非晶丝GMI磁传感器信号的小波分析

摘要

Traditional peak detecting method is impossible to detect actual signals when the signal-to-noise ratio (SNR) of the output of a giant magneto-impedance (GMI) probe is less than OdB. A novel method, therefore, is presented to detect weak signals from the probe, which are directly sent to digital signal processing system after signal conditioning and sampling. In this method, the characteristics of the weak signals are extracted by wavelet transform and the amplitudes determined by the correlation method. The simulation results indicate that the probe' s output signals with SNR = - 15dB can even be detected by the hybrid method mentioned above.%当非晶丝巨磁阻抗效应( Giant Magneto-Impedance,GMI)磁探头输出数据的信噪比小于0时,常规的峰值检波方法难以检出真实信号.为此,提出了一种新的微弱信号检测方法,将非晶丝GMI磁探头的输出信号经放大、滤波和采样之后直接送入数字信号处理系统,利用小波变换方法提取微弱信号的特征,并利用相关分析法确定信号的大小.仿真结果表明,采用小波变换和相关分析相结合的方法,可检出信噪比达到- 15dB时的弱磁信号.