Mercurial > hg > audiostuff
comparison spandsp-0.0.3/spandsp-0.0.3/src/tone_detect.c @ 5:f762bf195c4b
import spandsp-0.0.3
| author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
|---|---|
| date | Fri, 25 Jun 2010 16:00:21 +0200 |
| parents | |
| children |
comparison
equal
deleted
inserted
replaced
| 4:26cd8f1ef0b1 | 5:f762bf195c4b |
|---|---|
| 1 /* | |
| 2 * SpanDSP - a series of DSP components for telephony | |
| 3 * | |
| 4 * tone_detect.c - General telephony tone detection, and specific | |
| 5 * detection of Bell MF, and MFC/R2. | |
| 6 * | |
| 7 * Written by Steve Underwood <steveu@coppice.org> | |
| 8 * | |
| 9 * Copyright (C) 2001-2003, 2005 Steve Underwood | |
| 10 * | |
| 11 * All rights reserved. | |
| 12 * | |
| 13 * This program is free software; you can redistribute it and/or modify | |
| 14 * it under the terms of the GNU General Public License version 2, as | |
| 15 * published by the Free Software Foundation. | |
| 16 * | |
| 17 * This program is distributed in the hope that it will be useful, | |
| 18 * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 20 * GNU General Public License for more details. | |
| 21 * | |
| 22 * You should have received a copy of the GNU General Public License | |
| 23 * along with this program; if not, write to the Free Software | |
| 24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
| 25 * | |
| 26 * $Id: tone_detect.c,v 1.30 2006/11/19 14:07:25 steveu Exp $ | |
| 27 */ | |
| 28 | |
| 29 /*! \file tone_detect.h */ | |
| 30 | |
| 31 #ifdef HAVE_CONFIG_H | |
| 32 #include "config.h" | |
| 33 #endif | |
| 34 | |
| 35 #include <inttypes.h> | |
| 36 #include <stdlib.h> | |
| 37 #if defined(HAVE_TGMATH_H) | |
| 38 #include <tgmath.h> | |
| 39 #endif | |
| 40 #if defined(HAVE_MATH_H) | |
| 41 #include <math.h> | |
| 42 #endif | |
| 43 #include <string.h> | |
| 44 #include <stdio.h> | |
| 45 #include <time.h> | |
| 46 #include <fcntl.h> | |
| 47 | |
| 48 #include "spandsp/telephony.h" | |
| 49 #include "spandsp/tone_detect.h" | |
| 50 #include "spandsp/tone_generate.h" | |
| 51 | |
| 52 #if !defined(M_PI) | |
| 53 /* C99 systems may not define M_PI */ | |
| 54 #define M_PI 3.14159265358979323846264338327 | |
| 55 #endif | |
| 56 | |
| 57 void make_goertzel_descriptor(goertzel_descriptor_t *t, float freq, int samples) | |
| 58 { | |
| 59 t->fac = 2.0f*cosf(2.0f*M_PI*(freq/(float) SAMPLE_RATE)); | |
| 60 t->samples = samples; | |
| 61 } | |
| 62 /*- End of function --------------------------------------------------------*/ | |
| 63 | |
| 64 goertzel_state_t *goertzel_init(goertzel_state_t *s, | |
| 65 goertzel_descriptor_t *t) | |
| 66 { | |
| 67 if (s || (s = malloc(sizeof(goertzel_state_t)))) | |
| 68 { | |
| 69 s->v2 = | |
| 70 s->v3 = 0.0; | |
| 71 s->fac = t->fac; | |
| 72 s->samples = t->samples; | |
| 73 s->current_sample = 0; | |
| 74 } | |
| 75 return s; | |
| 76 } | |
| 77 /*- End of function --------------------------------------------------------*/ | |
| 78 | |
| 79 void goertzel_reset(goertzel_state_t *s) | |
| 80 { | |
| 81 s->v2 = | |
| 82 s->v3 = 0.0; | |
| 83 s->current_sample = 0; | |
| 84 } | |
| 85 /*- End of function --------------------------------------------------------*/ | |
| 86 | |
| 87 int goertzel_update(goertzel_state_t *s, | |
| 88 const int16_t amp[], | |
| 89 int samples) | |
| 90 { | |
| 91 int i; | |
| 92 float v1; | |
| 93 | |
| 94 if (samples > s->samples - s->current_sample) | |
| 95 samples = s->samples - s->current_sample; | |
| 96 for (i = 0; i < samples; i++) | |
| 97 { | |
| 98 v1 = s->v2; | |
| 99 s->v2 = s->v3; | |
| 100 s->v3 = s->fac*s->v2 - v1 + amp[i]; | |
| 101 } | |
| 102 s->current_sample += samples; | |
| 103 return samples; | |
| 104 } | |
| 105 /*- End of function --------------------------------------------------------*/ | |
| 106 | |
| 107 float goertzel_result(goertzel_state_t *s) | |
| 108 { | |
| 109 float v1; | |
| 110 | |
| 111 /* Push a zero through the process to finish things off. */ | |
| 112 v1 = s->v2; | |
| 113 s->v2 = s->v3; | |
| 114 s->v3 = s->fac*s->v2 - v1; | |
| 115 /* Now calculate the non-recursive side of the filter. */ | |
| 116 /* The result here is not scaled down to allow for the magnification | |
| 117 effect of the filter (the usual DFT magnification effect). */ | |
| 118 return s->v3*s->v3 + s->v2*s->v2 - s->v2*s->v3*s->fac; | |
| 119 } | |
| 120 /*- End of function --------------------------------------------------------*/ | |
| 121 /*- End of file ------------------------------------------------------------*/ |