libdspl2.0
Digital Signal Processing Algorithm Library

Fast Fourier Transform Object Data Structure. More...
#include <dspl.h>
Data Fields  
complex_t *  w 
complex_t *  t0 
complex_t *  t1 
complex_t  w32 [32] 
complex_t  w64 [64] 
complex_t  w128 [128] 
complex_t  w256 [256] 
complex_t  w512 [512] 
complex_t *  w1024 
complex_t *  w2048 
complex_t *  w4096 
int  n 
Detailed Description
Fast Fourier Transform Object Data Structure.
The structure stores pointers to twiddle factors and arrays of intermediate data of the fast Fourier transform algorithm.
The libdspl2.0 library uses an FFT algorithm for composite size.
 Parameters

n The size of the FFT vector for which memory is allocated in the structure arrays.
The parametern
must be equal to an integer power of two (radix 2).
w Pointer to the vector of twiddle factors.
The size of the vector is[n x 1]
.
The memory must be allocated and an array of twiddle factors must be filled with the fft_create function.
t0 Pointer to the vector of intermediate results of the FFT algorithm.
The size of the vector is[n x 1]
.
Memory must be allocated by fft_create function.
t1 Pointer to the vector of intermediate results.
The size of the vector is[n x 1]
.
The memory must be allocated with the fft_create function.
w32 Static twiddle factors vector for 32points FFT.
w64 Static twiddle factors vector for 32points FFT.
w128 Static twiddle factors vector for 32points FFT.
w256 Static twiddle factors vector for 32points FFT.
w512 Static twiddle factors vector for 32points FFT.
w1024 Dynamic twiddle factors vector for 32points FFT.
w2048 Dynamic twiddle factors vector for 32points FFT.
w4096 Dynamic twiddle factors vector for 32points FFT.
The structure is calculated with the fft_create function once before using the FFT algorithm.
A pointer to an object of this structure may be reused when calling FFT functions.
Before exiting the program, dedicated memory for twiddle factors and arrays of intermediate data must be cleared by the fft_free function.
For example:
 Note
 It is important to note that if the object
fft_t
was created for the FFT size equal ton
, it can only be used for FFT of sizen
.
It’s also worth noting that the FFT functions independently control the size, and independently allocate the memory of the FFT object, if necessary. So if you call any function using thefft_t
structure with filled data for the FFT lengthk
for calculating the FFT of lengthn
, then the structure arrays will be automatically recreated for the lengthn
.
Field Documentation
◆ n
int fft_t::n 
Definition at line 292 of file dspl.h.
Referenced by fft_create().
◆ t0
complex_t* fft_t::t0 
Definition at line 280 of file dspl.h.
Referenced by fft_create(), fft_free(), and ifft_cmplx().
◆ t1
complex_t* fft_t::t1 
Definition at line 281 of file dspl.h.
Referenced by fft(), fft_cmplx(), fft_create(), fft_free(), and ifft_cmplx().
◆ w
complex_t* fft_t::w 
Definition at line 279 of file dspl.h.
Referenced by fft_create(), and fft_free().
◆ w1024
complex_t* fft_t::w1024 
Definition at line 289 of file dspl.h.
Referenced by fft_create(), and fft_free().
◆ w128
complex_t fft_t::w128[128] 
Definition at line 286 of file dspl.h.
Referenced by fft_create().
◆ w2048
complex_t* fft_t::w2048 
Definition at line 290 of file dspl.h.
Referenced by fft_create(), and fft_free().
◆ w256
complex_t fft_t::w256[256] 
Definition at line 287 of file dspl.h.
Referenced by fft_create().
◆ w32
complex_t fft_t::w32[32] 
Definition at line 284 of file dspl.h.
Referenced by fft_create().
◆ w4096
complex_t* fft_t::w4096 
Definition at line 291 of file dspl.h.
Referenced by fft_create(), and fft_free().
◆ w512
complex_t fft_t::w512[512] 
Definition at line 288 of file dspl.h.
Referenced by fft_create().
◆ w64
complex_t fft_t::w64[64] 
Definition at line 285 of file dspl.h.
Referenced by fft_create().
Generated on Mon Dec 14 2020 14:02:36 for libdspl2.0 by 1.8.20