电子测量技术
電子測量技術
전자측량기술
ELECTRONIC MEASUREMENT TECHNOLOGY
2015年
8期
30-35
,共6页
微弱信号检测%相位可调%锁相放大器%相敏检波器%信噪比
微弱信號檢測%相位可調%鎖相放大器%相敏檢波器%信譟比
미약신호검측%상위가조%쇄상방대기%상민검파기%신조비
weak signal detection%phase adj ustable%lock-in amplifier%phase-sensitive detection%SNR
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60 dB,信号幅度在10μV~1 mV,并且混杂有噪声时检测误差不超过6%。
針對彊譟聲通信環境的微弱信號檢測問題,利用鎖相放大器技術將輸入的微弱信號與相位可變的參攷信號相榦解調濾波提取信號信息。繫統由信號預處理電路、參攷信號移相電路、相敏檢波電路、窄帶低通濾波器組成,其中參攷信號移相電路為相敏檢波電路提供相榦的參攷信號,相敏檢波電路將交流信號變為直流信號,窄帶低通濾波器去除寬帶譟聲,通過多次測量和最小二乘線性擬閤提高精度。該繫統信譟比 SNR增益大于60 dB,信號幅度在10μV~1 mV,併且混雜有譟聲時檢測誤差不超過6%。
침대강조성통신배경적미약신호검측문제,이용쇄상방대기기술장수입적미약신호여상위가변적삼고신호상간해조려파제취신호신식。계통유신호예처리전로、삼고신호이상전로、상민검파전로、착대저통려파기조성,기중삼고신호이상전로위상민검파전로제공상간적삼고신호,상민검파전로장교류신호변위직류신호,착대저통려파기거제관대조성,통과다차측량화최소이승선성의합제고정도。해계통신조비 SNR증익대우60 dB,신호폭도재10μV~1 mV,병차혼잡유조성시검측오차불초과6%。
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.
