The minimum number of state variables required is the order of the system. 所需要的狀態變數的最低數量是系統的階次。
The order tracking technique is combined with cepstrum analysis and then the order cepstrum analysis technique is presented. 將常規的倒譜分析技術與階次分析相結合,提出了階次倒譜的齒輪箱故障診斷方法。