Request assistance with obtaining frequency with the highest amplitude in a signal

[thermactor]

Hello,

I am a new LabView user, and am attempting to use LabView for my graduate project.

I need to take an audio signal, and extract, as a numerical value, the predominant frequency of the sample.  That is, the frequency in the sample that has the highest amplitude.  The audio signals are pretty pure, as they're generated by a sine generator and speaker, and picke dup by a microphone.

So far, I've found the Contiunous Sound Input VI from the LabView Examples.  I modified it, and added the Auto Power Spectrum VI and the Power & Frequency Estimate VI.  This Power and Frequency Estimate VI is apparently supposed to output the estimated frequency peak and power peak.

However, when I attach an indicator to it, and run it, I get power peaks, but just zeros for the frequency peak indicator.

I was wondering if perhaps I am misunderstanding the use of this VI, or just doing a littel something wrong.  Is there a better method for doing what I'm trying to do?

Thanks much,

Wes W.

318-458-7042

hurst84@gmail.com

[Dennis_Knutson]

I think you have the general idea correct but you may have wired one or more of the functions incorrectly. Have you looked at the shipping example called Sound Card Simple Spectrum Analyzer? It uses Auto Power Spectrum and Power & Frequency Estimate. Make sure that the dt input of Auto Power Spectrum is correct and that the df output is wired to the df input of Power & Frequency Estimate. You can also post your VI to have someone look at it.

[thermactor]

Dennis,  Thanks very much for the reply.  I have looked through the example finder, and am unable to find the example that you mention.  Do you know of a source for this example VI?

I have wired a control to dt, and have connected df output to the df input on the P&F Estimate VI.

I'm going to attempt to attach the VI to this message.

Thanks again,

Wes

[Dennis_Knutson]

I don't have 8.0 so I can't open your VI. the example I mentioned was in 7.1 and earlier versions so I'm not sure why it would not be included. I've attached it here.