National Instruments NI Spectral Measurements Toolkit - Manual

USER GUIDE
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.
Contents
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