“…Traditional mathematical processing methods mainly include linear stationary mathematical transformation methods and non-stationary, non-Gaussian distribution and nonlinear random signal processing methods. The linear stationary mathematical transformation methods are represented by time domain statistical analysis, 1 frequency domain statistical analysis, 2 Fourier transform analysis, 3 time series model analysis method, 4 refined spectrum analysis, 5 holographic spectrum analysis, 6 singular spectrum noise reduction method, 7 matching tracking analysis, 8 and geometric fractal analysis method. 9 Non-stationary, non-Gaussian distribution, and nonlinear random signal processing methods are represented by high-order spectral analysis, 10 principal component analysis, 11 short-time Fourier transform (STFT), 12 Wigner–Ville distributing, 13 wavelet transform (WT), 14 cyclic stationary analysis method, 15 random resonance method, 16 empirical mode decomposition (EMD), 17 Hilbert–Huang transform (HHT), 18 and the second-generation WT method.…”