Bearing Monitoring using Cepstrum Analysis
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This example shows the application of computing the cepstrum of a signal to monitor the condition of a bearing.
Cepstrum analysis has many applications, such as echo cancellation and speech analysis. One of the most important applications is machine diagnosis, where you use cepstrum analysis to separate the convoluted signals and detect periodicities in the spectrum.
If you attach a sensor directly to the bearing that contains defects, you can see peaks obviously in the signal acquired by the sensor. However, you can attach sensors only to the cast shell of a machine. The cast shell that acts as a filter blurs the acquired signal. Therefore, the acquired signal is in fact a convoluted signal by the impulse response of the cast shell. You might not be able to see obvious peaks in the signal acquired from the cast shell. By computing the cepstrum, you can deconvolute the signal that the bearing generates from the impulse response of the cast shell.
This example simulates the impulse response of the cast shell with a lowpass filter and uses the TSA Real Cepstrum VI to compute the cepstrum of the signal. This program is a shipping example VI included with the Advanced Signal Processing Toolkit for NI LabVIEW.
This software is written in LabVIEW, a graphical programming language designed for scientists and engineers. For more information about LabVIEW, visit ni.com/labview.
Advanced Signal Processing Toolkit Example Programs
The National Instruments Advanced Signal Processing Toolkit is a suite of high level VIs, libraries, software tools, example programs, and utilities for time-frequency analysis and digital filter design. With this toolkit, you can experiment and develop with modern analysis techniques that include wavelets, super resolution (model-based) spectral analysis, and joint time-frequency analysis (JTFA). Also included is the National Instruments LabVIEW Digital Filter Design Toolkit., which allows you to interactively design and characterize finite impulse response (FIR) and infinite impulse response (IIR) filters.
More information on National Instruments signal processing can be found at the Signal Processing Resource Center.
Front Panel
This is a picture of the VI's front panel. To view the block diagram and additional documentation, download the attached file.
This example requires LabVIEW and the Advanced Signal Processing Toolkit.
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TSA
No time series analysi in Adv. Sig.
Processing toolkit!!!! So cannot run VI
- Steve Kavanagh, Lloyd's Register EMEA. steve.kavanagh@lr.org - Jan 24, 2008
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