Frequency Analysis VIs

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NI Sound and Vibration Measurement Suite 2009 Help

Edition Date: June 2009

Part Number: 372416C-01

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Owning Palette: Sound and Vibration VIs

Requires: Sound and Vibration Measurement Suite. This topic might not match its corresponding palette in LabVIEW depending on your operating system, licensed product(s), and target.

Use the Frequency Analysis VIs to perform averaged and non-averaged, or single block, frequency analysis. The analysis is based on the FFT.

The VIs on this palette can return general LabVIEW error codes or specific sound and vibration error codes.

Refer to the labview\examples\Sound and Vibration directory for examples of using the Frequency Analysis VIs.

Palette Object	Description
Frequency Response	Computes the frequency response and the coherence based on the stimulus and response input signals and returns the results as magnitude, phase, real, imaginary, or coherence.
Limit Test	Tests an input signal or value against user-specified limits and returns information on whether the test passed or failed and, in the case of a failure, where it failed. Limit Test accepts time-domain signals, frequency-domain signals, and scalar values as inputs. You can specify either signals or scalar values for the limits, and you can define the limits or use other signals in the project as the limits.
Peak Search	Performs a peak search in the frequency domain. You can detect either a single or multiple peaks in a magnitude spectrum or power spectrum. You can specify the magnitude threshold and frequency range to fine-tune the peak search.
Power in Band	Computes the total power in the range of interest for power, power spectral density (PSD), and magnitude spectra.
Power Spectrum	Computes the averaged magnitude spectrum, power spectrum, or power spectral density for a single or multiple channels. This step can return the spectra in root-mean-square, peak, and peak-to-peak units.
Zoom Power Spectrum	Computes the averaged zoom magnitude spectrum or zoom power spectrum. This measurement can return the spectrum in root-mean-square, peak, and peak-to-peak units. Data accumulates each time you pass new data. However, zoom analysis returns a new spectrum only when sufficient data accumulates.

Subpalette	Description
Baseband FFT VIs	Use the Baseband FFT VIs to perform baseband FFT measurements.
Spectrum Extended Measurements VIs	Use the Spectrum Extended Measurements VIs to perform advanced frequency analysis measurements.
Zoom FFT VIs	Use the Zoom FFT VIs to perform real-time zoom FFT measurements.