何朝博,滕云田,胡星星. 2021. 光泵磁力仪频率信号高精度测定技术实现. 地震学报,43(2):245−254. doi: 10.11939/jass.20200091
引用本文: 何朝博,滕云田,胡星星. 2021. 光泵磁力仪频率信号高精度测定技术实现. 地震学报,43(2):245−254. doi: 10.11939/jass.20200091
He Z B,Teng Y T,Hu X X. 2021. Realization of high-precision measurement technology for frequency signal of optically pumped magnetometer. Acta Seismologica Sinica43(2):245−254. doi: 10.11939/jass.20200091
Citation: He Z B,Teng Y T,Hu X X. 2021. Realization of high-precision measurement technology for frequency signal of optically pumped magnetometer. Acta Seismologica Sinica43(2):245−254. doi: 10.11939/jass.20200091

光泵磁力仪频率信号高精度测定技术实现

Realization of high-precision measurement technology for frequency signal of optically pumped magnetometer

  • 摘要: 针对井下弱磁观测环境狭小,测量精度要求高,但方便实时上传数据,可实现自动测量等特点,设计并制作了一种适用于井下绝对观测的氦光泵磁力仪单片机的频率计。频率计基于Cortex-M3内核的ARM芯片,通过定时器的外部时钟模式进行定时计数,在中断函数中进行计算,得到信号频率。多次实验后,为进一步提高测量精度,使用32 MHz有源温补晶振为芯片提供主频信号,提高了主频精度,减少程序对CPU的资源占用率。实验结果表明:频率计精度较高,满足项目需求。系统误差稳定,在840.70 kHz—1.96 MHz的弱磁测量范围内,误差均为1 Hz,易结合误差原因通过软件补偿实现高精度测量。

     

    Abstract: We designed and made a kind of microcontrollers frequency meter for borehole geomagnetic absolute observation by helium optically pumped magnetometer, which is suitable for the narrow space, high measurement accuracy, an easy access to upload data and automatic measurement. This frequency meter is based on ARM Cortex-M3 microcontroller, using timers’ external clock mode to count and calculate the frequency result in the interrupt service function. After many experiments, in order to further improve the measurement accuracy, the 32 MHz active temperature-compensated crystal oscillator is used to provide the main frequency signal for the chip, which improves the main frequency accuracy and reduces the code’s resource occupation rate of the CPU. The results show that the frequency meter has enough high precision that can meet the project requirements. The system error is stable, and the systemerror is 1 Hz in the range of 840.70 kHz to 1.96 MHz. Considering the specific reason for this error, we can easily compensate it by software codes and then realize a high-precision measurement.

     

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