Wavelet transform is a time-frequency signal analysis method,
which is widely used and well established. It has the local
characteristic of time domain as well as frequency domain. In
the processing of non-stationary signals, it presents better performance
than the traditional Fourier analysis. Hence, wavelet
transform has got potential application in gear box fault diagnosis
in which features are extracted from the wavelet transform
coefficients of the vibration signals. Continuous wavelet transform
(CWT) could put the fine partition ability of wavelet transform
to good use, and is quite suitable for the gear box fault
diagnosis. In this work, the coefficients of Morlet wavelet were
used for feature extraction. A group of statistical features like
kurtosis, standard deviation, maximum value, etc., form a set
of features, which are widely used in fault diagnostics, are extracted
from the wavelet coefficients of the time domain signals.
Selection of good features is an important phase in pattern recognition
and requires detailed domain knowledge. The decision
tree using J48 algorithm was used for identifying the best features
from a given set of samples. The selected features were
fed as input to SVM for classification.