Research On Portable Digital Heart Sound Analyzing Appliance

Heart sounds auscultation is an important way of non-invasive examination of heart diseases. Regardless of the latest advances in imaging techniques, heart sound auscultation is still the first choice being done in cardio clinic. For centuries, acoustical stethoscope has been used to carry out auscultation process. Traditional stethoscope, however, has several drawbacks, which holds back the development of auscultation. Up to now, the system of heart sounds collecting and analyzing method is still quite immature. No electronic method has been applied in clinic.The paper has designed a kind of potable heart sound analyzing instrument based on embedded computer and has achieved the following functions: acquit heart sounds, capture and display current heart sound signals; manage patient information and data files, perform the spectrum and time analysis of the heart sounds; replay the shape and sound of heart sound signals, and review the previous recordings. The instrument, which is small, low-cost and convenient, can make dynamic custody and diagnose for those patients who can't make normal movement because of suffering from heart sound diseases This study provides some basic analysis methods and the analysis tool for clinic. And it also plays a basis role for the assistant diagnosis of the heart diseases. This study demonstrated that a LabVIEW-based medical virtual instrument provides a low-cost, reliable and flexible solution for data acquistion and analysis of the phonodiogram.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 make a heart sounds sensor;3)Design the analog signal processing circuit, digital processing circuit and the methods of signal processing, Such as∑?? modulating method;4)The software running on the embedded computer of PCM-5825;5)Develop the software with LabVIEW, which has the following functions: acquit heart sounds, capture and display current heart sound signals; manage patient information and data files, perform the spectrum and time analysis of the heart sounds; Two methods was designed to make orientation of heart sound, including using R waveform of ECG and Shannon;...