,由于石英晶体本身所具有的特性,在应用中存在较大的频温偏移,特别是一些高频高稳定度的场合,采用一般的温度补偿方式也不能很好的满足应用要求,所以寻找一种固有特性优于石英晶体的新型材料势在必行。本文在此基础上提出了一种在可调范围相对较优的新型材料,LGS:La3Ga5SiO14,langasite,简称LGS,对比分析了LGS和石英晶体的频温特性及其他相关特性,并比较了几种较为普遍的温度补偿方式,最后确定了晶振材料和补偿方案。经国内外众多科学家的反复研究,可知LGS晶体除了继承石英晶体材料较好的压电特性和温度稳定特性外,它还具有较石英晶体更大的机电耦合系数、更小的器件插入损耗以及更宽的带宽。另一方面,传统的微机温度补偿技术在硬件上并没有采用比较先进的处理器,导致处理器资源具有很大的局限性,不能实现复杂的补偿算法,而与处理器分离的测温单元、模数转换单元更会增加人工误差。在软件上缺乏相对完善的算法控制,使得每次实验都需要重启系统、下载程序,使得实验步骤和实验难度大大增加。随着计算机技术的飞速发展,嵌入式的应用越来越普遍,新型的嵌入式微处理器层出不穷,性能也越发强大,集成的片上资源也越来越丰富。本文选用的是STM32f103rc微处理器,它基于ARM公司的Cortex-M3核心,具有多个12位的A/D、D/A模块,丰富的硬件调试接口和外设I/O。结合一套小型的、稳定的、功能完善的国产开源嵌入式实时操作系统RT-thread实现在线实时控制功能,上位机端通过多种温度补偿算法择优计算出需要的补偿电压,这样就避免了程序的反复下载,大大减少了实验步骤,提高了系统的智能化程度,也在一定程度上减少了系统的误差。综上,本文采用新型的LGS晶体振荡器,结合比较先进的温度补偿系统进行研究,大大提高了精度,甚至可以满足某些对精度要求严格的场合。
[Abstract]:Crystal oscillators, or wafers, are widely used in the field of electronic communication technology. In the future, they tend to be more and more small, wafer and wafer, and "three high and two low", that is, high precision and high stability. High frequency, low power consumption, low phase noise. The traditional crystal oscillator is a resonator, which is based on the piezoelectric effect of Sio _ 2 crystal (quartz crystal). Because of the characteristics of quartz crystal itself, there is a large frequency temperature deviation in application. Especially in some high frequency and high stability cases, the general temperature compensation method can not meet the requirements of the application, so it is imperative to find a new material with better inherent properties than quartz crystal. In this paper, a new material, LGS: La3Ga5SiO14 langasiteLGS, which is relatively excellent in adjustable range, is proposed. The frequency and temperature characteristics of LGS and quartz crystals are compared and analyzed, and several common temperature compensation methods are compared. Finally, the crystal oscillator material and compensation scheme are determined. After repeated studies by many scientists at home and abroad, it is known that the LGS crystal not only inherits the better piezoelectric and temperature stability properties of quartz crystal, but also has a larger electromechanical coupling coefficient than quartz crystal. Smaller device insertion loss and wider bandwidth. On the other hand, the traditional microcomputer temperature compensation technology does not adopt the more advanced processor in the hardware, resulting in the processor resource has the very big limitation, cannot realize the complex compensation algorithm, but separate from the processor temperature measurement unit, The analog-to-digital conversion unit will increase the manual error. The lack of relatively perfect algorithm control in the software makes it necessary to restart the system and download the program for each experiment, which greatly increases the experimental steps and the difficulty of the experiment. With the rapid development of computer technology, embedded applications are becoming more and more common, new embedded microprocessors emerge in endlessly, the performance is more and more powerful, and the integrated on-chip resources are more and more abundant. In this paper, STM32f103rc microprocessor is selected, which is based on the Cortex-M3 core of arm Company. It has several 12-bit A / D / D / A modules, rich hardware debugging interface and peripheral I / O. Combining with a set of small, stable and perfect domestic open source embedded real-time operating system RT-thread, the on-line real-time control function is realized. The upper computer calculates the required compensation voltage through a variety of temperature compensation algorithms. In this way, the repeated downloading of the program is avoided, the experimental steps are greatly reduced, the intelligent degree of the system is improved, and the error of the system is reduced to a certain extent. In summary, a new type of LGS crystal oscillator and advanced temperature compensation system are used in this paper, which can greatly improve the precision and even meet the strict precision requirements in some occasions.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN752

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