kopia lustrzana https://github.com/Dsplib/libdspl-2.0
93 wiersze
2.1 KiB
C
93 wiersze
2.1 KiB
C
/*
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* Copyright (c) 2015-2019 Sergey Bakhurin
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* Digital Signal Processing Library [http://dsplib.org]
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*
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* This file is part of libdspl-2.0.
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*
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* is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* DSPL is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with Foobar. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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#include "dspl.h"
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#ifdef DOXYGEN_ENGLISH
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#endif
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#ifdef DOXYGEN_RUSSIAN
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#endif
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int DSPL_API freqs2time(double* b, double* a, int ord, double fs,
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int n, fft_t* pfft, double *t, double *h)
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{
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double *w = NULL;
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complex_t *hs = NULL;
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complex_t *ht = NULL;
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int err, k;
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if(!b || !a || !t || !h)
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return ERROR_PTR;
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if(ord<1)
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return ERROR_FILTER_ORD;
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if(n<1)
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return ERROR_SIZE;
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w = (double*)malloc(n*sizeof(double));
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hs = (complex_t*)malloc(n*sizeof(complex_t));
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err = linspace(-fs*0.5, fs*0.5, n, DSPL_PERIODIC, w);
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if(err != RES_OK)
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goto exit_label;
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err = freqs(b, a, ord, w, n, hs);
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if(err != RES_OK)
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goto exit_label;
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err = fft_shift_cmplx(hs, n, hs);
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if(err != RES_OK)
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goto exit_label;
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ht = (complex_t*)malloc(n*sizeof(complex_t));
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err = ifft_cmplx(hs, n, pfft, ht);
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if(err != RES_OK)
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{
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err = idft_cmplx(hs, n, ht);
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if(err != RES_OK)
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goto exit_label;
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}
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for(k = 0; k < n; k++)
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{
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t[k] = (double)k/fs;
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h[k] = RE(ht[k]) * fs;
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}
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exit_label:
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if(w)
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free(w);
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if(hs)
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free(hs);
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if(ht)
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free(ht);
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return err;
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}
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