便携式岩矿石样本电性测量仪信号发生器研制

Development of signal generator for portable electrical impedance analyzer for rock and ore specimens

对岩矿石样本进行电性测量,能够进一步约束地球物理探测数据的解释结果,进而提升矿产勘探的精度和准确度.为能对极低(10Ω级)还是极高阻抗(10 MΩ级)的岩矿石样本都能进行精确和有效测量,本团队自主设计了CannySIP测量系统.但该系统存在仪器较为笨重、功耗高、且测量过程较为繁琐的问题.为解决这些问题,本文以CannySIP测量系统小型化和便携化为驱动,设计一种小尺寸,低功耗的板卡级信号发生器.该信号发生器支持通过SPI总线发送频率控制字的方式来配置频率的输出,因此频率控制高效简单.本信号发生器设计了恒压和恒流两种工作模式.这两种工作模式都支持频率可任意配置,幅值可五档配置,其中恒压五档为10 V、1 V、100 mV、10 mV和1 mV,恒流五档为10 mA、1 mA、100μA、10μA和1μA.不管是恒压还是恒流,五个档位跨度均较宽,因此能很好地实现对极低或极高阻抗的岩矿石样本进行非失真激励.此外,本信号发生器的尺寸较小,接口标准统一,功耗较低,所以适合便携式岩矿石样本电性测量仪内部集成,以提供激励信号.

Conducting electrical impedance rock and ore specimens can further constrain the interpretation results of geophysical exploration data,thereby improving the accuracy and accuracy of mineral exploration.In order to accurately and effectively measure rock and ore specimen with both extremely low(10Ωlevel)or extremely high impedance(10 MΩlevel),our team independently designed the CannySIP measurement system.However,the system has some problems,such as heavy instrument,high power consumption,and cumbersome measurement process.In this paper,driven by the miniaturization and portability of CannySIP system,a small size and low power consumption of the board level signal generator is designed.The signal generator can configure frequency output by sending frequency control word through SPI bus,so frequency control is efficient and simple.Two operating modes of constant voltage and constant current are designed in this signal generator.Both modes support arbitrary frequency configuration and five-level amplitude configuration,among which the five-level of constant voltage are 10 V,1 V,100 mV,10 mV and 1 mV,and the five-level of constant current are 10 mA,1 mA,100μA,10μA and 1μA.The spans of the five-level of these two modes are very wide,so the non-distortion excitation signals on rock and ore specimens with very low or very high impedance can be well realized.In addition,the size of the signal generator is small,the interface standard is unified,and the power consumption is low,so it is very suitable for internal integration of the portable electrical impedance analyzer for rock and ore specimens to provide excitation signals.