icListen AF User Guide
© December, 2017
14
5.2.4
FFT Processing Options
Not all applications require data to be processed in the same way. For this reason
icListen
has been
designed to allow multiple options for power spectrum data processing.
5.2.4.1
Overlap
It is often useful to have some overlap in the waveform data used to compute frequency data. This helps
to improve the time resolution of the resulting data, and assists in ensuring we do not miss data that
may otherwise be filtered out by the Hann windowing operation. The figures below show an example
waveform data set, divided into sections which are used to compute frequency data. These figures show
the data used with no overlap (0%) and 50% overlap.
icListen AF
uses a 50% overlap for all spectrum
data.
Figure 5-1:
FFT’s with 0% Overlap
Figure 5-2:
FFT’s with 50%
Overlap
