面向TDLAS气体传感系统的锁相放大技术研究
发布时间：2018-11-23 17:53
【摘要】：近年来,气体污染已经成了威胁人们身体健康的因素之一,加强气体监测力度的重要性不言而喻。可调谐半导体激光吸收光谱技术(Tunable Diode Laser Absorption Spectroscopy,TDLAS)拥有高分辨率,高灵敏度,因此在温室气体监测中得到广泛应用,其中的二次谐波检测技术在气体监测方面已经实现了快速高灵敏度的测量。在TDLAS气体检测中需要运用锁相放大技术对携带有气体浓度信息的微弱二次谐波信号进行提取。本文针对TDLAS气体传感系统设计了一款锁相放大器用来提取微弱二次谐波信号。首先介绍了基于TDLAS技术气体检测的相关原理,包括:红外光谱吸收原理,TDLAS技术原理,谐波检测原理以及数字锁相放大器原理,信号的相关检测原理。根据以上原理,利用System Generator建模,对数字锁相放大器的各个分模块进行设计,包括生成参考正交信号的DDS,乘法器和低通滤波器,对各个模块分别进行验证,使用设计的模块搭建了双通道的数字锁相放大器模型,并对其进行仿真和功能验证。其次,基于FPGA使用VHDL语言设计数字锁相放大器各部件,包括DDS模块,乘法器,分布式低通滤波器,开方模块等。对每个模块进行了仿真,在ISE中使用原理图的设计方法实现了双通道的数字锁相放大器的设计。最后,根据系统的需求选定了Spartan6系列XC6SLX45T型芯片作为我们系统的主芯片,并根据需求设计了锁相放大器的电路板,并把设计的双通道数字锁相放大器的代码下载到设计的电路板中,最后针对具体信号进行了测试,测试结果表明数字锁相放大器能够很好地提取待测信号的幅值并具有良好的稳定性。
[Abstract]:In recent years, gas pollution has become one of the factors threatening people's health, and the importance of gas monitoring is self-evident. Tunable semiconductor laser absorption spectroscopy (Tunable Diode Laser Absorption Spectroscopy,TDLAS) is widely used in greenhouse gas monitoring because of its high resolution and high sensitivity. Among them, the second harmonic detection technology has realized fast and high sensitivity measurement in gas monitoring. The weak second harmonic signal with gas concentration information should be extracted by phase-locked amplification technique in TDLAS gas detection. In this paper, a phase-locked amplifier is designed for TDLAS gas sensing system to extract weak second harmonic signal. Firstly, the related principles of gas detection based on TDLAS technology are introduced, including infrared spectrum absorption principle, TDLAS technology principle, harmonic detection principle, digital phase-locked amplifier principle and signal correlation detection principle. According to the above principle, using the System Generator modeling, each sub-module of the digital phase-locked amplifier is designed, including the DDS, multiplier and low-pass filter that generate the reference orthogonal signal, and each module is verified respectively. A dual channel digital phase-locked amplifier model is built with the designed module, and its simulation and function verification are carried out. Secondly, the digital phase-locked amplifier components are designed based on FPGA using VHDL language, including DDS module, multiplier, distributed low-pass filter, open-square module and so on. Each module is simulated, and the design of dual channel digital phase-locked amplifier is realized by using the schematic design method in ISE. Finally, according to the demand of the system, the Spartan6 series XC6SLX45T chip is selected as the main chip of our system, and the circuit board of the phase-locked amplifier is designed according to the demand. The code of the dual-channel digital phase-locked amplifier is downloaded to the designed circuit board. Finally, the specific signal is tested. The test results show that the digital phase-locked amplifier can extract the amplitude of the signal well and has good stability.
【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】：X84
本文编号：2352299
[Abstract]:In recent years, gas pollution has become one of the factors threatening people's health, and the importance of gas monitoring is self-evident. Tunable semiconductor laser absorption spectroscopy (Tunable Diode Laser Absorption Spectroscopy,TDLAS) is widely used in greenhouse gas monitoring because of its high resolution and high sensitivity. Among them, the second harmonic detection technology has realized fast and high sensitivity measurement in gas monitoring. The weak second harmonic signal with gas concentration information should be extracted by phase-locked amplification technique in TDLAS gas detection. In this paper, a phase-locked amplifier is designed for TDLAS gas sensing system to extract weak second harmonic signal. Firstly, the related principles of gas detection based on TDLAS technology are introduced, including infrared spectrum absorption principle, TDLAS technology principle, harmonic detection principle, digital phase-locked amplifier principle and signal correlation detection principle. According to the above principle, using the System Generator modeling, each sub-module of the digital phase-locked amplifier is designed, including the DDS, multiplier and low-pass filter that generate the reference orthogonal signal, and each module is verified respectively. A dual channel digital phase-locked amplifier model is built with the designed module, and its simulation and function verification are carried out. Secondly, the digital phase-locked amplifier components are designed based on FPGA using VHDL language, including DDS module, multiplier, distributed low-pass filter, open-square module and so on. Each module is simulated, and the design of dual channel digital phase-locked amplifier is realized by using the schematic design method in ISE. Finally, according to the demand of the system, the Spartan6 series XC6SLX45T chip is selected as the main chip of our system, and the circuit board of the phase-locked amplifier is designed according to the demand. The code of the dual-channel digital phase-locked amplifier is downloaded to the designed circuit board. Finally, the specific signal is tested. The test results show that the digital phase-locked amplifier can extract the amplitude of the signal well and has good stability.
【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】：X84
【参考文献】
相关期刊论文 前1条
1 王紫婷;郭海丽;;基于Matlab/Simulink的数字滤波器IP核的设计与实现[J];兰州交通大学学报;2008年03期
，本文编号：2352299
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