libdspl-2.0/dspl/src/filter_design/freqs_cmplx.c

94 wiersze
2.2 KiB
C

/*
* Copyright (c) 2015-2019 Sergey Bakhurin
* Digital Signal Processing Library [http://dsplib.org]
*
* This file is part of libdspl-2.0.
*
* is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* DSPL 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 Lesser General Public License
* along with Foobar. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "dspl.h"
#ifdef DOXYGEN_ENGLISH
#endif
#ifdef DOXYGEN_RUSSIAN
#endif
int DSPL_API freqs_cmplx(double* b, double* a, int ord,
complex_t* s, int n, complex_t *h)
{
complex_t *bc = NULL;
complex_t *ac = NULL;
complex_t num, den;
double mag;
int k;
int res;
if(!b || !a || !s || !h)
return ERROR_PTR;
if(ord<0)
return ERROR_FILTER_ORD;
if(n<1)
return ERROR_SIZE;
bc = (complex_t*) malloc((ord+1) * sizeof(complex_t));
res = re2cmplx(b, ord+1, bc);
if( res!=RES_OK )
goto exit_label;
ac = (complex_t*) malloc((ord+1) * sizeof(complex_t));
res = re2cmplx(a, ord+1, ac);
if( res!=RES_OK )
goto exit_label;
for(k = 0; k < n; k++)
{
res = polyval_cmplx(bc, ord, s+k, 1, &num);
if(res != RES_OK)
goto exit_label;
res = polyval_cmplx(ac, ord, s+k, 1, &den);
if(res != RES_OK)
goto exit_label;
mag = ABSSQR(den);
if(mag == 0.0)
{
res = ERROR_DIV_ZERO;
goto exit_label;
}
mag = 1.0 / mag;
RE(h[k]) = CMCONJRE(num, den) * mag;
IM(h[k]) = CMCONJIM(num, den) * mag;
}
res = RES_OK;
exit_label:
if(bc)
free(bc);
if(ac)
free(ac);
return res;
}