Author + information
- 1Key Laboratory of Complex System Intelligent Control and Decision, School of Automation, Beijing Institute of Technology, Beijing, 100081, China
- 2Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
- 3Department of General Surgery, Chinese PLA General Hospital, Beijing, 100853, China
- 4Department of Cardiology Internal Medicine, Nanlou Branch of Chinese PLA General Hospital, Beijing, 100853, China
- 5Department of Clinical Medicine, NanKai University
To build a remote monitoring system of electrocardiograph (ECG) based on General Packet Radio Service (GPRS) and dynamic domain name system (DDNS).
In this study, we used the ECG signal processing circuit, STM32 microcontroller, SIM900A module and personal computer to build a set of remote ECG monitoring system. The ECG signal was amplified time by two amplifier circuits which used AD620 and OP1177 as operation amplifiers, and then was sampled by the A/D in the STM32 microcontroller. The coordinate correction method was used to correct R wave deviation derived in the process of ECG filtering and detection. On the basis of TCP/IP, the GPRS module was set to the transparent transmission mode, and the detection mark of transparent transmission was established to complete a stable and convenient transmission of the ECG signal. The front end server and the back end sever of the cloud medical service platform were connected through the TCP/IP protocol, and the back end server received the ECG signal via DDNS.
In the process of signal preprocess, Hilbert zero phase filter was used to eliminate various noise interference, which made the peaks and troughs of ECG signal obvious, and the stable region smooth to facilitate the subsequent QRS detection. The threshold method was used to remove the remaining burr with high frequency and small amplitude, which made the output signal in the smooth region smoother. The exact coordinates of R wave was obtained after the signal dealt with the threshold method was continued to deal with the four following steps, interval method, exclusion method, matching method, and coordinate correction method. The interval method was used to select the alternative positive and negative waves. The false value points were removed using the exclusion method, and T wave and P wave with big amplitude mistaken as R wave was removed by matching method.
ECG signal could be real time transmitted and received by Hilbert zero phase filter, threshold method, interval method, exclusion method, matching method, and coordinate correction method based on the remote monitoring system GPRS and DDNS built in this study.