Design And Implementation Of High Speed And Multi-Channel ECG Acquisition And Transmission System

As the pace of social life continues to accelerate,people’s cardiovascular burden is often accidentally increased.The prevalence of heart disease has been increasing year by year,which is the best proof."Early prevention,early detection and early treatment"is a healthy concept advocated by all health organizations.For the diagnosis and treatment of cardiac diseases,ECG(electrocardiogram)has always been an important reference in medicine.Because the information of heart activity reflected by diverse leads is different,the ECG collected by multi-lead system contains more comprehensive information of heart activity,which can overcome the defect that singlelead system can only analyze one lead.Based on the above situation,to meet the needs of wearable intelligent health monitoring system,a high-speed multi-channel ECG acquisition and transmission system has been designed and implemented in this thesis.The system is composed of multi-channel ECG acquisition board and signal transmission control part.The multichannel ECG acquisition board takes the ADS 1298 produced by TI as the core component.By analyzing the internal registers of ADS1298,the front circuit and right leg drive modules are set up.Then the circuit schematic diagram and PCB layout of the acquisition board are designed by using Altium Designer,and the components used in the design are welded on the PCB board to form a complete multi-channel ECG acquisition board.The acquisition board can collect ECG from different parts of the body surface and output digitized ECG by SPI communication.The signal transmission control part is implemented with USB2XXX as the hardware platform.This hardware platform takes STM32F407 as the main chip and supports USB bus to switch to various communication protocols.Using USB2XXX can effectively redevelop SPI communication to achieve the purpose of data transmission to PC.The system implemented in this thesis can synchronously collect eight-channel differential ECG signals at 1KSPS.A scheme to connect multiple acquisition boards with daisy chain has also been proposed in this thesis,which is in order to increase the number of channels and can be used for surface high density ECG acquisition.In the experimental verification process,using the system implemented in this thesis to collect low-frequency sinusoidal signal and multi-channel ECG,and using four acquisition boards to test the daisy chain connection scheme proposed in this thesis.The experimental results show that the high-speed multi-channel ECG acquisition and transmission system can successfully synchronously acquire the signal and transmit the signal data to the PC,providing data files for subsequent processing work.Another part of the experimental results show that the multi-channel ECG signal acquisition board is scalable.Daisy chain connection mode can make multiple acquisition boards work at the same time,which provides a reference basis for increasing the number of acquisition channels in the future.All the experimental results show that the system meets the design requirements.