To further enhance the early diagnose precision and efficiency for rotor crack under condition of strongly noise, AE signals is applied to extract fault feature of early rotor cracks with the advantages of strong anti-noise ability, clear fault feature. Based on the Pseudo Wigner-Ville Distribution (PWVD), the amplitude and frequency as feature vector are extracted from the AE signal in this pa...

The objective of this study is to establish the effectiveness of four different time-frequency representations (TFRs)--the reassigned spectrogram, the reassigned scalogram, the smoothed Wigner-Ville distribution, and the Hilbert spectrum--by comparing their ability to resolve the dispersion relationships for Lamb waves generated and detected with optical techniques. This paper illustrates the u...

New method of observation and diagnosis of inverter-fed induction motor drives is developed and tested. Unsymmetrical conditions concerning the machine impedances or valves operation are reflected in the spectrum of the current space-phasor. The spectrum of the space-phasor was estimated with the help of the Wigner-Ville distribution (WVD) and its time-frequency representation with excellent ti...

A time-frequency distribution provides many advantages in the analysis of multicomponent nonstationary signals. The simultaneous signal representation with respect to the time and frequency axis defines the signal amplitude, frequency, bandwidth, and the number of components at each time moment. The Rényi entropy, applied to a time-frequency distribution, is shown to be a valuable indicator of ...

The Wigner higher order moment spectra (WHOS) are defined as extensions of the Wigner-Ville distribution (WD) to higher order moment spectra domains. A general class of time-frequency higher order moment spectra is also defined in terms of arbitrary higher order moments of the signal as generalizations of the Cohen’s general class of time-frequency representations. The properties of the general...

The on-axis intensity distribution, or the Strehl ratio versus defocus, is described in a phase-space domain in terms of the Wigner distribution function. A coordinate transformation that is defined for a general annular aperture is employed to convert the pupil amplitude transmittance into a one-dimensional function. We show that the single display of the Wigner distribution function associate...