【作者】 毕建峰；

【导师】 王珏；

【作者基本信息】 燕山大学 ， 测试计量技术及仪器， 2004， 硕士

【摘要】 本文综述了国内外桥梁监测技术的发展概况，在深入研究脉冲激光测距和光纤应变测试原理的基础上，针对单片机固有计数频率低、计数量化误差大和延时不固定等不足，结合CPLD计数频率高、延时小而固定和单片机控制功能强的优势，并采用模数转换技术设计计数量化误差测量电路，提出了基于激光脉冲时间测量法的光纤应变测量的方案。应变测量系统主要由光源、传感光纤、光电探测器和信号处理电路组成。在光学系统设计中为提高系统的精度采用了光纤定向耦合器实现光脉冲的循环；在光电转换单元上采用高精度温度补偿的APD偏置电路，减小了温度和暗电流带来的噪声干扰。信号处理部分是本文研究的关键，采用MCU+CPLD的设计方法和模数转换技术构成时间间隔测量单元的理论基础，其中用可在系统编程的CPLD计数器实现了对循环光脉冲的判断以开关计数，并提供计数量化误差测量电路相应的时序和控制信号，用斜坡电路和12位A/D转换电路完成对计数量化误差的测量，保证了系统的分辨率。在系统设计中，对组成光学系统和信号处理的每一个环节都进行了理论分析和元器件的优化选择，并对系统的有关部分进行了仿真实验分析，完成了系统性能评估。在完成系统设计和元件优化选择之后，选用不同长度的光纤，组成应变测量实验系统并进行了两组实验。实验结果表明，由于设计精心、方法合理，系统测量精度高，灵敏度大，分辨率达到预定目标，且能较好地适应不同的测量环境。更多还原

【Abstract】 Summarizing the development statement of monitoring technology for bridge, based on principle of pulse laser ranger detection and fiber-optic strain measurement, in view of the problem affected by single-chip inherent feature, integrating the goodness of CPLD device and single-chip, using A/D converter to measure the count quantization error, a strain measurement system is worked out.The above system chiefly consists of light source, optic fiber sensor, photo detector and signal processing circuit. In the design of optical system, to improve system precision, the fiber optic coupler is added to make a laser pulse circle; in the unit of photo detection, we make a high-precision temperature compensation APD bias circuit, which allows system to abate the noise caused by temperature changer and dark current. In signal processing circuit, the key of our study, based on methods of MCU+CPLD and A/D converter, a time interval measurement unit is done, in which an ISP CPLD counter is carried out to judge laser pulse for controlling counting and offering signal of time series and control, and a count quantization error measurement circuit which main ramp circuit and 12 bits A/D conversion circuit guarantees the resolution of system. During systematic design, as for each section of optical system and signal processing, theory analysis and the optimal selection of components are finished, on the basis of which the simulation in some relative parts of system is analyzed and the evaluation of systematic performances is completed. Thereafter with different length, stain measurement experiment setting is constructed, whereby two group experiments is carried out. The result of experiment shows that high precision, super sensitivity and target resolution have been achieved by elaborate design and rational method; furthermore the system possesses good adaptation to different measuring environment.更多还原