Analysis of the Periodically Non-stationary Structure for Modulated Vibration Signal

The vibration time series are analyzed using methods for periodically non-stationary random processes (PNRP). Band-pass filtering and Hilbert transform are used to extract quadrature components. The cross-covariance structure of quadratures is considered. It was shown that cross-covariances of different order quadratures result in periodical non-stationarity of the vibration signal.