Heart Sound Signal Acquisition System Research And Design Based On ZigBee Networks

Heart sound signal is vibration generated when the systolic and diastolic heart sounds, is the heart and cardiovascular system to reflect the status of systolic and diastolic, which contains information on the physiological and physical interaction between itself and the various parts of the heart. At present, the traditional heart sound signal acquisition can not accurately capture the patient’s heart sounds of everyday life in real-time situations. Based on the former proposed wireless heart sound detection system based on Zig Bee protocol, the system can be anywhere on the heart sound signal acquisition and processing, and wireless transceivers. And the system is also at low power conditions to expand the detection range, to be detected by the full freedom and relaxation to obtain a more accurate real heart sound signals.This design using Zig Bee wireless communication technology for architecture, and contains some of the characteristics of heart sound signal preprocessing and collect heart sound signal analysis section. Collecting part is divided into hardware design and software design, mainly divided into the following modules: measuring physiological parameters extracted from the detection module, digital signal conditioning module conversion, wireless network signal transmission module, signal preliminary data analysis module, communication module and rear User information management module. By using the system on a chip(So C) CC2430 complete wireless sensor network node data processing and transmission. Then build Zig Bee star network, complete the wireless transmission of data and the use of simulation software NS2 network simulation. Patients can handle through the center of the platform, issue commands to the network terminal acquisition, communication base station via the PC, the collected data will be displayed in the heart by using VB6.0 MSComm control in development and design of the user interface. Because there are some outside noise interference to the heart sound signal acquisition, preprocessing needs to be simple and characteristic analysis process. Pretreatment process consists of the collected signals framing, endpoint detection and de-noising three parts. Framing is the use of a sliding rectangular window processes the samples, endpoint detection using dual-threshold measurement method, denoising using the wavelet algorithm. Finally, Mel Frequency Cepstral Coefficients of acquired heart sound signal characteristic analysis, to express a good heart sound signal characteristics in the low frequency band. In this paper, to achieve a wireless acquisition of heart sound signals, and completed the acquisition signal preprocessing and feature analysis, to achieve the desired objective of the experiment.