Ferdjallah M, Barr R E
Biomedical Engineering Program, University of Texas, Austin 78712.
Comput Biomed Res. 1990 Oct;23(5):473-89. doi: 10.1016/0010-4809(90)90035-b.
This paper presents two new local processing frequency-domain methods for the removal of powerline noise from electrophysiological signals. The first is based on an iterative division or a multiplication of a set of frequencies centered at 60 Hz. The second users a basic property of the natural logarithm to smooth the 60-Hz noise. Both methods are intended to reduce powerline noise without affecting the frequency spectrum of the signal in the regions surrounding 60 Hz. For illustration, these local processing methods are applied to artificial and real electrocardiographic (ECG) data and are compared to a fixed IIR notch digital filter which is designed by pole-zero placements on the unit circle. The performance of each method is measured by the error squared, which is the square of the difference between the original noise-free signal and the filtered noisy ECG. Finally, since the two methods are iterative processes, comparison of their rate of convergence to a predefined noise reduction level is considered.
本文提出了两种新的局部处理频域方法，用于去除电生理信号中的电力线噪声。第一种方法基于以60Hz为中心的一组频率的迭代除法或乘法。第二种方法利用自然对数的基本特性来平滑60Hz噪声。两种方法都旨在降低电力线噪声，同时不影响60Hz周围区域信号的频谱。为了说明，这些局部处理方法应用于人工和真实的心电图（ECG）数据，并与通过在单位圆上进行零极点配置设计的固定IIR陷波数字滤波器进行比较。每种方法的性能通过误差平方来衡量，误差平方是原始无噪声信号与滤波后的有噪声ECG之间差值的平方。最后，由于这两种方法都是迭代过程，因此考虑比较它们收敛到预定义降噪水平的速率。
