Hardware Design Of Portable Electrocardiogram Monitoring System

For the accelerating pace, work pressure and the gradual ageing, cardiovascular disease has become one major disease that seriously threat to people's health. In China, people dead from cardiopathy has taken 44% of all, cardiopathy has been a familiar disease. Diagnosing and defending cardiopathy is a chief medical problem. Electrocardiogram monitor is used to detect the change of Electrocardiogram signal, and it is requisite to the prevention, diagnosis and treatment to heart diseases.There are some disadvantages of the Electrocardiogram monitor on market: big, expensive, high power consumption, un-portable for patients. These disadvantages restrict the application of the device. In this dissertation a portable Electrocardiogram monitor is designed, aiming to sample Electrocardiogram signal and detect the movements of heart precisely and exactly. It could provide assistant analysis as well, i.e. sustain diagnose and treatment effectively. This dissertation has included the following work:First, Electrocardiogram signal sampling circuit is designed, including 12 leads method, preamplifier circuit, to increase Common Mode Rejection Ratio and system stability. On the basis of modified traditional instrument amplifier consisting of three amplifiers, the device adds driven right leg circuit to improve the capability, to acquire weak bioelectricity signal. 0.03-100Hz filter is designed and optimized with parameter simulation to reject the low and high frequency noise.Second, a signal processing system is designed based on ARM9 series processor S3C2440A which is produced by Samsung and provide two kind of A/D converting model as sampling theorem acquired to obtain the Electrocardiogram data. designed multiple voltage output solution. The Electrocardiogram data is stored in Flash or SD card, and is displayed on LCD with characteristic parameters. Data is transmitted to PC by USB interface with touch panel setting the device parameter.Third, to obtain longer working time of portable instrument, the power decreasing of the device is discussed based on hardware and software simulation under Pspice. The relation of algorithm complexity and power consumption is researched and the optimized strategy is proposed.