check for single frequency in audio spectrum

[glyman]

I am trying to input an audio signal (song) through an analog input, then check to see if a specific frequency is present, 440Hz for example, then if it is present output a boolean true.  If the specified frequency is not present, output false.  Preferable, this would be continuous with as little time delay as possible.  Any ideas?

Thanks!

[OregonGumby]

You should be able to use the Extract Single Tone  VI from the signal processing functions in the toolbox.  You would just need to compare the amplitude output from the VI to a threshold value and use the boolean output of that comparison.