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comparison spandsp-0.0.3/spandsp-0.0.3/src/modem_connect_tones.c @ 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 * modem_connect_tones.c - Generation and detection of tones
5 * associated with modems calling and answering calls.
6 *
7 * Written by Steve Underwood <steveu@coppice.org>
8 *
9 * Copyright (C) 2006 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: modem_connect_tones.c,v 1.6 2006/11/30 15:41:47 steveu Exp $
27 */
28
29 /*! \file */
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
44 #include "spandsp/telephony.h"
45 #include "spandsp/dds.h"
46 #include "spandsp/tone_detect.h"
47 #include "spandsp/tone_generate.h"
48 #include "spandsp/super_tone_rx.h"
49 #include "spandsp/modem_connect_tones.h"
50
51 int modem_connect_tones_tx(modem_connect_tones_tx_state_t *s,
52 int16_t amp[],
53 int len)
54 {
55 int mod;
56 int i;
57
58 switch (s->tone_type)
59 {
60 case MODEM_CONNECT_TONES_FAX_CNG:
61 case MODEM_CONNECT_TONES_FAX_CED:
62 len = tone_gen(&s->tone_tx, amp, len);
63 break;
64 case MODEM_CONNECT_TONES_EC_DISABLE:
65 for (i = 0; i < len; i++)
66 {
67 if (--s->hop_timer <= 0)
68 {
69 s->hop_timer = ms_to_samples(450);
70 s->tone_phase += 0x80000000;
71 }
72 amp[i] = dds_mod(&s->tone_phase, s->tone_phase_rate, s->level, 0);
73 }
74 break;
75 case MODEM_CONNECT_TONES_EC_DISABLE_MOD:
76 for (i = 0; i < len; i++)
77 {
78 mod = s->level + dds_mod(&s->mod_phase, s->mod_phase_rate, s->mod_level, 0);
79 if (--s->hop_timer <= 0)
80 {
81 s->hop_timer = ms_to_samples(450);
82 s->tone_phase += 0x80000000;
83 }
84 amp[i] = dds_mod(&s->tone_phase, s->tone_phase_rate, mod, 0);
85 }
86 break;
87 }
88 return len;
89 }
90 /*- End of function --------------------------------------------------------*/
91
92 modem_connect_tones_tx_state_t *modem_connect_tones_tx_init(modem_connect_tones_tx_state_t *s,
93 int tone_type)
94 {
95 tone_gen_descriptor_t tone_desc;
96
97 s->tone_type = tone_type;
98 switch (s->tone_type)
99 {
100 case MODEM_CONNECT_TONES_FAX_CNG:
101 make_tone_gen_descriptor(&tone_desc,
102 1100,
103 -11,
104 0,
105 0,
106 500,
107 3000,
108 0,
109 0,
110 TRUE);
111 tone_gen_init(&s->tone_tx, &tone_desc);
112 break;
113 case MODEM_CONNECT_TONES_FAX_CED:
114 make_tone_gen_descriptor(&tone_desc,
115 2100,
116 -11,
117 0,
118 0,
119 2600,
120 0,
121 0,
122 0,
123 FALSE);
124 tone_gen_init(&s->tone_tx, &tone_desc);
125 break;
126 case MODEM_CONNECT_TONES_EC_DISABLE:
127 case MODEM_CONNECT_TONES_EC_DISABLE_MOD:
128 s->tone_phase_rate = dds_phase_rate(2100.0);
129 s->mod_phase_rate = dds_phase_rate(15.0);
130 s->tone_phase = 0;
131 s->mod_phase = 0;
132 s->hop_timer = ms_to_samples(450);
133 s->level = dds_scaling_dbm0(-12);
134 if (s->tone_type == MODEM_CONNECT_TONES_EC_DISABLE_MOD)
135 s->mod_level = s->level/5;
136 else
137 s->mod_level = 0;
138 }
139 return s;
140 }
141 /*- End of function --------------------------------------------------------*/
142
143 int modem_connect_tones_rx(modem_connect_tones_rx_state_t *s, const int16_t amp[], int len)
144 {
145 int i;
146 int16_t notched;
147 float v1;
148 float famp;
149
150 switch (s->tone_type)
151 {
152 case MODEM_CONNECT_TONES_FAX_CNG:
153 for (i = 0; i < len; i++)
154 {
155 /* A Cauer notch at 1100Hz, spread just wide enough to meet our detection bandwidth
156 criteria. */
157 famp = amp[i];
158 v1 = 0.792928f*famp + 1.0018744927985f*s->z1 - 0.54196833412465f*s->z2;
159 famp = v1 - 1.2994747954630f*s->z1 + s->z2;
160 s->z2 = s->z1;
161 s->z1 = v1;
162 notched = rintf(famp);
163
164 /* Estimate the overall energy in the channel, and the energy in
165 the notch (i.e. overall channel energy - tone energy => noise).
166 Use abs instead of multiply for speed (is it really faster?). */
167 s->channel_level += ((abs(amp[i]) - s->channel_level) >> 5);
168 s->notch_level += ((abs(notched) - s->notch_level) >> 5);
169 if (s->channel_level > 70 && s->notch_level*6 < s->channel_level)
170 {
171 /* There is adequate energy in the channel, and it is mostly at 1100Hz. */
172 if (!s->tone_present)
173 {
174 if (++s->tone_cycle_duration >= ms_to_samples(415))
175 {
176 if (s->tone_callback)
177 s->tone_callback(s->callback_data, TRUE);
178 else
179 s->hit = TRUE;
180 s->tone_present = TRUE;
181 }
182 }
183 }
184 else
185 {
186 s->tone_cycle_duration = 0;
187 }
188 }
189 break;
190 case MODEM_CONNECT_TONES_FAX_CED:
191 for (i = 0; i < len; i++)
192 {
193 /* A Cauer notch at 2100Hz, spread just wide enough to meet our detection bandwidth
194 criteria. */
195 famp = amp[i];
196 v1 = 0.76000f*famp - 0.1183852f*s->z1 - 0.5104039f*s->z2;
197 famp = v1 + 0.1567596f*s->z1 + s->z2;
198 s->z2 = s->z1;
199 s->z1 = v1;
200 notched = rintf(famp);
201 /* Estimate the overall energy in the channel, and the energy in
202 the notch (i.e. overall channel energy - tone energy => noise).
203 Use abs instead of multiply for speed (is it really faster?). */
204 s->channel_level += ((abs(amp[i]) - s->channel_level) >> 5);
205 s->notch_level += ((abs(notched) - s->notch_level) >> 5);
206 if (s->channel_level > 70 && s->notch_level*6 < s->channel_level)
207 {
208 /* There is adequate energy in the channel, and it is mostly at 2100Hz. */
209 if (!s->tone_present)
210 {
211 if (++s->tone_cycle_duration >= ms_to_samples(500))
212 {
213 if (s->tone_callback)
214 s->tone_callback(s->callback_data, TRUE);
215 else
216 s->hit = TRUE;
217 s->tone_present = TRUE;
218 }
219 }
220 }
221 else
222 {
223 s->tone_cycle_duration = 0;
224 }
225 }
226 break;
227 case MODEM_CONNECT_TONES_EC_DISABLE:
228 case MODEM_CONNECT_TONES_EC_DISABLE_MOD:
229 for (i = 0; i < len; i++)
230 {
231 /* A Cauer notch at 2100Hz, spread just wide enough to meet our detection bandwidth
232 criteria. */
233 /* This is actually centred at 2095Hz, but gets the balance we want, due
234 to the asymmetric walls of the notch */
235 famp = amp[i];
236 v1 = 0.76000f*famp - 0.1183852f*s->z1 - 0.5104039f*s->z2;
237 famp = v1 + 0.1567596f*s->z1 + s->z2;
238 s->z2 = s->z1;
239 s->z1 = v1;
240 notched = rintf(famp);
241 /* Estimate the overall energy in the channel, and the energy in
242 the notch (i.e. overall channel energy - tone energy => noise).
243 Use abs instead of multiply for speed (is it really faster?).
244 Damp the overall energy a little more for a stable result.
245 Damp the notch energy a little less, so we don't damp out the
246 blip every time the phase reverses */
247 s->channel_level += ((abs(amp[i]) - s->channel_level) >> 5);
248 s->notch_level += ((abs(notched) - s->notch_level) >> 4);
249 if (s->channel_level > 280)
250 {
251 /* There is adequate energy in the channel. Is it mostly at 2100Hz? */
252 if (s->notch_level*6 < s->channel_level)
253 {
254 /* The notch says yes, so we have the tone. */
255 if (!s->tone_present)
256 {
257 /* Do we get a kick every 450+-25ms? */
258 if (s->tone_cycle_duration >= ms_to_samples(425)
259 &&
260 s->tone_cycle_duration <= ms_to_samples(475))
261 {
262 if (++s->good_cycles > 2)
263 {
264 if (s->tone_callback)
265 s->tone_callback(s->callback_data, TRUE);
266 else
267 s->hit = TRUE;
268 }
269 }
270 s->tone_cycle_duration = 0;
271 s->tone_present = TRUE;
272 }
273 }
274 else
275 {
276 s->tone_present = FALSE;
277 }
278 s->tone_cycle_duration++;
279 }
280 else
281 {
282 s->tone_present = FALSE;
283 s->tone_cycle_duration = 0;
284 s->good_cycles = 0;
285 }
286 }
287 }
288 return 0;
289 }
290 /*- End of function --------------------------------------------------------*/
291
292 int modem_connect_tones_rx_get(modem_connect_tones_rx_state_t *s)
293 {
294 int x;
295
296 x = s->hit;
297 s->hit = FALSE;
298 return x;
299 }
300 /*- End of function --------------------------------------------------------*/
301
302 modem_connect_tones_rx_state_t *modem_connect_tones_rx_init(modem_connect_tones_rx_state_t *s,
303 int tone_type,
304 tone_report_func_t tone_callback,
305 void *user_data)
306 {
307 s->tone_type = tone_type;
308 s->channel_level = 0;
309 s->notch_level = 0;
310 s->tone_present = FALSE;
311 s->tone_cycle_duration = 0;
312 s->good_cycles = 0;
313 s->hit = FALSE;
314 s->tone_callback = tone_callback;
315 s->callback_data = user_data;
316 s->z1 = 0.0f;
317 s->z2 = 0.0f;
318 return s;
319 }
320 /*- End of function --------------------------------------------------------*/
321 /*- End of file ------------------------------------------------------------*/

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