回声在时间信号的功率谱里给出了周期性的成份,使谱图脉动增大。利用倒频谱(Cepstrum),可将回声的影响消除,得到接近无回声影响的真实功率谱,以便在频域里对噪声进行更好的分析。本文介绍了倒频谱的基本原理,分析了混有回声信号形成的机理及其所造成影响的消除方法。对一台在无消声条件下测量到的车床床头箱的噪声信号,用倒频谱进行了分析处理,给出了分析结果。 The echo gives a periodic component in the power spectrum of the time signal, increasing the pulsation of the spectrum. With Cepstrum, the effects of the echoes can be eliminated, resulting in a near-anechoic real power spectrum that allows for a better analysis of the noise in the frequency domain. This paper introduces the basic principle of cepstrum, analyzes the formation mechanism of the mixed echo and the elimination method of its influence. The noise signal of a lathe headstock measured under non-muffling conditions is analyzed by cepstrum and the analysis results are given.