Research And Design Of Multi-channel Electrophysiological System Based On FPGA

Cardiac disease is a chronic and severe disease that has the feature of slow development and serious danger. Abnormal electrophysiological signal could refect the occurrence and development of heart disease. The doctor could judge the condition and development of cardiac disease from the unusual feature and distorted waveform in electrophysiological signal, and then gives appropriate diagnosis and treatment. So it is important to do the research and development of electrophysiological monitoring system.This thesis introduces one multi-channel electrophysiological system on FPGA (Field Programmable Gate Array), adopts morphological operation and Ethernet Protocol to filter ECG signal and send the electrophysiological signal, based on the characteristics of the ECG signal and the interference signal. The system implements acquisition and process of ECG signal, and makes doctors to do further research and analysis on the signal.The multi-channel electrophysiology system based on FPGA, which are data acquisition, data filtering and data transmitting are proposed in three aspects. The acquisition part collects multi-channel electrophysiological signal firstly, and then the collected signal is sent to signal processing circuit for preamplifier, band-pass filtering and post-amplifier, finally the processed signal is sent to A/D converter circuit for analog-to-digital conversion which is carried out under the control of FPGA. The filtering part uses morphological operation for extracting the feature of ECG signal and filtering the interference noise. According to the morphological theory the paper designs the mathematical morphology filter within two-layer structure, tests the ECG signal with baseline drift and power-line interface, and compares the test results. Assessment coefficient is proposed for verifying the performance of the filter. The transmitting part of the system adopts the method of Ethernet sending data and designs send module which had the function of controlling, counting and checking. At last the function simulation for various part of send module in FPGA is carried out.In this paper, multi-channel electrophysiology system is researched and designed from the processing of ECG signal. At first cache module is designed to deserialize data and complete sequential reading, which is based on the characteristics of multi-channel ECG signal in acquisition. Secondly two-layer structure of morphological filter is proposed to remove baseline drift and power-line interference after comparison with other filtering methods. At last the send module in FPGA is implemented to realize the transmitting function for ECG data through one chip and replaced the DSP chip in original system which achieved sending function.