提出了往复机械特征频段加速度信号的调幅调频模型 ,并基于此模型用标准解调法Hilbert变换法推导出了特征频段加速度信号的解调分解公式。分析和解调测试说明 ,提出的解调分解方法可成功地实现对特征频段加速度信号的解调分解。在往复机械诊断中的运用实例说明 ,特征频段信号经解调分解获得的新参量对往复机械的故障诊断是有意义的 Based on this model, the demodulation and decomposition formulas of the acceleration signal in the characteristic frequency band are deduced by the Hilbert transform method of the standard demodulation method. Analysis and demodulation test shows that the proposed demodulation and decomposition method can successfully demodulate and decompose the acceleration signal of the characteristic band. The practical example of reciprocating machine diagnosis shows that the new parameters obtained by the demodulation and decomposition of the characteristic frequency band signal are meaningful to the fault diagnosis of the reciprocating machine