传统的直接电测量方法受1/f噪声限制,在低频处信号与噪声发生混叠,难以实现高水平低噪声测量.该文提出一种基于电/磁转换的海洋电场低噪声检测方法,将电信号转化为磁信号,通过微机械的方法将磁信号调制到高频,有效避开低频1/f噪声影响.设计一种实现电/磁转换功能的微机械结构,利用TMR电阻构成惠斯通电桥测量磁信号,实现海洋电场的高水平低噪声检测.仿真与实验结果在1 Hz处噪声分别达到1.16 nV/Hz√ 和1.41 nV/Hz√,优于传统电测量方案的噪声水平,验证该方法的有效性.%Limited by 1/f noise, traditional electrical measurement has difficulties in achieving high-level low noise characterization as a result of signal aliasing with noise at low frequency. In this article, a new weak marine signal low noise detection technique based on electric/magnetic conversion method was proposed. Electric signal was converted into magnetic signal, and then mod-ulated to high frequency through micromechanics, which could avoid the impact of low frequency 1/f noise. Structure based on electric/magnetic conversion was designed. TMR based Wheatstone bridge was used in magnetic signal measurement to realize marine signal's high-level characteriza-tion. The results of simulation and experiment show that the low frequency noise of this module can reach 1.16 nV/ Hz√ and 1.41 nV/ Hz√ at 1Hz respectively, which is better than normal low-noise pre-amplifier, illustrating the effectiveness of this magnetic measuring current model.
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