體表心電放大器的研究與設(shè)計


頁數(shù)：29 字數(shù)：9425

體表心電放大器的研究與設(shè)計

摘 要

本文主要介紹了心電信號的放大、濾波和光電耦合。
鑒于心電信號的幅度僅為微伏、毫伏量級；人體攜帶有工頻干擾以及所測量的參數(shù)外的其他生理作用的干擾；心電信號源本身是高內(nèi)阻的微弱信號源，通過電極提取又呈現(xiàn)出不穩(wěn)定的高內(nèi)阻性質(zhì)等因素,電路采用了具有高輸入阻抗、高共模抑制比、低噪聲、低溫漂的差動放大電路。
造成生物電信號提取過程的主要干擾,是近場50Hz干擾源，因為各種生物電信號中大都包含有50Hz的頻率成分，而且生物電信號的強度遠遠小于50Hz的干擾。近場50Hz干擾不僅直接影響心電信號的提取，而且它存在于所有的測量環(huán)境中。因此本電路采用了雙T濾波器來抑制近場50Hz干擾。
為了人體的安全，本電路采用了浮地形式互補式光電耦合電路，光電耦合器件具有重量輕,應(yīng)用電路結(jié)構(gòu)簡單,成本低等突出的優(yōu)點。在生物醫(yī)學電子學中得到廣泛應(yīng)用,它具有良好的線性和一定的轉(zhuǎn)換速度。既可以作為模擬信號的轉(zhuǎn)換,也可以作為數(shù)字信號的轉(zhuǎn)換。光電器件受到歡迎的另一個原因是它能實現(xiàn)與TTL電路的兼容?；パa形式的耦合級電路，它利用兩個光電器件特性的對稱性提高耦合級電路的線性度。以便實現(xiàn)人體與電器的隔離。
關(guān)鍵詞： 心電信號,放大,濾波器,光電耦合

RESEARCH AND DESIGN OF THE ELECTRIC AMPLIFIER OF THE HEART FROM THE SURFACE OF BODY
ABSTRACT
This text introduces the amplifying of the heart electric signal, strain waves and photoelectric coupling mainly。
Seeing that the range of heart electric signal is only in quantity grade of microvolt, millivolt。The body of human carries interfering of frequently engineer and interference on other physiological function outside the parameters measured; The hearts electric signal source itself is a faint signal source with high hinder inside, Draw it through the electrode and demonstrate unstable factors such as high hindering inside nature ,etc。There are high input impedance, high suppress mould altogether, low in noise, low temperature float differential to enlarge in this circuit。
The main interference source to draw heart electric signal course is50Hz ,Because various kinds of living beings’ electric signal include 50Hz frequency, and the intensity of living beings’ electric signal is far smaller than the interference of 50Hz。 50Hz interference influent the abstraction of heart electric signal directly 。And there are 50Hz interference in all measurement environment 。This circuit adopt pairs of T wave filter to suppress 50Hz interference。
For security of human body, this circuit adopt gro