Scripts/FFTutils
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FFT Utils provides windowing and other utility functions useful when using the FFT addon.
Download the script: File:Fftutils.ijs
Windows
NB.*hanning v hanning function of proper length NB.*hamming v hamming function of proper length NB.*blackmanharris v blackman-harris with minimum 4-term (monad) or arbitrary (dyad) values NB.*nuttall v blackman-harris with Nuttall parameters
Utility Functions
NB.*twl v twenty log NB.*tel v ten log
Example
This command plots twenty times the log magnitude of the FFT of a time series called data with each of the windows applied. The maximum is scaled to 0, and the minimum is clamped at -100.
'keystyle open; key Unwindowed Nuttall "B-H 4" Hamming Hanning' plot (_100 >.])(- >./)"1 twl | fftw"1 (], (* nuttall), (* blackmanharris),(* hamming),: (* hanning)) data
This example shows the effect of windowing on a simple sine wave.
'keystyle open; key Unwindowed Nuttall "B-H 4" Hamming Hanning' plot(- >./)"1 twl | fftw"1 (], (* nuttall), (* blackmanharris),(* hamming),: (* hanning)) sin i. 128
See Also
Contributed by Bill Harris