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信号的解调分析是通讯领域和机械故障诊断的常用方法。本文从数字滤波器的角度出发，提出了实现信号解调的正交滤波器法，即基于 Ｆ Ｉ Ｒ 正交滤波器方法和基于正交小波函数的正交滤波器方法。正交滤波器方法将带通滤波和希尔伯特变换的过程和功能有合二为一，实现过程方便。针对 Ｆ Ｉ Ｒ 正交滤波器方法的缺点，本文根据函数逼近理论，在理论上，证明了正交小波函数可以最佳一致逼近理想滤波器。并在具体应用上，介绍了采用正交小波函数构造正交滤波器时，参数的选择和信号解调分析的具体实施方法。采用正交小波函数设计的正交滤波器方法，带宽选择方便，相位的线性度高，正交性好，而且滤波器的滤波性能更优。可根据要求很方便地实现多通带信号滤波和多通带信号的解调分析
Demodulation analysis of signals is a common method in the field of communications and mechanical fault diagnosis. In this paper, from the point of view of digital filter, the orthogonal filter method to realize signal demodulation is proposed, which is based on F I R orthogonal filter method and orthogonal filter method based on orthogonal wavelet function. The orthogonal filter method combines the process and the function of the band-pass filter and the Hilbert transform to achieve the convenience of the process. Aiming at the shortcomings of the F I R orthogonal filter method, this paper proves that the orthogonal wavelet function can best approximate the ideal filter theoretically based on the function approximation theory. And on the concrete application, this paper introduces the method of selecting the parameters and analyzing the signal demodulation when using the orthogonal wavelet function to construct the orthogonal filter. The orthogonal filter designed by orthogonal wavelet function has the advantages of convenient bandwidth selection, high phase linearity, good orthogonality, and better filter performance. Multi-pass signal filtering and demodulation of multi-passband signals can be easily implemented on request