动态心电信号中消除极化电压的数字滤波方法

A Digital Filtering Method for Eliminating DC Offset in Ambulatory ECG Signals

在动态心电信号采集中,极化电压很容易使放大器饱和。传统的方法是采用高通滤波模拟电路来消除,但是输出往往会有残留。如果提升高通滤波截止频率,则会导致心电信号低频段失真。该文采用Savitzky-Golay(SG)平滑滤波器,结合单边点数M和多项式的阶次p拟合了动态心电信号中的极化电压成分,用原始信号减去拟合信号从而得到无极化电压的心电信号。实验表明,用SG平滑滤波器消除极化电压是可行的,滤波后的心电信号有效成分没有任何丢失。

The amplifier is easy to saturation because of polarization voltage in ambulatory ECG acquisition. The traditional way is using analog high-pass filter to eliminate, but the output tends to have a residue. If upgrading high-pass filter cutoff frequency, it will lead to low frequency distortion of ECG signals. In this paper, a Savitzky-Golay (SG) smoothing filter has been designed by combining the single edge point M and the polynomial order p, which can fit the polarization voltage components of ECG signals, filter useful components and get drift-free ECG signals by using the subtraction algorithm. The results of ECG filtering experiment verify the feasibility of the SG smoothing filter, and show the filtered ECG signal without any losses of useful components.