Design Of Cardic Reserve Monitoring System Based On Embedded System

In decades, the life styles of human beings have changed greatly along with the development of society.Cardiovascular disease has become the leading cause of death threat to humans. Heart sound is the reflection of cardiovascular system mechanical movement conditions. According to the relationship of heart sounds and cardiac contractility, Cardiac reserve status can be used as an auxiliary means for the evaluation of the state of heart, help to the prevention and treatment of cardiovascular disease. And with the constant progress of science and technology, especially the rapid development of microelectronics technology and signal processing technology, medical equipment has been gradually to develop in the direction of miniaturization.In view of this, this paper designs a set of cardiac reserve monitoring system based on embedded system, the system is easy to operate and portable for the convenience of special groups and healthy people to monitor their own heart health in real-time.First of all, in order to satisfy the need of the system we choose Samsung S3C2440 microprocessor as the core of the hardware system.This paper choose Linux system as the software core which is the optimation choice with the developing costs and portability taken into account,and use QT graphical interface design application program.And then according to the system total solution, build an embedded system development environment based on Linux, mainly including the establishment of a cross compiler, the Linux kernel cutting and compilation, the transplantation of the Linux kernel and QT source compilation and transplantation.Secondly, according to the system requirements, after understanding the importtance of driver and the three important basic data structure to implementation of driver, design and implement the ADC driver.Then compile the ADC driver into the kernel of Linux and transplant to the target machine to make it meet the needs of the project.Thirdly, a software program based on Qt is designed. This paper USES multi-thread and double buffer technology to realize the collection of heart sound and display the waveform. In order to extact the required indicators more accurately,filtering the signal should be the first step.For achieving this objective, a detailed analysis of process about Wave Shrink is needed, then according to the process design algorithm and realize it. The endpoints detection module is finished based on the principles of short-time energy and short-time zero crossing rate after pretreatment,in order to extract the three features(the ration of first heart sound amplitude to second heart sound amplitude, S1/S2; the ration of diastolic to systolic duration, D/S; heart rate, HR) of cardiac reserve.Finally, after the ADC driver test, the algorithm of wavelet filtering test, the algorithm of index extraction test and functional test, the results showed that the cardiac reserve monitoring based on embedded system can realize the basic functions and operate stably.