National Instruments Toolkit manual

NI Spectral Measurements Toolkit

This document explains how to use the NI Spectral Measurements Toolkit

(SMT) in LabVIEW and LabWindows™/CVI™ for frequency-domain

measurements.

Conventions............................................................................................2

Using the Spectral Measurements Toolkit..............................................3

Integrating the Spectral Measurements Toolkit...............................4

Locating the Spectral Measurements Toolkit..................................4

SMT Programming Flow Diagram.........................................................5

Advanced-Level VIs........................................................................6

Using LabVIEW Spectral Measurements Examples.............................. 7

SMT Simulation Examples..............................................................7

SMT Spectrum Analyzer (simulated).......................................7

SMT ACP (simulated)..............................................................8

Using LabWindows/CVI Spectral Measurements Examples................. 9

Continuous Zoom FFT.....................................................................9

Frequency Response Measurement .................................................9

Cross Power Spectrum Measurement..............................................10

Using Spectral Measurements Toolkit Techniques................................ 10

Zoom FFT........................................................................................10

Continuous Zoom FFT.....................................................................12

Block Zoom FFT............................................................................. 14

Determining When to Use Continuous or Block Zoom FFT...........14

Zoom Spectrogram.......................................................................... 15

Configuring Zoom FFT VIs....................................................................18

Center Frequency and Span.............................................................18

Resolution Bandwidth, Spectral Lines, and Window...................... 20

Choosing Useful Configuration Parameters.................................... 22

Spectral Domain Averaging....................................................................24

Averaging Conventions...................................................................25

Averaging Options...........................................................................26

Averaged FFT Spectrum..................................................................27

Averaged Power Spectrum.............................................................. 28