基于FPGA数字锁相实现的弹光调制测旋光技术研究

发布时间：2018-05-31 01:38

本文选题：旋光 + 弹光调制器　；参考：《中北大学》2017年硕士论文

【摘要】：随着科技的发展,物质的旋光性在食品安全、药物鉴别、医学、石油、化工等领域得到越来越广泛的应用,其中对旋光角的测量更是至关重要。由于弹光调制器高调制精度、宽光谱窗口、大视场角等优点,选用弹光调制器对信号进行调制,同时利用数字锁相解调技术获取旋光角。本文首先分析了旋光原理、弹光调制器工作原理以及数字锁相解调技术的原理,并根据斯托克斯参量和穆勒矩阵推导出基于弹光调制器测旋光的原理,然后搭建了测量旋光的光路系统。然后设计了以FPGA为核心的硬件电路,主要包括信号放大模块、A/D转换模块、串口通信模块以及光耦隔离模块等。在FPGA内部完成了基于DDS技术方波驱动信号的产生、放大电路放大倍数的控制、A/D采集时钟的控制和数字锁相算法,并搭建SOPC系统实现了Lab VIEW对FPGA的控制。其中,通过串口将数字锁相的乘累加数据传输到Lab VIEW中,在Lab VIEW中进行数据拼接,并最终在上位机中完成数据的分析和处理。同时,Lab VIEW还可以发送数据到FPGA中,对驱动方波信号的频率、放大电路的放大倍数以及乘累加的时间进行控制。最后,对硬件部分和软件部分分别进行了测试,搭建了旋光测量实验平台,并对不同浓度的葡萄糖溶液进行了旋光测量实验。实验结果表明本系统测量旋光角的灵敏度为0.00041°,最大相对偏差为2.78%,针对650nm入射激光葡萄糖溶液的比旋光率为31.0(°ml·g~(-1)·dm~(-1))。本系统具有灵敏度高、工作稳定、便于集成化设计等优势。
[Abstract]:With the development of science and technology, the optical activity of substances is more and more widely used in the fields of food safety, drug identification, medicine, petroleum and chemical industry, among which the measurement of optical rotation angle is more and more important. Because of the advantages of high modulation precision, wide spectral window and large field of view, the elastic-optical modulator is used to modulate the signal, and the digital phase-locked demodulation technique is used to obtain the optical rotation angle. In this paper, the principle of optical rotation, the working principle of elastic-optic modulator and the principle of digital phase-locked demodulation are analyzed, and based on Stokes parameter and Muller matrix, the principle of measuring optical rotation based on elastic-optical modulator is deduced. Then the optical circuit system for measuring optical rotation is set up. Then the hardware circuit with FPGA as the core is designed, which mainly includes signal amplification module, serial communication module and optocoupler isolation module, etc. The generation of square wave driving signal based on DDS technology, the control of amplification power of amplifying circuit and the control of A / D acquisition clock and digital phase-locked algorithm are completed in FPGA. The SOPC system is built to realize the control of Lab VIEW to FPGA. Among them, the multiplicative accumulative data of digital phase-locked is transmitted to Lab VIEW through serial port, and the data is spliced in Lab VIEW, and finally the data is analyzed and processed in the upper computer. At the same time, Lab VIEW can also send data to FPGA to control the frequency of the driving square wave signal, the magnification of the amplifier circuit and the time of multiplication and accumulation. Finally, the hardware part and the software part were tested, the optical rotation measurement platform was set up, and the optical rotation measurement experiments were carried out for glucose solution with different concentrations. The experimental results show that the sensitivity of the system is 0.00041 掳and the maximum relative deviation is 2.78. The specific optical rotation rate of the 650nm incident laser glucose solution is 31.0 (掳ml / g ~ (-1) DMC ~ (-1). The system has the advantages of high sensitivity, stable work and easy integrated design.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN761

【参考文献】