| 0,0 → 1,28 |
|---|
| This is a draft version of my Fast Hartley Transform (FHT) routine for KolibriOS |
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| Hartley transform is a real-basis version of well-known Fourier transform: |
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| 1) basis function: cas(x) = cos(x) + sin(x); |
| 2) forward transform: H(f) = sum(k=0..N-1) [X(k)*cas(kf/(2*pi*N))] |
| 3) reverse transform: X(k) = 1/N * sum(f=0..N-1) [H(f)*cas(kf/(2*pi*N))] |
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| FHT is known to be faster than most conventional fast Fourier transform (FHT) methods. |
| It also uses half-length arrays due to no need of imaginary data storage. |
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| FHT can be easily converted to FFT (and back) with no loss of information. |
| Most of general tasks FFT used for (correlation, convolution, energy spectra, noise |
| filtration, differential math, phase detection ect.) may be done directly with FHT. |
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| ==================================================================================== |
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| Copyright (C) A. Jerdev 1999, 2003 and 2010. |
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| The code can be used, changed and redistributed in any KolibriOS application |
| with only two limitations: |
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| 1) the author's name and copyright information cannot be deleted or changed; |
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| 2) the code is not allowed to be ported to or distributed with other operation systems. |
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| 18/09/2010 |
| Artem Jerdev <kolibri@jerdev.co.uk> |