To improve the measurement precision of the proton magnetometer (PM), a multi-average multi-cycle frequency measurement (M-MFM) method using both rising and falling edge of square wave is proposed in this study. First, the M-MFM method using Rising-Falling edge of square wave is presented based on the multi-cycle frequency measurement (MFM) method, and the formula of frequency measurement is deduced. Then, the relative error of the proposed method is analyzed, and the proposed method is optimized by solving the minimum value of the relative error formula. Finally, the implementation process of the proposed method in STM32 is introduced. The experimental results of the frequency measurement demonstrate that the measurement precision for low SNR sine signals is significantly increased by the proposed method. The experimental results of the magnetic field measurement show that the sensitivity is about 0.11 nT/Hz1/2@0.25 Hz in the range of the geomagnetic field while the proposed method is adopted by the PM, which is better than that of the other methods and the commercial instruments.

中文翻译：

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用于个人健康监测的基于智能手机的物联网系统

为提高质子磁力计（PM）的测量精度，本研究提出了一种同时使用方波上升沿和下降沿的多平均多周期频率测量（M-MFM）方法。首先，在多周期频率测量(MFM)方法的基础上，提出了利用方波上升-下降沿的M-MFM方法，并推导了频率测量公式。然后，对所提方法的相对误差进行了分析，通过求解相对误差公式的最小值对所提方法进行了优化。最后介绍了所提方法在STM32中的实现过程。频率测量的实验结果表明，该方法显着提高了低信噪比正弦信号的测量精度。