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目录
1.引言..........................................................................1
1.1 心电图仪的研究现状........................................................2
1.2 心电图仪的发展趋势........................................................3
1.3 研究心电图仪的意义........................................................4
2.简易心电图仪的原理............................................................5
2.1 心电图仪的工作原理........................................................5
2.2 心电信号的产生机理........................................................6
2.3 心电信号的特征............................................................6
2.3.1 时域特征..............................................................6
2.3.2 频谱特征..............................................................7
3.基于 AVR 心电图仪的硬件设计....................................................7
3.1 心电图仪的硬件设计方案....................................................7
3.2 ATmega128 单片机的介绍....................................................8
3.2.1 微处理器的选型........................................................8
3.2.2 微处理器的特点........................................................9
3.2.3 ATmega128 的主要引脚功能..............................................10
3.3 信号采集电路设计..........................................................11
3.3.1 导联通道的选择........................................................11
3.3.2 差分运放的选择........................................................12
3.3.3 前置放大电路..........................................................12
3.3.4 后级放大电路..........................................................13
3.3.5 滤波电路..............................................................14
3.3.6 陷波处理电路..........................................................15
3.3.7 电平抬升电路..........................................................16
3.3.8 电源电路..............................................................17
3.4 信号处理电路设计..........................................................17
3.4.1 处理电路方案..........................................................17
3.4.2 存储电路..............................................................18
3.4.3 按键电路..............................................................18
3.4.4 LCD 显示电路...........................................................19
4.基于 AVR 心电图仪的软件设计....................................................19
4.1 主程序流程................................................................19
4.2 串口初始化................................................................20
4.3 信号采集程序设计..........................................................20
4.4 液晶显示程序..............................................................21
4.5 按键程序..................................................................22
5 结束语........................................................................23
参考文献........................................................................24