蓝牙心电采集终端的设计与实现

Design and Implementation of Bluetooth ECG Acquisition Terminal

现阶段医护用心电(ECG)监护设备价格昂贵,移动性差。为此,设计了一套基于ADS1298的蓝牙心电采集终端。采集终端主要由微控制单元(MCU)、采集前端、蓝牙模块以及不同压值电源等部分组成。终端选取TM4C123GH6PM系列单片机作为控制芯片。该控制芯片具有高效的信号处理及浮点运算功能,同时集成了高级运动控制的脉冲宽度调制(PWM)和正交编码器接口(QEI)及精密模拟信号处理功能,并且延续了Cortex-M处理器的低功耗、低成本和易使用的优点。使用TI芯片ADS1298采集人体心电信号。芯片内置右腿驱动放大器、威尔逊中心终端(WCT)以及PACE检测电路等,可持续进行导联脱落的检测。数据经过处理后,存储于SD卡,并在LCD液晶屏实时显示心电波形。选用蓝牙芯片与外界设备交互,通过蓝牙端口对接传输心电图数据。电路板采用电源隔离及滤波芯片以消除工频干扰,结合无限脉冲响应(IIR)、有限脉冲响应(FIR)数字滤波技术实现信号杂波消除。该心电采集终端具有体积小、功耗低的特点,用户操作简单、使用方便。

At present,the healthcare electrocardiogram（ ECG） monitoring equipment is expensive and has poor mobility. Thus,a Bluetooth ECG acquisition terminal based on ADS1298 has been designed. The acquisition terminal is mainly composed of microcontrol unit（ MCU）,acquisition front-end,Bluetooth module,and power supplies of different voltages. TM4 C123 GH6 PM series single-chip microcomputer is selected as the control chip. This chip has efficient signal processing and floating point arithmetic capabilities,integrates the advanced motion control of pulse width modulation（ PWM） and quadrature encoder interface（ QEI） functions as well as the precision analog signal processing functions,and continues the advantages of low power consumption and low cost of the Cortex-M processor. Using TI chip ADS1298 to collect human ECG signal,its built-in right leg driver amplifier,Wilson Center Terminal（ WCT） and PACE detection circuit,etc.,can continuously conduct lead-off detection.After data processing,the data are stored in SD card,and the ECG waveforms can be displayed on LCD screen in real time. The Bluetooth chip is selected to interact with the external devices and transmit the ECG data through the Bluetooth port. Power isolation and filter chip are adopted in circuit boards,to eliminate power frequency interference,and the signal clutters are eliminated by combining infinite impulse response（ IIR） and finite impulse response（ FIR） digital filtering technologies. The ECG acquisition terminal features small size,low power consumption and ease operating.