User manual

Code: ENIGMA III User Manual
Edition: 1 Revision: 4
Date: 19/12/2008
Page: 28/97
2.7 FFT processing.
The above described DFT (Discrete Fourier Transform)
processing needs a lot of CPU resources. In case the DFT
processing can't manage the acquired data, some optimizations
can be used. DFT works on the number of samples being a
power of 2 faster than on an arbitrary number of samples. This
optimization is called FFT (Fast Fourier Transform)
The data is split into two overlapping groups, both groups
have a 'power of 2' number of samples. Previously described
DFT (now FFT) performed on both groups and then results are
averaged.
If the number of samples is exactly a power of 2, then no
splitting is needed.
Parameter: AcfMode
GAMIC Proprietary
Illustration 20: FFT processing