Design Of Portable Multi-channel Electrogastrography Acquisition System And Research On Denoising Method Based On VMD

Electrogastrography(EGG)is a method that can assess stomach function.However,the existing EGG acquisition system has the problem of large volume,which cannot track the changes of gastric electricity in patients within a day and cannot meet the needs of daily monitoring.Due to the characteristics of EGG signal,the quality of EGG is still poor after processing,which is difficult to provide sufficient and effective diagnostic information.Therefore,EGG has not been widely used in clinical practice.This paper analyzed the design of the existing equipment,and proposed a multi-channel wireless miniature EGG acquisition system that can be used for daily monitoring.According to the characteristics of EGG signal,the system selected the 32-bit analog-to-digital converter ADS1263 to realize the design idea of DC low-amplification,and used digital high-pass filter to simplify the circuit design.Finally,the system volume was reduced to the size of a business card,which is easy to carry around and can work continuously for more than ten hours.At the same time,the host computer software with real-time display was developed,which can monitor the research object for a long time and display the waveform comparison of a specific area after processing.The prototype was made and compared with the MP150 system containing the EGG acquisition module in terms of the EGG signal of healthy human and the EGG signal of rabbit serosa.The results showed that the average correlation between the system and MP150 system could reach 0.87,which was a significant correlation,indicating the reliability of the system to collect the EGG signal.In terms of data analysis,this paper established a simulation model,and proposed a method of variational modal decomposition(VMD)combined with permutation entropy to determine the optimal decomposition parameters and automatically reconstruct the EGG signal.The improved VMD method and the other two decomposition methods were applied to the simulated EGG signal to compare the decomposition effect.The improved VMD method increased the correlation from 0.52 to 0.73.It showed that this method can effectively decompose the EGG signal into different components,and the reconstructed EGG signal is pure.Finally,the multi-channel EGG signals of 18 healthy subjects were collected in fasting and post-meal,and the real EGG signals were used to verify the decomposition effect of the improved VMD method.Then the time-frequency parameter analysis,the correlation and the phase-locked value analysis of multi-channel EGG data were analyzed.After the meal,the dominant frequency and amplitude of the EGG signal increased significantly,and the correlation and phase lock value of channels increased significantly.It showed that the parameters can reflect the information of gastric slow wave propagation,which lays the foundation for the subsequent study of patients with gastrointestinal dysfunction.In summary,this paper introduces the system design and data processing.The results show that the system can be used for daily monitoring of gastric electricity;the analysis results of multi-channel data can effectively distinguish between fasting and postprandial states.The results are expected to provide key support for the evaluation of gastric function health.