Engine Knocking Monitor Using Autoregressive-moving Average Modeling
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This example shows the application of autoregressive-moving average (ARMA) modeling in examining the condition of an engine.
Under normal conditions, the vibration signal from the engine is a stationary time series. If you build an ARMA model for the stationary time series, the modeling errors are usually small. However, if the engine is not running properly due to imbalance or cracks, the vibration signal becomes a nonstationary time series. If you build an ARMA model for this nonstationary time series, the modeling errors increase.
This example uses the TSA ARMA Modeling VI to build an ARMA model for the vibration signal of an engine and uses the TSA Deviation and Variation VI to compute the noise variances, or errors, of the modeling. 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.
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This example requires LabVIEW and is included with the Advanced Signal Processing Toolkit. You can run the LabVIEW Online Evaluation to try this example. After installing the evaluation, launch LabVIEW, and navigate to Help » Find Examples... » Toolkits and Modules.
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