Trying to find the reflection coefficient using two microphone method, why can't I output the data in units of frequency?

[Pipes]

Using LABView to collect data over an experimental setup for measuring sound absorption using the two microphone method. The program cross correlates two mic inputs and then I use a fourier transform to split the complex result into real and imaginary parts. I cant seem to output into the right units or even the right format. Any help would be great, the VI is attached. Thanks.

[The_Red_Barron]

Howdy Pipes!

The FFT PtByPt VI that you are using performs the FFT on an array of values, x, and returns an array of complex values representing FFT{X}.  This FFT function simply performs the transform math on the input array and does not take into account time/frequency in its calculation.  You can see that the blue dynamic data type wire coming from the Convolution and Coorelation Express VI is being coerced when entering the FFT PtByPt VI, thus stripping it of timing information.

I recommend that you look into using the Spectral Measurements Express VI to process the FFT of your data.

Regards,

[Pipes]

I used the Real-Imaginary Cross Spectrum to analyze data and all looks as if its running well but I seem to have trouble outputing numerical data. Is there a way to export to excel?

-Pipes

[The_Red_Barron]

If you have the Report Generation Toolkit, then you can easily use the VIs included with it to write to an Excel file.  Check out this example.

Alternately, you can use the Write To Spreadsheet File VI to create a tab delimited or comma separated spreadsheet file which can be opened by Excel.  Check out this example.

There are many more examples available in the NI Developers Community that you might find useful as well.

Regards,