Measurement of Impulsive Distortion, Rub and Buzz and other Disturbances

The traditional distortion measurement transforms the time signal into the frequency domain to separate fundamental, harmonic and intermodulation components. This technique considers only the mean power in the analyzed interval and neglects the phase information. A new technique for the measurement of the signal distortion in time domain is presented that exploits both amplitude and phase information. It reveals the fine structure of the distortion and its dependency on frequency, displacement or other state variables. Besides the rms-value of the distortion the peak value and the crest factor are important characteristics for detection of rub and buzz phenomena. The practical application, the interpretation and the diagnostics of defects are discussed.