File indexing completed on 2024-05-12 15:27:07
0001 /*************************************************************************** 0002 File : nsl_filter.h 0003 Project : LabPlot 0004 Description : NSL Fourier filter functions 0005 -------------------------------------------------------------------- 0006 Copyright : (C) 2016 by Stefan Gerlach (stefan.gerlach@uni.kn) 0007 0008 ***************************************************************************/ 0009 0010 /*************************************************************************** 0011 * * 0012 * This program is free software; you can redistribute it and/or modify * 0013 * it under the terms of the GNU General Public License as published by * 0014 * the Free Software Foundation; either version 2 of the License, or * 0015 * (at your option) any later version. * 0016 * * 0017 * This program is distributed in the hope that it will be useful, * 0018 * but WITHOUT ANY WARRANTY; without even the implied warranty of * 0019 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * 0020 * GNU General Public License for more details. * 0021 * * 0022 * You should have received a copy of the GNU General Public License * 0023 * along with this program; if not, write to the Free Software * 0024 * Foundation, Inc., 51 Franklin Street, Fifth Floor, * 0025 * Boston, MA 02110-1301 USA * 0026 * * 0027 ***************************************************************************/ 0028 0029 #ifndef NSL_FILTER_H 0030 #define NSL_FILTER_H 0031 0032 #include <stdlib.h> 0033 0034 #define NSL_FILTER_TYPE_COUNT 4 0035 typedef enum {nsl_filter_type_low_pass, nsl_filter_type_high_pass, nsl_filter_type_band_pass, 0036 nsl_filter_type_band_reject} nsl_filter_type; /*TODO: Threshold */ 0037 extern const char* nsl_filter_type_name[]; 0038 #define NSL_FILTER_FORM_COUNT 6 0039 typedef enum {nsl_filter_form_ideal, nsl_filter_form_butterworth, nsl_filter_form_chebyshev_i, 0040 nsl_filter_form_chebyshev_ii, nsl_filter_form_legendre, nsl_filter_form_bessel} nsl_filter_form; 0041 extern const char* nsl_filter_form_name[]; 0042 /* unit for cutoff 0043 Frequency=0..f_max, Fraction=0..1, Index=0..N-1 0044 */ 0045 #define NSL_FILTER_CUTOFF_UNIT_COUNT 3 0046 typedef enum {nsl_filter_cutoff_unit_frequency, nsl_filter_cutoff_unit_fraction, 0047 nsl_filter_cutoff_unit_index} nsl_filter_cutoff_unit; 0048 extern const char* nsl_filter_cutoff_unit_name[]; 0049 0050 /* Gain G(x) for Bessel filter */ 0051 double nsl_filter_gain_bessel(int n, double x); 0052 0053 int nsl_filter_apply(double data[], size_t n, nsl_filter_type type, nsl_filter_form form, int order, double cutindex, double bandwidth); 0054 int nsl_filter_fourier(double data[], size_t n, nsl_filter_type type, nsl_filter_form form, int order, int cutindex, int bandwidth); 0055 0056 #endif /* NSL_FILTER_H */