夏彬标^1,2, 邓云³, 林凌^1,2, 李刚^1,2, 廖和琴³, 吴晟³, 崔琳³
1.天津大学精密测试技术及仪器国家重点实验室, 天津 300072;2.天津大学生物医学信息检测与处理实验室, 天津 300072;3.国家海洋技术中心, 天津 300112

摘要:
溶解氧浓度检测在水产养殖和环境监测中具有重要的意义。本文提出了一种基于快速数字锁相的溶解氧检测优化设计，利用快速数字锁相算法与过采样技术，实现了荧光信号和调制信号的快速相位解调，并得到二者相位差，根据Stern-Volmer方程求出溶解氧浓度值。本文分析了调制频率对测量结果的影响，选择合适的调制频率用于测量，并利用最小二乘法对测量结果进行拟合，拟合后的确定系数R-square为0.999 25。实验数据表明，测量结果相对误差（RE）小于±1.5%，相对标准差（RSD）小于4%，稳定时间小于50 s。本文提出的优化设计不仅具有较高的测量精度，还简化了硬件设计，降低了成本。
关键词:溶解氧数字锁相荧光寿命相位检测
DOI：10.11759/hykx20191226003
分类号:X832
基金项目:国家重点研发计划项目（2016YFE0205700）；国家自然科学基金项目（51871067）

Optimized design of dissolved oxygen measurement based on fast digital lock-in
XIA Bin-biao^1,2, DENG Yun³, LIN Ling^1,2, LI Gang^1,2, LIAO He-qin³, WU Sheng³, CUI Lin³
1.State Key Laboratory of Precision Measurement Technology and Instrument, Tianjin University, Tianjin 300072, China;2.China and Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin University, Tianjin 300072, China;3.National Ocean Technology Center, Tianjin 300112, China
Abstract:
The detection of dissolved oxygen concentration has great significance in aquaculture and environmental monitoring. In this paper, we introduce an optimized design for the measurement of dissolved oxygen based on fast digital lock-in. Using a fast digital lock-in algorithm and oversampling technology, fast-phase demodulation of the signal is realized. First, the phase difference between the demodulated and modulated fluorescence signals is determined, and the dissolved oxygen concentration is calculated using the Stern-Volmer equation. We then analyze the influence of modulation frequency on the measurement results, select the appropriate modulation frequency for measurement, and use the least squares method to fit the measurement results. The coefficient of determination R-square for this study was 0.999 25. A comparison with experimental data revealed that the relative error of our proposed method was less than ±1.5%, the relative standard deviation was less than 4%, and the stabilization time was less than 50 s. The optimized design introduced here has high measurement accuracy while also simplifying the hardware design and reducing cost.
Key words:dissolved oxygendigital lock-influorescence lifetimephase detection





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