摘要
信噪比是光谱仪器尤其近红外光谱仪的关键指标之一.锁相放大器是一种可以从干扰极大的环境中分离出特定载波频率信号的放大器.本文提出采用跟踪滤波、同步积分、相敏检波器和高阶巴特奥斯低通滤波相联用的锁相放大器研制路线,对于参考通道脉冲信号采用数字式移相方法提高移相的精度和稳定性,该锁相放大器具有频率跟踪性好、能够有效抑制信号输入通道噪声而且易于集成,可提高系统灵敏度和改善信噪比.应用于近红外弱光谱信号测量实验中,测量结果表明信噪比提升明显.
Signal-to-noise ratio(SNR)is one o f the key parameters o f spectral instruments,especially near-infrared spectrometer.The lock-in amplifier is a kind o f amplifier which can separate the specific carrier frequency signal from the interference environment.In this paper,we introduce a phase-locked amplifier with tracking filter,synchronous integration,phase sensitive detector and high-order barthos low-pass filter.For reference channel pulse signal,digital phase-shifting method is used to improve the accuracy and stability o f phase-shifting.The amplifier has good frequency tracking,can effectively suppress the noise o f signal input channel and is easy to integrate,which can improve the system flexibility and SNR.The lock-in amplifier is applied to the near-infrared weak spectrum signal measurement experiment,and the measurement results show that the signal-to-noise ratio is significantly improved.
作者
郑志忠
杨忠
修连存
Zheng Zhizhong;Yang Zhong;Xiu Liancun(College of Automation Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 211100,China;Nanjing Center,China Geological Survey,Nanjing 210016,China;Jiangsu Sansheng Institute of Intelligent Spectral Sensing Co.,Ltd.,Nanjing 211135,China)
出处
《现代科学仪器》
2020年第2期5-10,共6页
Modern Scientific Instruments
基金
国家重大科学仪器设备开发专项(2012YQ050250)
国家重点研发计划课题(2016YFF0103602)。
