3种直流电源在电阻抗成像应用中的性能比较研究

目的：为电阻抗成像（EIT）硬件系统选择一种较优的直流电源。方法：在电池、线性稳压电源和开关稳压电源分别供电条件下,利用频谱分析仪E4408B分析直流电源和激励源的输出频谱,根据每种电源的杂散的数目、功率水平和激励源中的干扰的数目、功率水平,来推断3种电源对测量误差的影响;同时在3种电源分别供电条件下,用EIT系统进行数据采集,求3种电源在18个激励频率下的综合信噪比（signal-to-noise-ratio,SNR）,从而判断3种电源对测量误差的影响。结果：就3种电源分别供电下的激励源中的干扰的个数和功率水平而言,电池供电下的激励源中存在6个干扰,功率高达-78.25dBm;线性稳压电源供电下的激励源中存在6个干扰,功率高达-67.11dBm;开关稳压电源供电下的激励源中存在15个干扰,功率高达-35.83dBm。电池在18个激励频率下的综合信噪比高于线性电源,线性电源高于开关电源。结论：在3种电源中,电池供电方式是EIT较优的电源选择方案。

Comparison of Performances of Three Kinds of Direct Current Power Source in the Application of Electrical Impedance Tomography(EIT)

Objective To provide the hardware system of EIT with an excellent direct current（DC） power source. Methods The spectrums of the outputs of DC power source and the driving source were analyzed by means of Spectrum Analyzer- E4408B when EIT system was respectively powered by battery, linear power source and switching power source. Based on the numbers and power levels of the spurs of the three power sources and the numbers and power levels of the interferences within the driving source, the influence of the three power sources on the error of measuring was estimated. Meanwhile the EIT system did data acquisition, the overall signal-to-noise-ratio（SNR） of the three power sources at the 18 frequencies were calculated and the influence of the three power sources on the error of measuring was judged. Results With respect to the numbers and power levels of the interferences within the driving source when EIT was powered respectively by the three power sources, the battery output 6 interferences, the highest power of which achieved -78.25 dBm; the linear power source output 6 interferences, the highest power of which achieved -67.11 dBm; the switching power source output 15 interferences, the highest power of which achieved -35.83 dBm. The overall SNRs of the battery at the 18 driving frequencies were higher than that of the linear power source, and the overall SNRs of the linear power source were higher than that of the switching power source. Conclusion The power mode of battery is the best for the hardware of EIT among the three power sources.