摘要
与谐波检测相结合的波长调制技术是目前检测有害气体的主要方法。主要是用实验的方法找到了甲烷气体在1 650 nm附近的一根吸收线,然后采用正弦信号对激光器的驱动进行了调制,实现了甲烷气体浓度的谐波检测。用锁相放大器RS830来提取二次谐波,然后根据锁相放大器的原理,用LabVIEW软件实现了锁相放大器的设计,来提取一次谐波信号,节约了成本。由气体吸收室中的GRIN透镜引起的标准具效应是影响检测灵敏度的主要原因,最后对该噪声和其他可能的影响进行了分析。
The wavelength modulation technology combined with harmonic detection is one of the main methods for deleterious gas detection. One of the methane absorption lines around 1 650 nm in the infrared areas is found mainly depending on experience, then a sine wave is used to modulate the laser driver in order to achieve the harmonic detection of methane gas concentration. The lock-in amplifier RS830 is used to detect the second harmonic signal. According to the fundamental of the lock-in amplifier, the function of lock-in amplifier is realized in LabVIEW software,used to detect the first harmonic signal, and the cost is reduced obviously. The interference noise caused by the GRIN lens in the gas absorption cell is the main reason for limiting the detection sensitivity, and is analyzed at last as well as other possible reasons.
出处
《仪表技术与传感器》
CSCD
北大核心
2007年第4期61-63,共3页
Instrument Technique and Sensor
基金
山西省工业攻关项目(051124-2)
山西留学归国人员重点基金(5210800)
山西省国际合作项目(200605005)
关键词
波长调制
谐波检测
甲烷
锁相放大
wavelength modulation
harmonic detection
methane
lock-in amplify
