Jeng Jen-Tzong, Hsu Ting-Yu
Institute of Mechanical and Precision Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan.
Rev Sci Instrum. 2011 Mar;82(3):034701. doi: 10.1063/1.3560071.
The responsivity and the field noise characteristics of the giant magnetoresistance (GMR) magnetometer driven by an alternating magnetic field are investigated. The harmonic spectrum of the sensor voltage shows that only the odd harmonics of excitation frequency are sensitive to the external dc field. To cancel out the even harmonics, the dual-bridge GMR magnetometer with the balanced output is proposed. With the dual-bridge configuration, the field-to-voltage transfer coefficient is doubled and the field noise is reduced by a factor of 1.4. The minimum field noise is 7 nT∕√Hz at 1 Hz with the ac excitation power of 5.5 mW. The proposed sensor is suitable for the electronic compass application.
研究了由交变磁场驱动的巨磁阻（GMR）磁力计的响应度和场噪声特性。传感器电压的谐波频谱表明，只有激励频率的奇次谐波对外部直流磁场敏感。为了消除偶次谐波，提出了具有平衡输出的双桥GMR磁力计。采用双桥配置，场电压转换系数提高了一倍，场噪声降低了1.4倍。在交流激励功率为5.5 mW时，1 Hz处的最小场噪声为7 nT∕√Hz。所提出的传感器适用于电子罗盘应用。
