基于被动和主动降噪的光声光谱气体检测仪背景噪声控制技术  

Background Noise Control of Photoacoustic Spectroscopy Based on Passive and Active Noise Cancellation

作　　者：马凤翔 李康[3] 程登峰 朱峰 赵跃 MA Fengxiang;LI Kang;CHENG Dengfeng;ZHU Feng;ZHAO Yue(Electric Power Research Institute,State Grid Anhui Electric Power Co.,Ltd.,Hefei 230000,China;SF6 Gas Characteristic Analysis and Purification Technology Laboratory,State Grid Corporation of China,Hefei 230000,China;Institute of Electrical Engineering,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]国网安徽省电力有限公司电力科学研究院,合肥230000 [2]国家电网有限公司六氟化硫气体特性分析与净化处理技术实验室,合肥230000 [3]中国科学院电工研究所,北京100190

出　　处：《高电压技术》2023年第1期432-439,共8页High Voltage Engineering

基　　金：国家电网有限公司总部科技项目(521205190014)。

摘　　要：光声光谱技术通过检测微弱的声压信号来反演气体浓度,与仪器调制频率对应的相干噪声对仪器检测灵敏度具有重要影响。该文首先分析了斩波器机械噪声和环境噪声对光声光谱仪检测的影响,而后提出采用厚度为30 mm的蜜胺泡棉板隔离光声检测模块实现被动降噪。然后提出利用声波在空间的叠加干涉抵消原理,使噪声在声接收环节与主动噪声控制模块产生的主动声波进行叠加,实现光声池主动降噪。最后搭建噪声干扰模拟实验平台对提出措施的有效性进行验证,结果显示在调制频率为100 Hz和400 Hz两种条件下,提出的降噪技术均可降低外界相干噪声影响,光声光谱仪的检测能力在应用被动降噪技术后提升了0.4倍,而应用主动降噪+被动降噪技术后提升了2.4倍。该研究可为光声光谱仪开发中噪声抑制措施的选择提供指导。Photoacoustic spectroscopy obtains gas concentration by detecting weak sound pressure signal.The coherent noise corresponding to the modulation frequency of photoacoustic spectroscopy has an important impact on detection sensitivity.Firstly,the influence of chopper mechanical noise and environmental noise on detection of photoacoustic spectrometer is analyzed,and an approach using melamine foam board with a thickness of 30 mm to isolate the photoacoustic spectrometer to realize passive noise reduction is proposed.Then,using the principle of superimpososed interference cancellation of sound waves,the noise is superimposed with the active sound waves generated by the active noise control module in the sound receiving link,so as to realize the active noise reduction of photoacoustic cell.Finally,a noise interference simulation experimental platform is built to verify the effectiveness of the proposed measures.The results show that the proposed noise cancellation technology can reduce the impact of external coherent noise under the conditions of modulation frequency of 100 Hz and 400 Hz.The detection ability of photoacoustic spectroscopy is improved after using noise cancellation technology.It improved by 0.4 times for passive noise cancellation and 2.4 times for active noise+passive noise cancellation.The research in this paper can provide guidance for the selection of noise suppression measures in the development of photoacoustic spectroscopy.

关 键 词：主动降噪 被动降噪 光声光谱仪 相干噪声 相干抵消 

分 类 号：TB535[理学—物理]