A fluxgate is a device that has important applications in weak magnetic field measurements. Compared with the second harmonic mode, the orthogonal fundamental mode fluxgate exhibits a better performance in terms of lower noise and wider bandwidth, making it popular among researchers in this field. An amorphous wire is a vital part of any orthogonal fundamental mode fluxgate, and its excitation parameters determine the performance of the sensor (especially the noise level). For different structures and sizes of amorphous wires as probes, the optimal excitation parameters of orthogonal fundamental mode fluxgate are different. The conventional excitation module development scheme suffers from problems such as a complicated structure and low flexibility. To overcome these problems, a simple, compact, and effective excitation module is proposed, which is composed of a waveform generator, signal conditioning circuit, and voltage-controlled current source. Owing to the high flexibility, the frequency of the direct digital frequency synthesis is fully programmable. We tested the design performance indexes of key parameters, such as excitation signal waveform, amplitude, noise level, and bandwidth. The excitation current noise level is as low as 12.42 nA/sqrt (Hz) @ 20 kHz without Iac and 17.35 nA/sqrt (Hz) @ 20 kHz with Iac. The effective bandwidth of the alternating current output is 10–200 kHz. Moreover, a system test platform was developed, and this module was used to analyze the variation trend of the noise level of the fluxgate sensor under different excitation parameters (such as Iac, Idc, and excitation current frequency). It has been proved that the excitation module helps in effectively and quickly selecting the best excitation parameters to improve the performance of orthogonal fundamental mode fluxgates and shorten their development cycle.

中文翻译：

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正交基模磁通门传感器的激励模块

磁通门是一种在弱磁场测量中具有重要应用的设备。与二次谐波模式相比，正交基模磁通门在更低的噪声和更宽的带宽方面表现出更好的性能，使其受到该领域研究人员的欢迎。非晶线是任何正交基模磁通门的重要组成部分，其激励参数决定了传感器的性能（尤其是噪声水平）。对于不同结构和尺寸的非晶线作为探针，正交基模磁通门的最佳激励参数是不同的。传统的励磁模块开发方案存在结构复杂、灵活性低等问题。为了克服这些问题，提出了一种简单、紧凑且有效的励磁模块，它由波形发生器、信号调理电路和压控电流源组成。由于高度的灵活性，直接数字频率合成的频率是完全可编程的。我们测试了激励信号波形、幅度、噪声电平和带宽等关键参数的设计性能指标。激励电流噪声水平低至 12.42 nA / sqrt (Hz) @ 20 kHz 无 Iac 和 17.35 nA / sqrt (Hz) @ 20 kHz @ 20 kHz 有 Iac。交流输出的有效带宽为 10–200 kHz。此外，开发了系统测试平台，利用该模块分析了不同励磁参数（如Iac、Idc、励磁电流频率）下磁通门传感器噪声水平的变化趋势。