摘要
本文基于可编程逻辑门阵列(field programmable gate array,FPGA)快速处理数字信号及多线程优势,结合波长调制可调谐半导体激光吸收光谱(WM-TDLAS)技术,研制可编程门阵列WM-TDLAS二氧化碳浓度检测系统。根据应用功能需求,利用FPGA芯片的逻辑门阵列可编程特性,设计了具备信号采集及调制、谐波解调功能的数字化锁相放大器(digital lock-in amplifier,DLIA)。为验证其性能进行谐波提取测试、Q值、抗噪声实验,结果表明目标频率提取线性度达99.99%,Q值可达45。在对不同信噪比信号进行谐波提取实验中,当信噪比为43 dB时,均值最大相对误差仅为0.91%。采用中心波长1572 nm分布式反馈激光器作为光源,覆盖选定的6360 cm−1处吸收线,密集多通气体吸收池有效光程14 m,开展了气体浓度检测实验。系统检测浓度与二次谐波幅值拟合线性度为99.982%,通过提升扫描波长频率,系统可在0.1 s获取浓度值。艾伦(Allan)方差结果表明,当积分时间为44 s时,系统的检测下限为1.86 ppm。实验结果表明,该可编程门阵列WM-TDLAS检测系统具有检测精度高、响应速度快、稳定性强和小型化的特点,可用于实际应用中浓度实时监测。
An FPGA-based field programmable gate array(FPGA)and wavelength-modulated tunable diode laser absorption spectroscopy(WM-TDLAS)technique have been combined to develop a programmable gate array WM-TDLAS CO_(2) concentration detection system.Leveraging the programmable nature of FPGA chips,a digital lock-in amplifier(DLIA)with signal acquisition and modulation,as well as harmonic demodulation functions,was designed to meet the application requirements.To validate its performance,harmonic extraction tests,Q-factor assessments,and anti-noise experiments were conducted.The results revealed a linearity of 99.99%for the target frequency extraction and a Q-factor of up to 45.In the harmonic extraction experiments for signals with different signal-to-noise ratios,the maximum relative error in the mean value was only 0.91%when the signal-to-noise ratio was 43 dB.Using a distributed feedback laser with a center wavelength of 1572 nm as the light source,covering the absorption line at 6360 cm−1,and utilizing an effective optical path of 14 m in a dense multi-pass gas absorption cell,gas concentration detection experiments were carried out.The system demonstrated a fitting linearity of 99.982% between the detected concentration and the amplitude of the second harmonic.By increasing the scanning wavelength frequency,the system was capable of obtaining concentration values in 0.1 seconds.The Allan variance results showed that the detection limit of the system was 1.86 ppm when the integration time was 44 seconds.The experimental results indicate that the developed WM-TDLAS detection system based on an FPGA array features high detection accuracy,rapid response,strong stability,and miniaturization,making it suitable for real-time concentration monitoring in practical applications.
作者
张鑫
邱海峰
兰嘉琪
胡琴
张贺
Zhang Xin;Qiu Haifeng;Lan Jiaqi;Hu Qin;Zhang He(State Key Laboratory of High Power Semiconductor Laser,Changchun University of Technology,Changchun,Jilin 130022,China)
出处
《光电工程》
CAS
CSCD
北大核心
2024年第4期77-86,共10页
Opto-Electronic Engineering
基金
吉林省教育厅科学技术研究项目(JJKH20240916)。
关键词
光谱学
可编程逻辑门阵列
波长调制光谱
数字锁相放大器
气体检测
spectroscopy
programmable gate array
wavelength modulation spectrum
digital lock-in amplifier
gas detection
