Low level routine
fr -
eng
convolr_c - finite impulse response filter by fft and overlap-add method computational routine
- n :
size of the original vector
- nb_coef :
length of the impulse response vector
- m1 :
size of the fft vector (2^x)
- [z1_r;z1_i] :
address of the input complex vector 1 (signal)
- [z2_r;z2_i] :
address of the input complex vector 2 (impulse reponse)
- [y_r;y_i] :
address of the output complex vector
- z_r :
address of the overlaped word
/* convolr_c subroutine
* FIR computation
* with FFT convolution
* and overlap-ad method
*
* Copyright (C) 2007-2011 Alan Layec
*
* This file is part of modnumlib.
*
* modnumlib is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* modnumlib is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with modnumlib; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
/* REVISION HISTORY :
* $Log$
*/
#include "modnum_lib.h"
/* convolr_c routine qui realise un filtre FIR
* par multiplication dans le domaine frequentiel
* avec mise mémoire .
*
* n : taille du mot original
* nb_coef : longueur de la réponse impulsionnelle
* m1 : taille de la fft
* [z1_r;z1_i] : adresses de départ du vecteur complexe 1
* [z2_r;z2_i] : adresses de départ du vecteur complexe 2
* [y_r;y_i] : adresses de départ du vecteur complexe résultat
* z_r : adresse de départ du mot mémoire
*
* utilise : convolfft_c
* overlapadr_c
*/
void convolr_c(int *n,int *nb_coef,int *m1, \
double *z1_r,double *z1_i, \
double *z2_r,double *z2_i, \
double *y_r,double *y_i,double *z_r, \
fft_pr_struct *fft_pr)
{
/*déclaration*/
int i;
/*ajoute les zéros au vecteur z1_r*/
for(i=0;i<((*m1)-(*n));i++) {
z1_r[(*n)+i]=0.;
}
/*place valeur img z1_i a zero*/
for(i=0;i<(*m1);i++) {
z1_i[i]=0.;
}
/*ajoute les zéros au vecteur z2_r*/
for(i=0;i<((*m1)-(*nb_coef));i++) {
z2_r[(*nb_coef)+i]=0.;
}
/*place valeur img z2_i a zero*/
for(i=0;i<(*m1);i++) {
z2_i[i]=0.;
}
/*Appel convolfft_c*/
convolfft_c(m1,&z1_r[0],&z1_i[0],&z2_r[0],&z2_i[0],&y_r[0],&y_i[0],fft_pr);
/*Appel overlapad_c*/
overlapadr_c(m1,n,nb_coef,&y_r[0],&z_r[0]);
}
A. Layec