Cano G G, Briller S A, Coast D A
Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania 15212-9986.
J Electrocardiol. 1990;23 Suppl:176-83. doi: 10.1016/0022-0736(90)90098-m.
Observation of low amplitude components in the ECG motivated our interest in time-sequenced adaptive filtering. This technique is applicable to signals that are cyclic in nature. Two simultaneously acquired signals are used in the technique. It is assumed that the underlying signal is correlated and that noise is uncorrelated between the two channels. Instead of one enhancer that continuously adjusts its characteristics over the time course of the signal, each cycle is subdivided into intervals; a given enhancer is used only on the same corresponding interval in successive cycles. This minimizes the signal range over which the enhancer must adjust its characteristics. In the time-sequenced approach, it is important that the enhancers adapt at the same rate. Thus, each has its own feedback coefficient derived from an average of 10 consecutive ECG cycles and an estimate of noise in intervals where no signal is present. Each feedback coefficient is augmented over the first 10 beats. To improve adaptation, a means to update each filter on the preceding beat and the current beat was developed. Lastly, a weight averaging scheme was developed to circumvent weight stalling. The procedure has enabled observation of both His activity and late potentials in individual beats from signals acquired from the chest surface.
心电图中低振幅成分的观察激发了我们对时间序列自适应滤波的兴趣。该技术适用于本质上具有周期性的信号。该技术使用两个同时采集的信号。假定基础信号是相关的，并且两个通道之间的噪声是不相关的。不是使用一个在信号的时间过程中持续调整其特性的增强器，而是将每个周期细分为多个间隔；在连续周期中，给定的增强器仅用于相同的相应间隔。这使增强器必须调整其特性的信号范围最小化。在时间序列方法中，增强器以相同速率自适应很重要。因此，每个增强器都有自己的反馈系数，该系数来自10个连续心电图周期的平均值以及无信号间隔中的噪声估计值。每个反馈系数在前10个搏动中增大。为了改善自适应，开发了一种在前一个搏动和当前搏动上更新每个滤波器的方法。最后，开发了一种加权平均方案以避免权重停滞。该程序能够从胸壁表面采集的信号中观察到单个搏动中的希氏束活动和晚电位。
