National Instruments Order Analysis Toolset Extracting Orders

Chapter 3 Gabor Transform-Based Order Tracking

LabVIEW Order Analysis Toolset User Manual 3-6 ni.com

VI to perform the mask operation. Refer to the LabVIEW Order Analysis

Toolset Help for information about the Template to Mask VI.

You can consider the mask operation a time-variant bandpass filter in the

joint time-frequency domain. The center frequency of the passband equals

the frequency of the order curve. The number of elements set to TRUE

determines the bandwidth of the passband.

Extracting Orders

Figure 3-4 illustrates the order extraction and signal reconstruction

process.

Figure 3-4. Gabor Coefficients

Figure 3-4(a) shows a frequency-time spectral map after the Gabor

transform.

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024681012 15 024681012 15

024681012 15024681012 15

Time (s) Time (s)

Time (s) Time (s)

(a) Original Signal (b) Mask

(c) Masked Coefficients (d) Gabor Coefficients of the

Reconstructed Signal

Frequency (Hz)

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Frequency (Hz)

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Frequency (Hz)

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Frequency (Hz)

Contents

Main Page Important Information Warranty Copyright Trademarks Patents Contents About This Manual Chapter 1 Introduction to the LabVIEW Order Analysis Toolset Chapter 2 Order Analysis Page About This Manual How to Use This Manual Conventions Related Documentation Introduction to the LabVIEW Order Analysis Toolset Overview of the LabVIEW Order Analysis Toolset Overview of the LabVIEW Order Analysis Start-Up Kit Important Considerations for the Analysis of Rotating Machinery System Requirements Installation Example VIs Acquiring Data for Example VIs Configuring DAQ Hardware Used with Examples Acquire Data (Analog Tach) VI Acquire Data with PXI 4472 and TIO VI Page Page Order Analysis Order Analysis Definition and Application Order Analysis Basics Page Page Effect of Rotational Speed on Order Identification Constant Rotational Speed Page Variable Rotational Speed Page Page Harmonic Analysis Order Analysis Order Analysis Methods Gabor Transform Page Page Resampling Page Adaptive Filter Gabor Transform-Based Order Tracking Overview of Gabor Order Analysis Page Extracting the Order Components Page Masking Extracting Orders Reconstructing the Signal Displaying Spectral Maps Page Calculating Waveform Magnitude Resampling-Based Order Analysis LabVIEW Order Analysis Toolset Resampling Method Determining the Time Instance for Resampling Page Resampling Vibration Data Slow Roll Compensation Page Calculating Rotational Speed Digital Differentiator Method Page Averaging Pulses Page A Gabor Expansion and Gabor Transform Gabor Expansion and Gabor Transform Basics Page Page Discrete Gabor-Expansion-Based Time-Varying Filter Page Page B References C Technical Support and Professional Services Glossary Numbers/Symbols A C D Page R S W Index A C D E K M N O P