spandsp 0.0.6
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00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * private/sig_tone.h - Signalling tone processing for the 2280Hz, 2400Hz, 2600Hz 00005 * and similar signalling tones used in older protocols. 00006 * 00007 * Written by Steve Underwood <steveu@coppice.org> 00008 * 00009 * Copyright (C) 2004 Steve Underwood 00010 * 00011 * All rights reserved. 00012 * 00013 * This program is free software; you can redistribute it and/or modify 00014 * it under the terms of the GNU Lesser General Public License version 2.1, 00015 * as published by the Free Software Foundation. 00016 * 00017 * This program is distributed in the hope that it will be useful, 00018 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00019 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00020 * GNU Lesser General Public License for more details. 00021 * 00022 * You should have received a copy of the GNU Lesser General Public 00023 * License along with this program; if not, write to the Free Software 00024 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 00025 */ 00026 00027 #if !defined(_SPANDSP_PRIVATE_SIG_TONE_H_) 00028 #define _SPANDSP_PRIVATE_SIG_TONE_H_ 00029 00030 /*! \brief The coefficient set for a pair of cascaded bi-quads that make a signalling notch filter. */ 00031 typedef struct 00032 { 00033 #if defined(SPANDSP_USE_FIXED_POINT) 00034 int16_t a1[3]; 00035 int16_t b1[3]; 00036 int16_t a2[3]; 00037 int16_t b2[3]; 00038 int postscale; 00039 #else 00040 float a1[3]; 00041 float b1[3]; 00042 float a2[3]; 00043 float b2[3]; 00044 #endif 00045 } sig_tone_notch_coeffs_t; 00046 00047 /*! \brief The coefficient set for a bi-quad that makes a signalling flat filter. 00048 Some signalling tone schemes require such a filter, and some don't. 00049 It is termed a flat filter, to distinguish it from the sharp filter, 00050 but obviously it is not actually flat. It is a broad band weighting 00051 filter. */ 00052 typedef struct 00053 { 00054 #if defined(SPANDSP_USE_FIXED_POINT) 00055 /*! \brief Flat mode bandpass bi-quad parameters */ 00056 int16_t a[3]; 00057 /*! \brief Flat mode bandpass bi-quad parameters */ 00058 int16_t b[3]; 00059 /*! \brief Post filter scaling */ 00060 int postscale; 00061 #else 00062 /*! \brief Flat mode bandpass bi-quad parameters */ 00063 float a[3]; 00064 /*! \brief Flat mode bandpass bi-quad parameters */ 00065 float b[3]; 00066 #endif 00067 } sig_tone_flat_coeffs_t; 00068 00069 /*! 00070 signalling tone descriptor. This defines the working state for a 00071 single instance of the transmit and receive sides of a signalling 00072 tone processor. 00073 */ 00074 typedef struct 00075 { 00076 /*! \brief The tones used. */ 00077 int tone_freq[2]; 00078 /*! \brief The high and low tone amplitudes for each of the tones, in dBm0. */ 00079 int tone_amp[2][2]; 00080 00081 /*! \brief The delay, in audio samples, before the high level tone drops 00082 to a low level tone. Some signalling protocols require the 00083 signalling tone be started at a high level, to ensure crisp 00084 initial detection at the receiver, but require the tone 00085 amplitude to drop by a number of dBs if it is sustained, 00086 to reduce crosstalk levels. */ 00087 int high_low_timeout; 00088 00089 /*! \brief Some signalling tone detectors use a sharp initial filter, 00090 changing to a broader, flatter, filter after some delay. This 00091 parameter defines the delay. 0 means it never changes. */ 00092 int sharp_flat_timeout; 00093 00094 /*! \brief Parameters to control the behaviour of the notch filter, used 00095 to remove the tone from the voice path in some protocols. The 00096 notch is applied as fast as possible, when the signalling tone 00097 is detected. Its removal is delayed by this timeout, to avoid 00098 clicky noises from repeated switching of the filter on rapid 00099 pulses of signalling tone. */ 00100 int notch_lag_time; 00101 00102 /*! \brief The tone on persistence check, in audio samples. */ 00103 int tone_on_check_time; 00104 /*! \brief The tone off persistence check, in audio samples. */ 00105 int tone_off_check_time; 00106 00107 /*! \brief The number of tones used. */ 00108 int tones; 00109 /*! \brief The coefficients for the cascaded bi-quads notch filter. */ 00110 const sig_tone_notch_coeffs_t *notch[2]; 00111 /*! \brief The coefficients for the single bi-quad flat mode filter. */ 00112 const sig_tone_flat_coeffs_t *flat; 00113 00114 /*! \brief Minimum signalling tone to total power ratio, in dB */ 00115 int16_t detection_ratio; 00116 /*! \brief Minimum total power for detection in sharp mode, in dB */ 00117 int16_t sharp_detection_threshold; 00118 /*! \brief Minimum total power for detection in flat mode, in dB */ 00119 int16_t flat_detection_threshold; 00120 } sig_tone_descriptor_t; 00121 00122 /*! 00123 Signalling tone transmit state 00124 */ 00125 struct sig_tone_tx_state_s 00126 { 00127 /*! \brief The callback function used to handle signalling changes. */ 00128 tone_report_func_t sig_update; 00129 /*! \brief A user specified opaque pointer passed to the callback function. */ 00130 void *user_data; 00131 00132 /*! \brief Tone descriptor */ 00133 const sig_tone_descriptor_t *desc; 00134 00135 /*! The phase rates for the one or two tones */ 00136 int32_t phase_rate[2]; 00137 /*! The phase accumulators for the one or two tones */ 00138 uint32_t phase_acc[2]; 00139 00140 /*! The scaling values for the one or two tones, and the high and low level of each tone */ 00141 int16_t tone_scaling[2][2]; 00142 /*! The sample timer, used to switch between the high and low level tones. */ 00143 int high_low_timer; 00144 00145 /*! \brief Current transmit tone */ 00146 int current_tx_tone; 00147 /*! \brief Current transmit timeout */ 00148 int current_tx_timeout; 00149 /*! \brief Time in current signalling state, in samples. */ 00150 int signalling_state_duration; 00151 }; 00152 00153 /*! 00154 Signalling tone receive state 00155 */ 00156 struct sig_tone_rx_state_s 00157 { 00158 /*! \brief The callback function used to handle signalling changes. */ 00159 tone_report_func_t sig_update; 00160 /*! \brief A user specified opaque pointer passed to the callback function. */ 00161 void *user_data; 00162 00163 /*! \brief Tone descriptor */ 00164 const sig_tone_descriptor_t *desc; 00165 00166 /*! \brief The current receive tone */ 00167 int current_rx_tone; 00168 /*! \brief The timeout for switching from the high level to low level tone detector. */ 00169 int high_low_timer; 00170 /*! \brief ??? */ 00171 int current_notch_filter; 00172 00173 struct 00174 { 00175 #if defined(SPANDSP_USE_FIXED_POINT) 00176 /*! \brief The z's for the notch filter */ 00177 int16_t notch_z1[2]; 00178 /*! \brief The z's for the notch filter */ 00179 int16_t notch_z2[2]; 00180 #else 00181 /*! \brief The z's for the notch filter */ 00182 float notch_z1[2]; 00183 /*! \brief The z's for the notch filter */ 00184 float notch_z2[2]; 00185 #endif 00186 00187 /*! \brief The power output of the notch. */ 00188 power_meter_t power; 00189 } tone[3]; 00190 00191 #if defined(SPANDSP_USE_FIXED_POINT) 00192 /*! \brief The z's for the weighting/bandpass filter. */ 00193 int16_t flat_z[2]; 00194 #else 00195 /*! \brief The z's for the weighting/bandpass filter. */ 00196 float flat_z[2]; 00197 #endif 00198 /*! \brief The output power of the flat (unfiltered or flat filtered) path. */ 00199 power_meter_t flat_power; 00200 00201 /*! \brief Persistence check for tone present */ 00202 int tone_persistence_timeout; 00203 /*! \brief The tone pattern on the last audio sample */ 00204 int last_sample_tone_present; 00205 00206 /*! \brief The minimum reading from the power meter for detection in flat mode */ 00207 int32_t flat_detection_threshold; 00208 /*! \brief The minimum reading from the power meter for detection in sharp mode */ 00209 int32_t sharp_detection_threshold; 00210 /*! \brief The minimum ratio between notched power and total power for detection */ 00211 int32_t detection_ratio; 00212 00213 /*! \brief TRUE if in flat mode. FALSE if in sharp mode. */ 00214 int flat_mode; 00215 /*! \brief TRUE if the notch filter is enabled in the media path */ 00216 int notch_enabled; 00217 /*! \brief ??? */ 00218 int flat_mode_timeout; 00219 /*! \brief ??? */ 00220 int notch_insertion_timeout; 00221 00222 /*! \brief ??? */ 00223 int signalling_state; 00224 /*! \brief ??? */ 00225 int signalling_state_duration; 00226 }; 00227 00228 #endif 00229 /*- End of file ------------------------------------------------------------*/