【摘要】 在利用红外光谱技术进行工业检测的系统中,有用信息通常是淹没在强噪声背景中的微弱信号,因此可采用微弱信号检测技术中的锁相放大器来实现有用信号的提取。该文阐述了微弱信号检测的基本原理,比较了不同参考波形的优劣。设计运用AD630作为相关乘法器的锁相放大器,实现了在强噪声环境中有效地提取信号。测试结果表明,该电路结构简单,线性度高,信噪比得到改善可达62dB。更多还原

【Abstract】 In near infrared spectroscopy for detection of industry systems,the useful information weak signal is often submerged in strong background noise.The lock-in amplifier could be used by weak signal detection technology to achieve the extraction of useful signa1.Weak signal detection theory was described,and the outputs of the different reference signals were compared.A lock-in amplifier was designed using the AD630 as associated multiplier to extract the useful information in strong background noise.The test results indicated that the circuit structure was simple with high linearity of outputs,and the SNRI value was 62 dB.更多还原