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5
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1 /*
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2 * SpanDSP - a series of DSP components for telephony
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3 *
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4 * complex_filters.h
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5 *
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6 * Written by Steve Underwood <steveu@coppice.org>
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7 *
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8 * Copyright (C) 2003 Steve Underwood
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9 *
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10 * All rights reserved.
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11 *
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12 * This program is free software; you can redistribute it and/or modify
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13 * it under the terms of the GNU General Public License version 2, as
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14 * published by the Free Software Foundation.
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15 *
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16 * This program is distributed in the hope that it will be useful,
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17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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19 * GNU General Public License for more details.
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20 *
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21 * You should have received a copy of the GNU General Public License
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22 * along with this program; if not, write to the Free Software
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23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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24 *
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25 * $Id: complex_filters.h,v 1.6 2006/10/24 13:45:28 steveu Exp $
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26 */
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27
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28 #if !defined(_COMPLEX_FILTERS_H_)
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29 #define _COMPLEX_FILTERS_H_
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30
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31 typedef struct filter_s filter_t;
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32
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33 typedef float (*filter_step_func_t)(filter_t *fi, float x);
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34
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35 typedef struct
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36 {
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37 int nz;
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38 int np;
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39 filter_step_func_t fsf;
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40 } fspec_t;
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41
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42 struct filter_s
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43 {
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44 fspec_t *fs;
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45 float sum;
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46 int ptr; /* for moving average filters only */
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47 float v[];
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48 };
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49
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50 typedef struct
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51 {
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52 filter_t *ref;
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53 filter_t *imf;
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54 } cfilter_t;
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55
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56 #ifdef __cplusplus
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57 extern "C" {
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58 #endif
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59
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60 filter_t *filter_create(fspec_t *fs);
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61 void filter_delete(filter_t *fi);
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62 float filter_step(filter_t *fi, float x);
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63
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64 cfilter_t *cfilter_create(fspec_t *fs);
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65 void cfilter_delete(cfilter_t *cfi);
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66 complexf_t cfilter_step(cfilter_t *cfi, const complexf_t *z);
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67
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68 #ifdef __cplusplus
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69 }
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70 #endif
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71
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72 #endif
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73 /*- End of file ------------------------------------------------------------*/
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