In gear fault diagnosis

box vibration acceleration signal pass many transmission link and there is nonlinear cross couple of signals

the torsional vibration signals measured from transmission axle is studied to carry out fault diagnosis.The bispectrum characteristics of vibration signals obtained through two different kinds of transfer paths are compared.Frequency components of box vibration acceleration signal are complex

while torsional vibration signal transfer links are less

transfer path is direct

thus interference factors are reduced

and frequency components of the signal are simpler.Through spectrum analysis

fault feature can be clearly extracted

which is helpful for accurate fault diagnose.