Streaming data to disk, need help reading data into Power Spectrum/O​ctave vi

Question

I'm streaming data to disk in one loop, however once this finishes I'd like to read the data into power spectrum vi/Octave analysis vi in another loop. The data from the read vi is a string and power spectrum vi needs 1d waveform. Does anyone have experience with this process?

Answer 1

From your general description, I gather you are streaming to a text based file (comma or tab separated spreadsheet format) and would like to analyse this data with a power spectrum or octave analysis when you finish. Since you are streaming, I assume you have a lot of data. Do you have more than one channel?
In any case, you have two simple options (and lots of complex ones). You can either read the data back from disk and convert it to a 1D array (try the Read From Spreadsheet File.vi - will get a 2D array, take the first column or the column of your choice if you have more than one channel) or you can use the Spreadsheet String to Array primitive to create an array from your text data before you save it to disk.
If your data rate is slow enough, you can analyze as you acquire and store.
Taking your data as text is very inefficient. What you really want to do is read the data as binary, use that for your analysis, and use something like the Write to Spreadsheet File.vi to save text data to disk.
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