The vibration signal from the reciprocating engine is non - stationary, time - variation , so, application of HHT is a good choice.

从往复机械上得到的振动信号往往具有 非 平稳 、 非线性 特征, 因此采用HHT方法分析是一种较佳的选择.

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When nonlinearities and time variation are present , the very basis for classical techniques is removed.

当系统存在非线性和时变特性时, 经典方法赖以存在的基础就不存在了.

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