| In ERT system, the electrical resistance measurement is the key issue on accuracy of measurement and quality of reconstructed image for the electrical resistance tomography system, and the study of small resistance measurement circuit is very important.electrical resistance tomography system requires real-time processing data, so the system requirements measurement circuit has higher data processing speed. This thesis studied ERT system circuit and the measurement data processing module. The general design rules are deduced by simulating circuit and optimizing parameters using PSPICE simulation software. The rules satisfy the imaging system in different application fields and more complicated industrial process automation monitoring.On the basis of predecessors’ research, this mainly completed the following work:1、The working mechanism of ERT system and overall ERT simulation research situation at home and abroad are analyzed. Several common simulation software of EDA are introduced, and the advantages and disadvantages of each simulation software is analyzed too.2、The differential amplifier circuit, phase sensitive demodulation circuit, band-pass filter and low pass filter design are simulated by PSPICE.The result is analyzed for each circuit module.3、The thesis focused on phase sensitive demodulation circuit, band-pass filter and low pass filter circuits and their parameters are optimized design. The experimental results show that the phase compensation method can be effectively improved the sensitivity of phase sensitive demodulation circuit, changed capacitance value can improve the filtering effect, and the appropriate value of resistance can improve the stability of the system.Experiments demonstrated that the correctness of designing circuit can be fast and conveniently judged by using PSPICE,and can choose the best design scheme to improve the quality of circuit design and optimizing circuit. The method of circuit design of electrical resistance tomography is provided. |
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