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comparison spandsp-0.0.3/spandsp-0.0.3/src/spandsp/super_tone_tx.h @ 5:f762bf195c4b

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import spandsp-0.0.3
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 16:00:21 +0200
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4:26cd8f1ef0b1 5:f762bf195c4b
1 /*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * super_tone_tx.h - Flexible telephony supervisory tone generation.
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2001 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2, as
14 * published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25 * $Id: super_tone_tx.h,v 1.8 2006/10/24 13:45:28 steveu Exp $
26 */
27
28 #if !defined(_SUPER_TONE_TX_H_)
29 #define _SUPER_TONE_TX_H_
30
31 /*! \page super_tone_tx_page Supervisory tone generation
32
33 \section super_tone_tx_page_sec_1 What does it do?
34
35 The supervisory tone generator may be configured to generate most of the world's
36 telephone supervisory tones - things like ringback, busy, number unobtainable,
37 and so on. It uses tree structure tone descriptions, which can deal with quite
38 complex cadence patterns.
39
40 \section super_tone_tx_page_sec_2 How does it work?
41
42 */
43
44 typedef struct super_tone_tx_step_s super_tone_tx_step_t;
45
46 typedef struct
47 {
48 int32_t phase_rate[2];
49 float gain[2];
50 uint32_t phase[2];
51 int current_position;
52 int level;
53 super_tone_tx_step_t *levels[4];
54 int cycles[4];
55 } super_tone_tx_state_t;
56
57 struct super_tone_tx_step_s
58 {
59 int32_t phase_rate[2];
60 float gain[2];
61 int tone;
62 int length;
63 int cycles;
64 super_tone_tx_step_t *next;
65 super_tone_tx_step_t *nest;
66 };
67
68 super_tone_tx_step_t *super_tone_tx_make_step(super_tone_tx_step_t *s,
69 float f1,
70 float l1,
71 float f2,
72 float l2,
73 int length,
74 int cycles);
75
76 void super_tone_tx_free(super_tone_tx_step_t *s);
77
78 /*! Initialise a supervisory tone generator.
79 \brief Initialise a supervisory tone generator.
80 \param s The supervisory tone generator context.
81 \param tree The supervisory tone tree to be generated.
82 \return The supervisory tone generator context. */
83 super_tone_tx_state_t *super_tone_tx_init(super_tone_tx_state_t *s, super_tone_tx_step_t *tree);
84
85 /*! Generate a block of audio samples for a supervisory tone pattern.
86 \brief Generate a block of audio samples for a supervisory tone pattern.
87 \param tone The supervisory tone context.
88 \param amp The audio sample buffer.
89 \param max_samples The maximum number of samples to be generated.
90 \return The number of samples generated. */
91 int super_tone_tx(super_tone_tx_state_t *s, int16_t amp[], int max_samples);
92
93 #endif
94 /*- End of file ------------------------------------------------------------*/

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