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FFT Size

The selected FFT size directly affects the resolution of the resulting spectra.  The number of spectral lines is always 1/2 of the selected FFT size.  Thus a 1024 point FFT produces 512 output spectral lines.

The frequency resolution of each spectral line is equal to the Sampling Rate divided by the FFT size.  For instance, if the FFT size is 1024 and the Sampling Rate is 8192, the resolution of each spectral line will be:

    8192 / 1024 = 8 Hz.

Larger FFT sizes provide higher spectral resolution but take longer to compute.

Notes:
The Spectral Line Resolution and Frequency Limit values will update to automatically reflect the current Sampling Rate, FFT size, and Decimation ratio settings.
The current FFT size is always displayed in the status bar along the bottom of the application.


See also: Sampling Rate , Decimation Ratio