How do I Find the Frequency of an Analog Input Signal?

Updated Sep 25, 2018

Reported In

Software

  • LabVIEW

Driver

  • NI-DAQmx

Issue Details

I am unable to figure out how to display the frequency of an analog input in LabVIEW. I can chart and graph it but I am unable to find a way to display the frequency of the signal.
 

Solution

There are a couple options for finding the frequency of an analog input signal:
  • Use a counter to measure the signal's frequency as shown in this example program: NI-DAQmx: Measuring Frequency from an Analog Input. This example uses a digital counter to find the frequency of an Analog Comparison Event, which is a configured trigger output from an analog input. Note: This example does not work on all NI hardware.
  • There is an example shipped with LabVIEW showing an approach using Extract Single Tone Information VI: In Example Finder, open Analysis, Signal Processing and Mathematics » Signal Processing » Single Tone Measurements.vi.
  • Use LabVIEW's built-in signal analysis Express VIs, e.g. as shown in the example code below. DAQmx Read is wired into Tone Measurements Express VI, which calculates the signal's frequency. Similarly, Spectral Measurements Express VI is used to obtain the signal's frequency spectrum.​

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