kopia lustrzana https://github.com/Dsplib/libdspl-2.0
added functions for butterworth filter
Dsplib
rodzic
032d4cba74
commit
5dfdb06091
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@ -1,71 +0,0 @@
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/*
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* Copyright (c) 2015-2018 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 "dspl.h"
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/**************************************************************************************************
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Zeros and poles to filter coefficients recalc
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***************************************************************************************************/
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int DSPL_API filter_zp2ab(complex_t *z, int nz, complex_t *p, int np, int ord, double* b, double* a)
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{
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complex_t *acc = NULL;
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int res;
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if(!z || !p || !b || !a)
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return ERROR_PTR;
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if(nz < 0 || np < 0)
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return ERROR_SIZE;
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if(nz < ord || np < ord)
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return ERROR_POLY_ORD;
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acc = (complex_t*) malloc((ord+1) * sizeof(complex_t));
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res = poly_z2a_cmplx(z, nz, ord, acc);
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if(res != RES_OK)
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goto exit_label;
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res = cmplx2re(acc, ord+1, b, NULL);
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if(res != RES_OK)
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goto exit_label;
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res = poly_z2a_cmplx(p, np, ord, acc);
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if(res != RES_OK)
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goto exit_label;
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res = cmplx2re(acc, ord+1, a, NULL);
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if(res != RES_OK)
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goto exit_label;
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exit_label:
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if(acc)
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free(acc);
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return res;
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}
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@ -0,0 +1,168 @@
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/*
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* Copyright (c) 2015-2018 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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/**************************************************************************************************
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Analog Normalized Butterworth filter
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***************************************************************************************************/
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int DSPL_API butter_ap(double Rp, int ord, double* b, double* a)
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{
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int res;
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complex_t *z = NULL;
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complex_t *p = NULL;
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int nz, np;
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if(Rp < 0.0)
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return ERROR_FILTER_RP;
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if(ord < 1)
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return ERROR_FILTER_ORD;
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if(!a || !b)
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return ERROR_PTR;
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z = (complex_t*) malloc(ord*sizeof(complex_t));
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p = (complex_t*) malloc(ord*sizeof(complex_t));
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res = butter_ap_zp(ord, Rp, z, &nz, p, &np);
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if(res != RES_OK)
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goto exit_label;
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res = filter_zp2ab(z, nz, p, np, ord, b, a);
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if(res != RES_OK)
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goto exit_label;
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b[0] = a[0];
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exit_label:
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if(z)
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free(z);
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if(p)
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free(p);
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return res;
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}
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/**************************************************************************************************
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Analog Normalized Butterworth filter zeros and poles
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***************************************************************************************************/
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int DSPL_API butter_ap_zp(int ord, double rp, complex_t *z, int* nz, complex_t *p, int* np)
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{
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double alpha;
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double theta;
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double ep;
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int r;
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int L;
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int ind = 0, k;
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if(rp < 0 || rp == 0)
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return ERROR_FILTER_RP;
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if(ord < 1)
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return ERROR_FILTER_ORD;
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if(!z || !p || !nz || !np)
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return ERROR_PTR;
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ep = sqrt(pow(10.0, rp*0.1) - 1.0);
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r = ord % 2;
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L = (int)((ord-r)/2);
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alpha = pow(ep, -1.0/(double)ord);
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if(r)
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{
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RE(p[ind]) = -alpha;
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IM(p[ind]) = 0.0;
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ind++;
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}
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for(k = 0; k < L; k++)
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{
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theta = M_PI*(double)(2*k + 1)/(double)(2*ord);
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RE(p[ind]) = RE(p[ind+1]) = -alpha * sin(theta);
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IM(p[ind]) = alpha * cos(theta);
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IM(p[ind+1]) = -alpha * cos(theta);
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ind+=2;
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}
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*np = ord;
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*nz = 0;
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return RES_OK;
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}
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/**************************************************************************************************
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Zeros and poles to filter coefficients recalc
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***************************************************************************************************/
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int DSPL_API filter_zp2ab(complex_t *z, int nz, complex_t *p, int np, int ord, double* b, double* a)
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{
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complex_t *acc = NULL;
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int res;
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if(!z || !p || !b || !a)
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return ERROR_PTR;
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if(nz < 0 || np < 0)
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return ERROR_SIZE;
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if(nz > ord || np > ord)
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return ERROR_POLY_ORD;
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acc = (complex_t*) malloc((ord+1) * sizeof(complex_t));
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res = poly_z2a_cmplx(z, nz, ord, acc);
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if(res != RES_OK)
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goto exit_label;
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res = cmplx2re(acc, ord+1, b, NULL);
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if(res != RES_OK)
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goto exit_label;
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res = poly_z2a_cmplx(p, np, ord, acc);
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if(res != RES_OK)
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goto exit_label;
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res = cmplx2re(acc, ord+1, a, NULL);
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if(res != RES_OK)
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goto exit_label;
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exit_label:
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if(acc)
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free(acc);
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return res;
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}
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@ -35,7 +35,7 @@ int DSPL_API poly_z2a_cmplx(complex_t* z, int nz, int ord, complex_t* a)
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if(!z || !a)
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return ERROR_PTR;
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if(nz < 1)
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if(nz < 0)
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return ERROR_SIZE;
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if(nz > ord || ord < 1)
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return ERROR_POLY_ORD;
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@ -35,10 +35,10 @@
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#ifndef BUILD_LIB
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p_acos_cmplx acos_cmplx ;
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p_asin_cmplx asin_cmplx ;
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p_butter_ap butter_ap ;
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p_butter_ap_zp butter_ap_zp ;
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p_cheby_poly1 cheby_poly1 ;
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p_cheby_poly2 cheby_poly2 ;
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p_cmplx2re cmplx2re ;
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@ -134,7 +134,9 @@ void* dspl_load()
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#endif //LINUX_OS
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LOAD_FUNC(acos_cmplx);
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LOAD_FUNC(asin_cmplx);
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LOAD_FUNC(asin_cmplx);
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LOAD_FUNC(butter_ap);
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LOAD_FUNC(butter_ap_zp);
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LOAD_FUNC(cheby_poly1);
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LOAD_FUNC(cheby_poly2);
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LOAD_FUNC(cmplx2re);
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@ -194,8 +194,12 @@ extern "C" {
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DECLARE_FUNC(int, acos_cmplx, complex_t* COMMA int COMMA complex_t*);
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DECLARE_FUNC(int, asin_cmplx, complex_t* COMMA int COMMA complex_t*);
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DECLARE_FUNC(int, cheby_poly1, double* COMMA int COMMA int COMMA double*);
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DECLARE_FUNC(int, cheby_poly2, double* COMMA int COMMA int COMMA double*);
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DECLARE_FUNC(int, butter_ap, double COMMA int COMMA double* COMMA double*);
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DECLARE_FUNC(int, butter_ap_zp, int COMMA double COMMA complex_t* COMMA int* COMMA complex_t* COMMA int*);
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DECLARE_FUNC(int, cheby_poly1, double* COMMA int COMMA int COMMA double*);
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DECLARE_FUNC(int, cheby_poly2, double* COMMA int COMMA int COMMA double*);
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DECLARE_FUNC(int, cmplx2re, complex_t* COMMA int COMMA double* COMMA double*);
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DECLARE_FUNC(int, concat, void* COMMA size_t COMMA void* COMMA size_t COMMA void*);
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DECLARE_FUNC(int, conv, double* COMMA int COMMA double* COMMA int COMMA double*);
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@ -35,10 +35,10 @@
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#ifndef BUILD_LIB
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p_acos_cmplx acos_cmplx ;
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p_asin_cmplx asin_cmplx ;
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p_butter_ap butter_ap ;
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p_butter_ap_zp butter_ap_zp ;
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p_cheby_poly1 cheby_poly1 ;
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p_cheby_poly2 cheby_poly2 ;
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p_cmplx2re cmplx2re ;
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@ -134,7 +134,9 @@ void* dspl_load()
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#endif //LINUX_OS
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LOAD_FUNC(acos_cmplx);
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LOAD_FUNC(asin_cmplx);
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LOAD_FUNC(asin_cmplx);
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LOAD_FUNC(butter_ap);
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LOAD_FUNC(butter_ap_zp);
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LOAD_FUNC(cheby_poly1);
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LOAD_FUNC(cheby_poly2);
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LOAD_FUNC(cmplx2re);
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@ -194,8 +194,12 @@ extern "C" {
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DECLARE_FUNC(int, acos_cmplx, complex_t* COMMA int COMMA complex_t*);
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DECLARE_FUNC(int, asin_cmplx, complex_t* COMMA int COMMA complex_t*);
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DECLARE_FUNC(int, cheby_poly1, double* COMMA int COMMA int COMMA double*);
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DECLARE_FUNC(int, cheby_poly2, double* COMMA int COMMA int COMMA double*);
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DECLARE_FUNC(int, butter_ap, double COMMA int COMMA double* COMMA double*);
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DECLARE_FUNC(int, butter_ap_zp, int COMMA double COMMA complex_t* COMMA int* COMMA complex_t* COMMA int*);
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DECLARE_FUNC(int, cheby_poly1, double* COMMA int COMMA int COMMA double*);
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DECLARE_FUNC(int, cheby_poly2, double* COMMA int COMMA int COMMA double*);
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DECLARE_FUNC(int, cmplx2re, complex_t* COMMA int COMMA double* COMMA double*);
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DECLARE_FUNC(int, concat, void* COMMA size_t COMMA void* COMMA size_t COMMA void*);
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DECLARE_FUNC(int, conv, double* COMMA int COMMA double* COMMA int COMMA double*);
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Plik binarny nie jest wyświetlany.
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@ -0,0 +1,7 @@
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set logscale x
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unset key
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set grid
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set xlabel "frequency, rad/s"
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set ylabel "Butterworth filter magnitude, dB"
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plot 'dat/butter_ap_test_mag.txt' with lines
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Plik binarny nie jest wyświetlany.
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Po Szerokość: | Wysokość: | Rozmiar: 23 KiB |
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@ -0,0 +1,44 @@
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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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#define ORD 4
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#define N 1000
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int main()
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{
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void* handle; // DSPL handle
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handle = dspl_load(); // Load DSPL function
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double a[ORD+1], b[ORD+1];
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double Rp = 3.0;
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int k;
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int res = butter_ap(Rp, ORD, b, a);
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if(res != RES_OK)
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printf("error code = 0x%8x\n", res);
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for(k = 0; k < ORD+1; k++)
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printf("b[%2d] = %9.3f a[%2d] = %9.3f\n", k, b[k], k, a[k]);
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double w[N], hdb[N];
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complex_t h[N];
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logspace(-2.0, 2.0, N , DSPL_SYMMETRIC, w);
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freqs(b, a, ORD, w, N, h);
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for(k = 0; k < N; k++)
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hdb[k] = 10.0 * log10(ABSSQR(h[k]));
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writetxt(w, hdb, N, "dat/butter_ap_test_mag.txt");
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dspl_free(handle); // free dspl handle
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system("gnuplot -p gnuplot/butter_ap_test.plt");
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return 0;
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}
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