自适应校相的锁定放大器设计  

Design on lock-in amplifier of Adaptive correction phase

作　　者：阴欢欢 李飞[2] 严鑫[3] 

机构地区：[1]武汉大学珞珈学院电子信息科学系,武汉430064 [2]杭州电子科技大学通信工程学院,杭州310018 [3]重庆通信学院军事信息网络工程教研室,重庆400035

出　　处：《电子测量技术》2015年第8期30-35,共6页Electronic Measurement Technology

摘　　要：针对强噪声通信环境的微弱信号检测问题,利用锁相放大器技术将输入的微弱信号与相位可变的参考信号相干解调滤波提取信号信息。系统由信号预处理电路、参考信号移相电路、相敏检波电路、窄带低通滤波器组成,其中参考信号移相电路为相敏检波电路提供相干的参考信号,相敏检波电路将交流信号变为直流信号,窄带低通滤波器去除宽带噪声,通过多次测量和最小二乘线性拟合提高精度。该系统信噪比SNR增益大于60dB,信号幅度在10μV^1mV,并且混杂有噪声时检测误差不超过6%。For the complexity of the problem of weak signal detection under the communication environment,lock-in amplifier technique is used.The weak signal as input is for coherent reception with the phase reference signal that is adj ustable,the noise mixed with an AC signal is transformed into a narrowband DC signal.System consists of a signal pre-processing circuit,a reference signal phase-shifting circuit,a phase-sensitive detection circuit,the narrowband low-pass filter module.Wherein the reference signal phase shift circuitry provides the reference signal with the same frequency demodulation to improve the accuracy of phase-sensitive detection circuit AC signal into a DC signal,the narrowband low-pass filter is used to remove broadband noise,accuracy is improved by many times for phase-sensitive detection circuit measurement and least squares linear.This method ensure that the SNR is greater than 60 dB.when the signal magnitude within 10μV-1 mV,detection error does not exceed 6% when noise is mixed with.

关 键 词：微弱信号检测 相位可调 锁相放大器 相敏检波器 信噪比 

分 类 号：TN911.5[电子电信—通信与信息系统]