A Portable Analog Lock-In Amplifier for Accurate Phase Measurement and Application in High-Precision Optical Oxygen Concentration Detection

• 作者: Fupeng WANG Jun CHANG Wei WEI Xi CHEN Yuanyuan LIU Zengguang QIN Zongliang WANG
• 来源期刊: 光子传感器:英文版
• 关键词: Portable analog lock-in amplifier phase shift measurement high accuracy optical oxygen detection
• 年，卷（期）: 2017,（1）
• 页码范围: 27-36
• 页数: 10页
• 分类号: YTP
• 语种: 中文

摘要

A portable analog lock-in amplifier capable of accurate phase detection is proposed in this paper. The proposed lock-in amplifier, which uses the dual-channel orthometric signals as the references to build the xy coordinate system, can detect the relative phase between the input and x-axis based on trigonometric function. The sensitivity of the phase measurement reaches 0.014degree, and a detection precision of 0.1 degree is achieved. At the same time, the performance of the lock-in amplifier is verified in the high precision optical oxygen concentration detection. Experimental results reveal that the portable analog lock-in amplifier is accurate for phase detection applications. In the oxygen sensing experiments, 0.058% oxygen concentration resulted in 0.1 degree phase shift detected by the lock-in amplifier precisely. In addition, the lock-in amplifier is small and economical compared with the commercial lock-in equipments, so it can be easily integrated in many portable devices for industrial applications.