Mercurial > hg > audiostuff
view spandsp-0.0.3/spandsp-0.0.3/src/modem_connect_tones.c @ 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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/* * SpanDSP - a series of DSP components for telephony * * modem_connect_tones.c - Generation and detection of tones * associated with modems calling and answering calls. * * Written by Steve Underwood <steveu@coppice.org> * * Copyright (C) 2006 Steve Underwood * * All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2, as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * * $Id: modem_connect_tones.c,v 1.6 2006/11/30 15:41:47 steveu Exp $ */ /*! \file */ #ifdef HAVE_CONFIG_H #include <config.h> #endif #include <inttypes.h> #include <stdlib.h> #if defined(HAVE_TGMATH_H) #include <tgmath.h> #endif #if defined(HAVE_MATH_H) #include <math.h> #endif #include "spandsp/telephony.h" #include "spandsp/dds.h" #include "spandsp/tone_detect.h" #include "spandsp/tone_generate.h" #include "spandsp/super_tone_rx.h" #include "spandsp/modem_connect_tones.h" int modem_connect_tones_tx(modem_connect_tones_tx_state_t *s, int16_t amp[], int len) { int mod; int i; switch (s->tone_type) { case MODEM_CONNECT_TONES_FAX_CNG: case MODEM_CONNECT_TONES_FAX_CED: len = tone_gen(&s->tone_tx, amp, len); break; case MODEM_CONNECT_TONES_EC_DISABLE: for (i = 0; i < len; i++) { if (--s->hop_timer <= 0) { s->hop_timer = ms_to_samples(450); s->tone_phase += 0x80000000; } amp[i] = dds_mod(&s->tone_phase, s->tone_phase_rate, s->level, 0); } break; case MODEM_CONNECT_TONES_EC_DISABLE_MOD: for (i = 0; i < len; i++) { mod = s->level + dds_mod(&s->mod_phase, s->mod_phase_rate, s->mod_level, 0); if (--s->hop_timer <= 0) { s->hop_timer = ms_to_samples(450); s->tone_phase += 0x80000000; } amp[i] = dds_mod(&s->tone_phase, s->tone_phase_rate, mod, 0); } break; } return len; } /*- End of function --------------------------------------------------------*/ modem_connect_tones_tx_state_t *modem_connect_tones_tx_init(modem_connect_tones_tx_state_t *s, int tone_type) { tone_gen_descriptor_t tone_desc; s->tone_type = tone_type; switch (s->tone_type) { case MODEM_CONNECT_TONES_FAX_CNG: make_tone_gen_descriptor(&tone_desc, 1100, -11, 0, 0, 500, 3000, 0, 0, TRUE); tone_gen_init(&s->tone_tx, &tone_desc); break; case MODEM_CONNECT_TONES_FAX_CED: make_tone_gen_descriptor(&tone_desc, 2100, -11, 0, 0, 2600, 0, 0, 0, FALSE); tone_gen_init(&s->tone_tx, &tone_desc); break; case MODEM_CONNECT_TONES_EC_DISABLE: case MODEM_CONNECT_TONES_EC_DISABLE_MOD: s->tone_phase_rate = dds_phase_rate(2100.0); s->mod_phase_rate = dds_phase_rate(15.0); s->tone_phase = 0; s->mod_phase = 0; s->hop_timer = ms_to_samples(450); s->level = dds_scaling_dbm0(-12); if (s->tone_type == MODEM_CONNECT_TONES_EC_DISABLE_MOD) s->mod_level = s->level/5; else s->mod_level = 0; } return s; } /*- End of function --------------------------------------------------------*/ int modem_connect_tones_rx(modem_connect_tones_rx_state_t *s, const int16_t amp[], int len) { int i; int16_t notched; float v1; float famp; switch (s->tone_type) { case MODEM_CONNECT_TONES_FAX_CNG: for (i = 0; i < len; i++) { /* A Cauer notch at 1100Hz, spread just wide enough to meet our detection bandwidth criteria. */ famp = amp[i]; v1 = 0.792928f*famp + 1.0018744927985f*s->z1 - 0.54196833412465f*s->z2; famp = v1 - 1.2994747954630f*s->z1 + s->z2; s->z2 = s->z1; s->z1 = v1; notched = rintf(famp); /* Estimate the overall energy in the channel, and the energy in the notch (i.e. overall channel energy - tone energy => noise). Use abs instead of multiply for speed (is it really faster?). */ s->channel_level += ((abs(amp[i]) - s->channel_level) >> 5); s->notch_level += ((abs(notched) - s->notch_level) >> 5); if (s->channel_level > 70 && s->notch_level*6 < s->channel_level) { /* There is adequate energy in the channel, and it is mostly at 1100Hz. */ if (!s->tone_present) { if (++s->tone_cycle_duration >= ms_to_samples(415)) { if (s->tone_callback) s->tone_callback(s->callback_data, TRUE); else s->hit = TRUE; s->tone_present = TRUE; } } } else { s->tone_cycle_duration = 0; } } break; case MODEM_CONNECT_TONES_FAX_CED: for (i = 0; i < len; i++) { /* A Cauer notch at 2100Hz, spread just wide enough to meet our detection bandwidth criteria. */ famp = amp[i]; v1 = 0.76000f*famp - 0.1183852f*s->z1 - 0.5104039f*s->z2; famp = v1 + 0.1567596f*s->z1 + s->z2; s->z2 = s->z1; s->z1 = v1; notched = rintf(famp); /* Estimate the overall energy in the channel, and the energy in the notch (i.e. overall channel energy - tone energy => noise). Use abs instead of multiply for speed (is it really faster?). */ s->channel_level += ((abs(amp[i]) - s->channel_level) >> 5); s->notch_level += ((abs(notched) - s->notch_level) >> 5); if (s->channel_level > 70 && s->notch_level*6 < s->channel_level) { /* There is adequate energy in the channel, and it is mostly at 2100Hz. */ if (!s->tone_present) { if (++s->tone_cycle_duration >= ms_to_samples(500)) { if (s->tone_callback) s->tone_callback(s->callback_data, TRUE); else s->hit = TRUE; s->tone_present = TRUE; } } } else { s->tone_cycle_duration = 0; } } break; case MODEM_CONNECT_TONES_EC_DISABLE: case MODEM_CONNECT_TONES_EC_DISABLE_MOD: for (i = 0; i < len; i++) { /* A Cauer notch at 2100Hz, spread just wide enough to meet our detection bandwidth criteria. */ /* This is actually centred at 2095Hz, but gets the balance we want, due to the asymmetric walls of the notch */ famp = amp[i]; v1 = 0.76000f*famp - 0.1183852f*s->z1 - 0.5104039f*s->z2; famp = v1 + 0.1567596f*s->z1 + s->z2; s->z2 = s->z1; s->z1 = v1; notched = rintf(famp); /* Estimate the overall energy in the channel, and the energy in the notch (i.e. overall channel energy - tone energy => noise). Use abs instead of multiply for speed (is it really faster?). Damp the overall energy a little more for a stable result. Damp the notch energy a little less, so we don't damp out the blip every time the phase reverses */ s->channel_level += ((abs(amp[i]) - s->channel_level) >> 5); s->notch_level += ((abs(notched) - s->notch_level) >> 4); if (s->channel_level > 280) { /* There is adequate energy in the channel. Is it mostly at 2100Hz? */ if (s->notch_level*6 < s->channel_level) { /* The notch says yes, so we have the tone. */ if (!s->tone_present) { /* Do we get a kick every 450+-25ms? */ if (s->tone_cycle_duration >= ms_to_samples(425) && s->tone_cycle_duration <= ms_to_samples(475)) { if (++s->good_cycles > 2) { if (s->tone_callback) s->tone_callback(s->callback_data, TRUE); else s->hit = TRUE; } } s->tone_cycle_duration = 0; s->tone_present = TRUE; } } else { s->tone_present = FALSE; } s->tone_cycle_duration++; } else { s->tone_present = FALSE; s->tone_cycle_duration = 0; s->good_cycles = 0; } } } return 0; } /*- End of function --------------------------------------------------------*/ int modem_connect_tones_rx_get(modem_connect_tones_rx_state_t *s) { int x; x = s->hit; s->hit = FALSE; return x; } /*- End of function --------------------------------------------------------*/ modem_connect_tones_rx_state_t *modem_connect_tones_rx_init(modem_connect_tones_rx_state_t *s, int tone_type, tone_report_func_t tone_callback, void *user_data) { s->tone_type = tone_type; s->channel_level = 0; s->notch_level = 0; s->tone_present = FALSE; s->tone_cycle_duration = 0; s->good_cycles = 0; s->hit = FALSE; s->tone_callback = tone_callback; s->callback_data = user_data; s->z1 = 0.0f; s->z2 = 0.0f; return s; } /*- End of function --------------------------------------------------------*/ /*- End of file ------------------------------------------------------------*/