便携式心电信号采集电路设计

Portable ECG acquisition circuit

针对便携式心电采集电路体积小、性能高的要求,以AD620和TL064为核心设计出由前置放大电路、无源高通滤波、二阶低通滤波、陷波器和二级放大电路等组成的采集电路。前置放大电路的设计和参数的选择抑制了噪声,省去了通常采集电路中右腿驱动的部分;通过对二阶滤波和陷波器的参数选择和调试,得到较理想的滤波效果。A/D转换是利用FPGA设计控制模块来实现的,其他存储、显示模块可以集中在FPGA上,增加了便携设备的集中度。实验和仿真结果表明,在简单电路和参数下能够得到对50 Hz频率衰减几乎为0,在1 000 Hz时衰减-40 dB,幅度放大1 000倍的心电信号。

To design a small-size and high-performance ECG acquisition circuit, this design employes AD620 and TL064 as its core, comprised other components such as preamplifier circuit, passive high-pass filter, second-order low-pass filter, trap filter and second amplifier. The design of the preamplifier and the selection of parameters both reduced the noise, omitted the usual right-leg drive part; after selecting and debugging the parameters of the second-order filter and the band filter, it got desired filtering effects. The analog-digital converter was based on the control module of FPGA, and other components such as memory and diplay modules were also integrated in FPGA, it increased the degree of concentration of portable devices. Results of experiments and simulations show that under the simple circuit and parameters, it made the ECG signal the attenuation of almost zero in 50Hz, -40dB in 1000Hz, and an amplitude amplification by 1000 times.