Chang K S, Snellen J W
Eur J Appl Physiol Occup Physiol. 1982;49(1):97-109. doi: 10.1007/BF00428968.
The methodology of using frequency analysis in order to identify types of system(s) is discussed. A number of models with their characteristic Nyquist plots are presented graphically, to facilitate the identification of various types of systems by pattern recognition. A small series of measurements of oxygen consumption and heart rate has been carried out to illustrate the possibilities and limitations of the use of frequency analysis in exercise physiology. With a step function method one can only establish whether a system has multiple components in parallel or not, but with the frequency analysis method one can identify whether a system has multiple components in parallel or in series. It was found that under moderate exercise, the response of oxygen consumption to exercise is a system with multiple components in series, but the response of heart rate to exercise is a system with multiple components in parallel. The data that were obtained are in agreement with those produced by other authors, but the curves to fit the observed data were obtained using second order linear transfer functions.
讨论了使用频率分析来识别系统类型的方法。以图形方式展示了一些具有其特征奈奎斯特图的模型，以便通过模式识别来识别各种类型的系统。进行了一小系列耗氧量和心率的测量，以说明在运动生理学中使用频率分析的可能性和局限性。使用阶跃函数方法只能确定一个系统是否具有并联的多个组件，但使用频率分析方法可以识别一个系统是否具有并联或串联的多个组件。研究发现，在适度运动下，耗氧量对运动的反应是一个具有多个串联组件的系统，但心率对运动的反应是一个具有多个并联组件的系统。获得的数据与其他作者得出的数据一致，但拟合观测数据的曲线是使用二阶线性传递函数得到的。
