Mitov I P
Centre of Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 105, 1113 Sofia, Bulgaria.
Med Eng Phys. 2004 Dec;26(10):879-87. doi: 10.1016/j.medengphy.2004.08.014.
A method for reduction of power line interference (PLI) in electrocardiograms with sampling rate integer multiple of the nominal power line frequency is developed and tested using simulated signals and records from the databases of the American Heart Association and the Massachusetts Institute of Technology. The method involves parabolic detrending of the ECG, estimation of the signal components with frequencies corresponding to PLI by discrete Fourier transform, and minimum-squared-error approximation of decimated series of averaged instantaneous values of PLI using appropriately defined weights. Tests of the proposed method with simulated data show that for signal-to-noise ratios SNR greater than 25 dB, the logarithmic relative error is below -32 dB and the error-to-signal ratio is less than -24 dB. For lower SNR, the errors increased, and a noise attenuation of 0.6 dB is observed. The main advantage of the developed method in comparison with other simpler and faster approaches is the accurate interference reduction in cases when the power line frequency deviates from the nominal 50 or 60 Hz. Due to computational burden, the method is more suitable for off-line application, but real-time implementation, using modern processors, is also possible.
开发了一种用于减少心电图中电力线干扰（PLI）的方法，该方法使用标称电力线频率的整数倍采样率，并用美国心脏协会和麻省理工学院数据库中的模拟信号和记录进行了测试。该方法包括对心电图进行抛物线去趋势处理，通过离散傅里叶变换估计与PLI对应的频率的信号分量，以及使用适当定义的权重对PLI的平均瞬时值的抽取序列进行最小二乘误差逼近。用模拟数据对所提出方法的测试表明，对于信噪比SNR大于25 dB的情况，对数相对误差低于 -32 dB，误差与信号比小于 -24 dB。对于较低的SNR，误差会增加，并且观察到噪声衰减为0.6 dB。与其他更简单、更快的方法相比，所开发方法的主要优点是在电力线频率偏离标称50或60 Hz的情况下能够准确减少干扰。由于计算负担，该方法更适合离线应用，但使用现代处理器也可以进行实时实现。
