电子听诊器信号采集【毕业论文】.docVIP

- PAGE I - 本科毕业设计 （20 届） 电子听诊器信号采集 所在学院 专业班级 电气工程及其自动化 学生姓名 学号 指导教师 职称 完成日期 年 月 PAGE I 摘　要 【摘要】 心脏病是威胁人类生命健康的疾病之一，听诊器是对其检测的一种有效工具，但是传统听诊器存在许多不足之处，影响了疾病诊断的准确性[3]。 本课题的研究目的是为电子听诊器处理器提供采集并处理过的心音信号，以便处理器对信号进行其他处理。信号采集涉及到心音转为电信号，对电信号进行放大滤波处理，以及自动增益。心音转为电信号采用传统听诊器连接驻极体话筒来实现，传统听诊器将震动通过管道传播，震动较为强烈，然后通过驻极体话筒将震动信号转为电信号，完成信号采集。由于信号较小，采用放大电路进行一定程度的放大，以便后续处理，然后将信号进行低通滤波，只留下小于1KHz的信号。关键在于对信号进行自动增益，使输出信号峰峰值小于1V，采用N沟道场效应管的电阻可变性，控制电压采用信号经过二极管检波然后滤波得到纹波较小的直流电压，因为纹波的不可消除性，输出信号会不可避免的有一定的失真，可以通过增大电容来减小失真。 【关键词】放大；滤波；自动增益。 Abstract 【ABSTRACT】 Heart disease is the disease threatens human health,the stethoscope is one of effective tool to test heart disease , but deficiency of traditional stethoscope mpact the disease diagnosis accuracy. This purpose of topic is to provide signal of electronic stethoscope and treated for heart sound signals to other treatment signal processor. Signal acquisition involves heart sounds into electrical signals, amplification filtering processing of electrical signals, and the automatic gain. Heart sounds of electrical signals connect with traditional stethoscope to realize a diode microphone, the traditional stethoscope will shake, shake spread through a pipe, and then through relatively intense in extremely body microphones will be converted to electrical signals, vibration signals complete signal acquisition. Due to the smaller by amplifying circuit, signal to a certain degree of up, so that the follow-up treatment, then will signal low pass filtering, leaving only less than 100Hz signal. The key lies is automatic gain, to make the output signal V-V value is less than by N 1V gully, the resistance of the mosfet using signal, the control voltage variability after diode detection then filter get ripple smaller dc voltage, because ripple can not be eliminate, output signal will inevitably have distortion, we can reduce distortion by increasi