###### Abstract  
Electrical impedance tomography (EIT) is an advanced visualization detection technique with non-invasive, radiationless, and fast-response characteristics. As an important means in dredging engineering, EIT-based measurement can realize the estimate and computation of key flow parameters such as the flow velocity and solid phase fraction of solid-liquid two-phase flow in a pipe. Despite progress, both the data acquisition rate and the signal-to-noise ratio (SNR) of the existing EIT system are too low to meet many practical requirements. In this study, efforts are made concerning the EIT acquisition system by optimizing the sensor array, data acquisition system, and data communication module. Experimental results show that (1) the optimized system has an SNR of 73 dB, which is about 40% higher than the original system, and (2) the optimization of data transmission methods can achieve a maximum allowable transmission rate of 316.4 Mbps, sufficient to support data transmission over 1000 frames per second. Consequently, the key problems of the existing EIT acquisition system are substantially overcome.  
electrical impedance tomography; data acquisition system; signal-to-noise ratio; data acquisition rate +
Footnote †: journal: Applied sciences  
system based on FPGA was introduced, with an SNR of 74 dB. They also presented an EIT hardware system based on a controller area network (CAN) bus, which expands the frequency of the excitation signal to 10 MHz [10]. Introducing the multi-period undersampling technique enables it to extract more imaginary part information of impedance. The existing EIT system has achieved certain real-time accuracy and has been applied in practical engineering [11]. Compared with traditional EIT devices, the EIT system in this article integrates three functions: flow measurement, solid phase content measurement, and visualization while possessing high measurement accuracy and real-time performance [12; 13].  
EIT has taken effects in estimating and measuring the key parameters in dredging engineering, but the low spatial resolution limits its in-depth and further applications. Essentially, two key problems remain unsolved as follows:  
1. Signal-to-noise rate (SNR): To ensure the accuracy of measurement data, higher requirements of SNR have been put forward. However, the existing EIT data acquisition system cannot keep a high SNR under arbitrary conditions. The acquisition and processing system of EIT must be improved;
2. Acquisition rate: There is still significant room for enhancing the real-time performance of the measurement system, and the length of a single measurement cycle directly affects the data quality between the measurement results and the distribution of the medium in the pipe. Improving the EIT acquisition rate is a significant prerequisite for ensuring the accuracy of measurement results.  
In this study, we propose an optimization EIT design by solving the two main problems in the existing EIT system. The SNR is improved by optimizing measurement circuits and data transmission characteristics. The EIT acquisition rate is improved by optimizing the analog-to-digital conversion module and data communication module. At the same time, the digital phase-sensitive demodulation technique is used to ensure the real-time performance of the EIT system. The simulation and real experimental results show that compared to traditional EIT systems, the proposed design in the study can greatly improve the SNR and data acquisition rate.