Instantaneous Amplitude-Frequency Feature Extraction for Rotor Fault Based on BEMD and Hilbert Transform

Figure 15

The oil whirl signal z: (a) the 3D time-domain wave of z; (b) the 2D plane of z; (c) the Fourier spectrum of Real[z]; (d) the Fourier spectrum of Imag[z].

(a)

(b)

(c)

(d)