PCG ECG Acquisition System Design And Signal Processing Research

The incidence of congenital heart disease is rising in our country. The incidence in2011increased by2.56times compared with2000. According to the "China Birth Defects Prevention Report2012" issued by the former Ministry of Health, the incidence of congenital heart disease in2011accounts for26.7%of all birth defects cases. PCG is of great value to the diagnosis of heart and related cardiovascular diseases. It is very significant to research a PCG and ECG acquisition device, using the modern signal method to process and analyse the pathological heart sound signals of congenital heart disease which can provide a diagnostic reference to the doctor.The main subject is the design of the acquisition system of PCG and ECG based on Lab VIEW, the preprocessing, time-frequency analysis, feature analysis of the PCG and ECG signal. Firstly, the design of PCG and ECG signal acquisition analog circuit is introduced in the acquisition system. Secondly, another branch of PCG signal was input to the audio amplifier to realize the auscultation of heart sounds in real time. Thirdly, this paper presents the design of ECG acquisition analog circuit. Lastly, the module which the signal is acquired, saved and displayed in real time is introduced. The preprocessing of heart sound and ECG signal include de-noising the ECG signal by the means of Wavelet, extracting the envelope of the heart sound signal by means of normalized average Shannon energy and using an algorithm for the segmentation of heart sound signal which not relying on the timing information of ECG signal. After the segmentation, the location of the first heart sound, second heart sound and the systolic and diastolic position can be identified. The characteristic analysis of heart sound signal includes the time-frequency analysis and the power spectrum estimation of the heart sound signal. The time-frequency anlysis of heart sound signal is to analyse the signal of the normal persons and patients with atrial septal defect using the time-frequency analytical method such as STFT, Choi-Williams distribution. Thus, we can obtain the different distribution of the signal in the time and frequencies domain between the normal persons and patients with atrial septal. Through the characteristic analysis of the heart sound signal mainly introduces the power spectrum of the heart sound signal of the normal persons and patients with atrial septal defect, we can achieve the difference of the distribution of the energy in frequency domain between the normal persons and patients with atrial septal defect.The acquisition system of heart sound and ECG signal has been used for acquiring the signal with congenital heart diseases. This device can work normally and acquire the signal accurately. Through the preprocessing, the featured analysis of the heart sound signal can provide a diagnostic reference to the doctor.