analyse cepstrale

CONT: When the cepstral analysis is performed ... the ball-cage vibrations and changes in vibrations that are symptomatic of wear can be detected earlier in a test than they can be by more conventional methods based on straingauge measurements. ... Cepstral analysis is particularly useful in diagnoses of gearboxes and rolling element bearings ....
OBS: A cepstrum is a spectrum of a logarithmic power spectrum. Because of this, a peak in the cepstrum indicates periodicity in the spectrum; usually, this signifies a family of harmonics at equal frequency intervals.
OBS: Cepstral analysis has been widely applied to gear monitoring. The cepstrum is well suited for the detection of sidebands in vibration spectra and for the estimation of their evolution during gear life. In addition, since the cepstrum estimates the average sideband spacing over a wide frequency range, it allows very accurate measurement of the sideband periodicity. It is therefore applicable to both detection and diagnosis of gear faults.