巨磁电阻传感器的低频噪声抑制

Suppression of low frequency noise of GMR sensors

介绍了巨磁电阻(GMR)传感器的噪声来源及噪声模型。测试GMR磁传感器在直流供电模式和交流激励直流偏置供电模式下的输出电压功率频谱。表明GMR传感器的1/f噪声在低频域上功率谱密度较大,是影响其低频分辨力和灵敏度的主要噪声。交流激励、直流偏置供电模式,能对GMR传感器进行高频调制,使其工作于高频。通过高通滤波滤除低频1/f噪声,能有效抑制其低频噪声,提高分辨率,实现纳特斯拉级弱磁场的高精度检测。

The noise source and model of GMR （giant magnetoresistance） sensors was introduced. Output voltage power spectrum of GMR sensor was tested, in power supply mode of AC oand AC excitingwith DC bias. It shows that the GMR sensor has higher power spectral density of 1/f noise at low-frequency domain, indicating the 1/f noise is the main one affecting the low-frequency resolution and sensitivity of GMR sensor. Power supply mode of AC exciting with DC bias can make a high-frequency modulation of GMR sensors and make it work in higher frequency. Low frequency noise can be effectively suppressed and resolution enhanced by eliminating 1/flow frequency noise with high-oass filter and resultantlv nrecise detection ofnT level weak magnetie field can be realized