Mercurial > hg > audiostuff
comparison spandsp-0.0.3/spandsp-0.0.3/src/spandsp/tone_generate.h @ 5:f762bf195c4b
import spandsp-0.0.3
| author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
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| date | Fri, 25 Jun 2010 16:00:21 +0200 |
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| 4:26cd8f1ef0b1 | 5:f762bf195c4b |
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| 1 /* | |
| 2 * SpanDSP - a series of DSP components for telephony | |
| 3 * | |
| 4 * tone_generate.h - General telephony tone generation, and specific | |
| 5 * generation of Bell MF, MFC/R2 and network supervisory tones. | |
| 6 * | |
| 7 * Written by Steve Underwood <steveu@coppice.org> | |
| 8 * | |
| 9 * Copyright (C) 2001 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_generate.h,v 1.24 2006/11/24 12:34:55 steveu Exp $ | |
| 27 */ | |
| 28 | |
| 29 /*! \file */ | |
| 30 | |
| 31 #if !defined(_TONE_GENERATE_H_) | |
| 32 #define _TONE_GENERATE_H_ | |
| 33 | |
| 34 /*! \page tone_generation_page Tone generation | |
| 35 \section tone_generation_page_sec_1 What does it do? | |
| 36 The tone generation module provides for the generation of cadenced tones, | |
| 37 suitable for a wide range of telephony applications. | |
| 38 | |
| 39 \section tone_generation_page_sec_2 How does it work? | |
| 40 Oscillators are a problem. They oscillate due to instability, and yet we need | |
| 41 them to behave in a stable manner. A look around the web will reveal many papers | |
| 42 on this subject. Many describe rather complex solutions to the problem. However, | |
| 43 we are only concerned with telephony applications. It is possible to generate | |
| 44 the tones we need with a very simple efficient scheme. It is also practical to | |
| 45 use an exhaustive test to prove the oscillator is stable under all the | |
| 46 conditions in which we will use it. | |
| 47 */ | |
| 48 | |
| 49 /*! | |
| 50 Cadenced dual tone generator descriptor. | |
| 51 */ | |
| 52 typedef struct | |
| 53 { | |
| 54 int32_t phase_rate[2]; | |
| 55 float gain[2]; | |
| 56 int modulate; | |
| 57 | |
| 58 int duration[4]; | |
| 59 | |
| 60 int repeat; | |
| 61 } tone_gen_descriptor_t; | |
| 62 | |
| 63 /*! | |
| 64 Cadenced dual tone generator state descriptor. This defines the state of | |
| 65 a single working instance of a generator. | |
| 66 */ | |
| 67 typedef struct | |
| 68 { | |
| 69 int32_t phase_rate[2]; | |
| 70 float gain[2]; | |
| 71 int modulate; | |
| 72 | |
| 73 uint32_t phase[2]; | |
| 74 | |
| 75 int duration[4]; | |
| 76 | |
| 77 int repeat; | |
| 78 | |
| 79 int current_section; | |
| 80 int current_position; | |
| 81 } tone_gen_state_t; | |
| 82 | |
| 83 typedef struct | |
| 84 { | |
| 85 /*! First freq */ | |
| 86 int f1; | |
| 87 /*! Second freq. 0 for none. Negative for an AM modulation tone. */ | |
| 88 int f2; | |
| 89 /*! Level of the first freq (dBm0) */ | |
| 90 int8_t level1; | |
| 91 /*! Level of the second freq (dBm0), or % modulation for AM */ | |
| 92 int8_t level2; | |
| 93 /*! Tone on time (ms) */ | |
| 94 uint16_t on_time1; | |
| 95 /*! Minimum post tone silence (ms) */ | |
| 96 uint16_t off_time1; | |
| 97 /*! Tone on time (ms) */ | |
| 98 uint16_t on_time2; | |
| 99 /*! Minimum post tone silence (ms) */ | |
| 100 uint16_t off_time2; | |
| 101 /*! TRUE if cyclic tone, FALSE for one shot. */ | |
| 102 int8_t repeat; | |
| 103 } cadenced_tone_t; | |
| 104 | |
| 105 #ifdef __cplusplus | |
| 106 extern "C" { | |
| 107 #endif | |
| 108 | |
| 109 void make_tone_descriptor(tone_gen_descriptor_t *desc, cadenced_tone_t *tone); | |
| 110 | |
| 111 /*! Create a tone generator descriptor | |
| 112 \brief Create a tone generator descriptor | |
| 113 \param s The descriptor | |
| 114 \param f1 The first frequency, in Hz | |
| 115 \param l1 The level of the first frequency, in dBm0 | |
| 116 \param f2 0 for no second frequency, a positive number for the second frequency, | |
| 117 in Hz, or a negative number for an AM modulation frequency, in Hz | |
| 118 \param l2 The level of the second frequency, in dBm0, or the percentage modulation depth | |
| 119 for an AM modulated tone. | |
| 120 \param d1 x | |
| 121 \param d2 x | |
| 122 \param d3 x | |
| 123 \param d4 x | |
| 124 \param repeat x */ | |
| 125 void make_tone_gen_descriptor(tone_gen_descriptor_t *s, | |
| 126 int f1, | |
| 127 int l1, | |
| 128 int f2, | |
| 129 int l2, | |
| 130 int d1, | |
| 131 int d2, | |
| 132 int d3, | |
| 133 int d4, | |
| 134 int repeat); | |
| 135 | |
| 136 void tone_gen_init(tone_gen_state_t *s, tone_gen_descriptor_t *t); | |
| 137 | |
| 138 int tone_gen(tone_gen_state_t *s, int16_t amp[], int max_samples); | |
| 139 | |
| 140 #ifdef __cplusplus | |
| 141 } | |
| 142 #endif | |
| 143 | |
| 144 #endif | |
| 145 /*- End of file ------------------------------------------------------------*/ |