kopia lustrzana https://github.com/Dsplib/libdspl-2.0
59 wiersze
1.5 KiB
C
59 wiersze
1.5 KiB
C
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/*
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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 <stdio.h>
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#include <stdlib.h>
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#include <string.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 cheby2_ap_wp1(double rp, double rs, int ord, double* b, double* a)
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{
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int err;
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double es, gp, alpha, beta, y, wp;
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if(rp <= 0)
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return ERROR_FILTER_RP;
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err = cheby2_ap(rs, ord, b, a);
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if(err!=RES_OK)
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goto exit_label;
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es = sqrt(pow(10.0, rs*0.1) - 1.0);
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gp = pow(10.0, -rp*0.05);
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alpha = gp * es / sqrt(1.0 - gp*gp);
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beta = alpha + sqrt(alpha * alpha - 1.0);
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y = log(beta)/ (double)ord;
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wp = 2.0 / (exp(y) + exp(-y));
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err = low2low(b, a, ord, wp, 1.0, b, a);
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exit_label:
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return err;
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}
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