Pad(?)逼近,时矩匹配和CauerⅡ形速分式法是频域模型降阶的三种基本方法,它们源于经典的近似技术或数学概念,而其它众多的频域降阶方法大都由此派生而来。故可称之为频域降阶的经典方法。这些方法具有一系列优点,但都存在两个众所周知的缺陷: 1) 不能保证“稳定降阶”,即由一个稳定的高阶模型可能会导出不稳定的低阶 Pad (?) Approximation, Time Matching and Cauer â ... ¢ Form Factorization are three basic methods of frequency domain model reduction. They originate from the classical approximation technique or mathematical concept, and many other methods of frequency domain reduction mostly consist of This is derived. It can be called the classical method of frequency domain reduction. These methods have a number of advantages, but both have two well-known drawbacks: 1) “Stable Order Reduction” can not be guaranteed, that is, a stable high order model may derive unstable low order