The Development Of Heart Sounds Recording & Analyzing System

Heart disease is one of the main diseases that menace human's health. Heart sounds auscultation is an important way of non-invasive examination of heart diseases, Regardless of the latest advances in imaging techniques and electrocardiogram(ECG) auscultation is still the first routinely done cardiological examination. For centuries acoustical stethoscope has been used to carry out auscultation process. Traditional stethoscope, however, has several drawbacks, which holds back the development of medicine in auscultation. Up to now, the system of heart sounds collection and analyses is still quite immature, to some degree, only theory and study is carried out, it is almost blank of practical electronic medical manufactured product in heart sounds analyses and diagnosis.At first, the paper researches the mechanism of production and key property of heart sounds, analyses the drawbacks of acoustical stethoscope, concludes the existing conditions and existent deficiency in heart sounds collection and analyses at present. And according to Chongqing Hospital archiater's the specific requirements, demonstrates the feasibility of the heart sounds collection and analyses in theory. After that, the heart sounds collection and analysis system is developed with low cost to realize the real-time monitoring, the record and analysis of heart sounds applying a lot of subjects such as analog electronic technology, digital electronic technology, micro-controller and Visual C++.The main works in this paper are listed as follows:① Study on the basic knowledge of heart sounds, consists of the mechanism of production and key property of the first,the second,the third and the fourth heart sounds.② Analyzing the noises of heart sound collection and the characteristic of heart sound sensors, and bring forward the scheme to collect heart sounds. ③ design the analog signal processing circuit, consists of filter circuit, 50Hz rejector and amplification etc.④design the collecting circuit, consists of the A/D converter, the communication with PC, the key, LCD, D/A converter etc, in addition, design the heart sounds playback circuit. ⑤ Compile the program of microprocessor.⑥ Dispose the data collected by computer, and carry out digital filter and FFT conversion.⑦ program with Visual C++ based computer, consists of serial communication, multithread, the display and recording of data, etc.the mentioned work has been finished, and make an instrument using for experiment.