基于磁敏电阻和复合调制的弱磁测量方法

摘要

针对磁敏电阻存在温度系数大和不能检测磁场方向的缺点,提出了基于直流复合调制和交流复合调制的弱磁测量新方法.设置两个空心线圈,其中之一与磁敏电阻串联并产生调制磁场,另一个产生参考磁场.对于直流调制,分别在有参考磁场和无参考磁场时改变调制磁场的极性,检测和处理磁敏电阻两端的直流电压,获得被测磁场的数值及其方向；对于交流调制,分别在有参考磁场和无参考磁场时检测和处理磁敏电阻两端的直流电压,获得被测磁场的数值及其方向.实验表明采用所提出的方法能够检测磁场方向,并且磁场测量结果与温度无关,证明了该方法的有效性.%Because of the large temperature coefficient and insensitiveness to the direction of the magnetic field, the magnetic resistor is unsuitable to directly measuring weak magnetic field. A novel method of weak magnetic field measurement is proposed in which the magnetic resistor and the DC/AC complex modulation are incorporated. Designed are two hollow coils, one is connected with the magnetic resistor in series to generate modulated magnetic field and the other generates the reference magnetic field. With the DC modulation, the polarity of the modulated magnetic field is changed alternatively in the cases that the reference magnetic field is applied or removed, then the DC voltages of the magnetic resistor are detected and processed, finally the amplitude and the direction of the magnetic field are obtained. With the AC modulation, the DC voltages of the magnetic resistor are detected and processed alternatively in the cases that the reference magnetic field is applied or removed, then the amplitude and the direction of the magnetic field are obtained. The effectiveness of the proposed method is verified by the experiments which prove both the ability of detecting the direction of magnetic field and the independence of the measurement results on the temperature.