Extracting frequency information from sound array

[wond3rboy]

Hi, i am experimenting with acquiring sound in labview 8.6 using a microphone. I am taking 100000 samples at a frequency of 22050 Hz.  What i cant understand is how to get the frequency information after the FFT function so that i can filter the noise out and also do correlation(which is the second phase of this VI). I am attaching my VI.

Thanks.

[Remi.D]

Hello, 

In your VI, you use a waveform, you have information "dt" which is the inverse of the sampling frequency. Moreover, adding the size of a table function, you can know the array size "Extracted Sound Array.

To rebuild the frequency table, you can use a for loop with "N" iterations = array size "Extracted Sound Array".
In this loop, you create a table using a shift register that contains information (1/dt). This table will contain elements of frequency, which must then be reversed. I am attaching an Exemple

Best regards,

[DFGray]

Do you have the tone extraction VIs?  Specifically, Extract Multiple Tone Information may be what you want.  Unless, of course, this is a homework assignment.  In which case, you should take a look at the online version of Numerical Recipes in C and learn how FFTs and power spectra are generated.