当检测电信号的瞬时大小时,必须弄清其参考电平以测出相对它的信号值大小。在心电技术中,这个参考电平通常从ECG的等电位期中得出,然而这个周期不易从ECG中准确地确定,并且这个方法的应用可能还有疑问。由此得到的信号电平通常不足够清楚,至于在心率快时,这个周期太短以致于不能利用或者这个周期根本不 When detecting the instantaneous size of an electrical signal, its reference level must be ascertained to determine the magnitude of the signal relative to it. In electrocardiography, this reference level is usually derived from the equipotential period of the ECG, however, this period is not easily determined accurately from the ECG and the application of this method may be in doubt. The resulting signal level is usually not sufficiently clear, as in the fast heart rate, this period is too short to be utilized or the period is not at all