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comparison spandsp-0.0.3/spandsp-0.0.3/src/spandsp/sig_tone.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 * sig_tone.h - Signalling tone processing for the 2280Hz, 2600Hz and similar
5 * signalling tone used in older protocols.
6 *
7 * Written by Steve Underwood <steveu@coppice.org>
8 *
9 * Copyright (C) 2004 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: sig_tone.h,v 1.7 2006/10/24 13:22:02 steveu Exp $
27 */
28
29 /*! \file */
30
31 /*! \page sig_tone_page The signaling tone processor
32 \section sig_tone_sec_1 What does it do?
33 The signaling tone processor handles the 2280Hz, 2400Hz and 2600Hz tones, used
34 in many analogue signaling procotols, and digital ones derived from them.
35
36 \section sig_tone_sec_2 How does it work?
37 TBD
38 */
39
40 #if !defined(_SIG_TONE_H_)
41 #define _SIG_TONE_H_
42
43 typedef int (*sig_tone_func_t)(void *user_data, int what);
44
45 /* The optional tone sets */
46 enum
47 {
48 SIG_TONE_2280HZ = 1,
49 SIG_TONE_2600HZ,
50 SIG_TONE_2400HZ_2600HZ
51 };
52
53 #define SIG_TONE_1_PRESENT 0x001
54 #define SIG_TONE_1_CHANGE 0x002
55 #define SIG_TONE_2_PRESENT 0x004
56 #define SIG_TONE_2_CHANGE 0x008
57 #define SIG_TONE_TX_PASSTHROUGH 0x010
58 #define SIG_TONE_RX_PASSTHROUGH 0x020
59 #define SIG_TONE_UPDATE_REQUEST 0x100
60
61 /*!
62 Signaling tone descriptor. This defines the working state for a
63 single instance of the transmit and receive sides of a signaling
64 tone processor.
65 */
66 typedef struct
67 {
68 /*! \brief The tones used. */
69 int tone_freq[2];
70 /*! \brief The high and low tone amplitudes. */
71 int tone_amp[2];
72
73 /*! \brief The delay, in audio samples, before the high level tone drops
74 to a low level tone. */
75 int high_low_timeout;
76
77 /*! \brief Some signaling tone detectors use a sharp initial filter,
78 changing to a broader band filter after some delay. This
79 parameter defines the delay. 0 means it never changes. */
80 int sharp_flat_timeout;
81
82 /*! \brief Parameters to control the behaviour of the notch filter, used
83 to remove the tone from the voice path in some protocols. */
84 int notch_lag_time;
85 int notch_allowed;
86
87 /*! \brief The tone on persistence check, in audio samples. */
88 int tone_on_check_time;
89 /*! \brief The tone off persistence check, in audio samples. */
90 int tone_off_check_time;
91
92 /*! \brief The coefficients for the cascaded bi-quads notch filter. */
93 int32_t notch_a1[3];
94 int32_t notch_b1[3];
95 int32_t notch_a2[3];
96 int32_t notch_b2[3];
97 int notch_postscale;
98
99 /*! \brief Flat mode bandpass bi-quad parameters */
100 int32_t broad_a[3];
101 int32_t broad_b[3];
102 int broad_postscale;
103
104 /*! \brief The coefficients for the post notch leaky integrator. */
105 int32_t notch_slugi;
106 int32_t notch_slugp;
107
108 /*! \brief The coefficients for the post modulus leaky integrator in the
109 unfiltered data path. The prescale value incorporates the
110 detection ratio. This is called the guard ratio in some
111 protocols. */
112 int32_t unfiltered_slugi;
113 int32_t unfiltered_slugp;
114
115 /*! \brief The coefficients for the post modulus leaky integrator in the
116 bandpass filter data path. */
117 int32_t broad_slugi;
118 int32_t broad_slugp;
119
120 /*! \brief Masks which effectively threshold the notched, weighted and
121 bandpassed data. */
122 int32_t notch_threshold;
123 int32_t unfiltered_threshold;
124 int32_t broad_threshold;
125 } sig_tone_descriptor_t;
126
127 typedef struct
128 {
129 /*! \brief The callback function used to handle signaling changes. */
130 sig_tone_func_t sig_update;
131 /*! \brief A user specified opaque pointer passed to the callback function. */
132 void *user_data;
133
134 /*! \brief Transmit side parameters */
135 sig_tone_descriptor_t *desc;
136 int32_t phase_rate[2];
137 int32_t tone_scaling[2];
138 uint32_t phase_acc[2];
139
140 int high_low_timer;
141
142 /*! \brief The z's for the notch filter */
143 int32_t notch_z1[3];
144 int32_t notch_z2[3];
145
146 /*! \brief The z's for the weighting/bandpass filter. */
147 int32_t broad_z[3];
148
149 /*! \brief The z's for the integrators. */
150 int32_t notch_zl;
151 int32_t broad_zl;
152
153 /*! \brief The thresholded data. */
154 int32_t mown_notch;
155 int32_t mown_bandpass;
156
157 int flat_mode;
158 int tone_present;
159 int notch_enabled;
160 int flat_mode_timeout;
161 int notch_insertion_timeout;
162 int tone_persistence_timeout;
163
164 int current_tx_tone;
165 int current_tx_timeout;
166 int signaling_state_duration;
167 } sig_tone_state_t;
168
169 /*! Initialise a signaling tone context.
170 \brief Initialise a signaling tone context.
171 \param s The signaling tone context.
172 \param tone_type The type of signaling tone.
173 \param sig_update Callback function to handle signaling updates.
174 \param user_data An opaque pointer.
175 \return A pointer to the signalling tone context, or NULL if there was a problem. */
176 sig_tone_state_t *sig_tone_init(sig_tone_state_t *s, int tone_type, sig_tone_func_t sig_update, void *user_data);
177
178 /*! Process a block of received audio samples.
179 \brief Process a block of received audio samples.
180 \param s The signaling tone context.
181 \param amp The audio sample buffer.
182 \param len The number of samples in the buffer.
183 \return The number of samples unprocessed. */
184 int sig_tone_rx(sig_tone_state_t *s, int16_t amp[], int len);
185
186 /*! Generate a block of signaling tone audio samples.
187 \brief Generate a block of signaling tone audio samples.
188 \param s The signaling tone context.
189 \param amp The audio sample buffer.
190 \param len The number of samples to be generated.
191 \return The number of samples actually generated. */
192 int sig_tone_tx(sig_tone_state_t *s, int16_t amp[], int len);
193
194 #endif
195 /*- End of file ------------------------------------------------------------*/

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