1 /* 2 * SpanDSP - a series of DSP components for telephony 3 * 4 * private/v22bis.h - ITU V.22bis modem 5 * 6 * Written by Steve Underwood <steveu@coppice.org> 7 * 8 * Copyright (C) 2004 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 Lesser General Public License version 2.1, 14 * as 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 Lesser General Public License for more details. 20 * 21 * You should have received a copy of the GNU Lesser General Public 22 * License along with this program; if not, write to the Free Software 23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 24 */ 25 26 #if !defined(_SPANDSP_PRIVATE_V22BIS_H_) 27 #define _SPANDSP_PRIVATE_V22BIS_H_ 28 29 /*! The length of the equalizer buffer */ 30 #define V22BIS_EQUALIZER_LEN 17 31 /*! Samples before the target position in the equalizer buffer */ 32 #define V22BIS_EQUALIZER_PRE_LEN 8 33 34 /*! The number of taps in the transmit pulse shaping filter */ 35 #define V22BIS_TX_FILTER_STEPS 9 36 37 /*! The number of taps in the receive pulse shaping/bandpass filter */ 38 #define V22BIS_RX_FILTER_STEPS 27 39 40 /*! Segments of the training sequence on the receive side */ 41 enum 42 { 43 V22BIS_RX_TRAINING_STAGE_NORMAL_OPERATION, 44 V22BIS_RX_TRAINING_STAGE_SYMBOL_ACQUISITION, 45 V22BIS_RX_TRAINING_STAGE_LOG_PHASE, 46 V22BIS_RX_TRAINING_STAGE_UNSCRAMBLED_ONES, 47 V22BIS_RX_TRAINING_STAGE_UNSCRAMBLED_ONES_SUSTAINING, 48 V22BIS_RX_TRAINING_STAGE_SCRAMBLED_ONES_AT_1200, 49 V22BIS_RX_TRAINING_STAGE_SCRAMBLED_ONES_AT_1200_SUSTAINING, 50 V22BIS_RX_TRAINING_STAGE_WAIT_FOR_SCRAMBLED_ONES_AT_2400, 51 V22BIS_RX_TRAINING_STAGE_PARKED 52 }; 53 54 /*! Segments of the training sequence on the transmit side */ 55 enum 56 { 57 V22BIS_TX_TRAINING_STAGE_NORMAL_OPERATION = 0, 58 V22BIS_TX_TRAINING_STAGE_INITIAL_TIMED_SILENCE, 59 V22BIS_TX_TRAINING_STAGE_INITIAL_SILENCE, 60 V22BIS_TX_TRAINING_STAGE_U11, 61 V22BIS_TX_TRAINING_STAGE_U0011, 62 V22BIS_TX_TRAINING_STAGE_S11, 63 V22BIS_TX_TRAINING_STAGE_TIMED_S11, 64 V22BIS_TX_TRAINING_STAGE_S1111, 65 V22BIS_TX_TRAINING_STAGE_PARKED 66 }; 67 68 #if defined(SPANDSP_USE_FIXED_POINT) 69 extern const complexi16_t v22bis_constellation[16]; 70 #else 71 extern const complexf_t v22bis_constellation[16]; 72 #endif 73 74 /*! 75 V.22bis modem descriptor. This defines the working state for a single instance 76 of a V.22bis modem. 77 */ 78 struct v22bis_state_s 79 { 80 /*! \brief The maximum permitted bit rate of the modem. Valid values are 1200 and 2400. */ 81 int bit_rate; 82 /*! \brief True is this is the calling side modem. */ 83 bool calling_party; 84 /*! \brief The callback function used to get the next bit to be transmitted. */ 85 get_bit_func_t get_bit; 86 /*! \brief A user specified opaque pointer passed to the get_bit callback routine. */ 87 void *get_bit_user_data; 88 /*! \brief The callback function used to put each bit received. */ 89 put_bit_func_t put_bit; 90 /*! \brief A user specified opaque pointer passed to the put_bit callback routine. */ 91 void *put_bit_user_data; 92 /*! \brief The callback function used to report modem status changes. */ 93 modem_status_func_t status_handler; 94 /*! \brief A user specified opaque pointer passed to the status function. */ 95 void *status_user_data; 96 97 int negotiated_bit_rate; 98 99 /* Receive section */ 100 struct 101 { 102 /*! \brief Current offset into the RRC pulse shaping filter buffer. */ 103 int rrc_filter_step; 104 105 /*! \brief The register for the data scrambler. */ 106 uint32_t scramble_reg; 107 /*! \brief A counter for the number of consecutive bits of repeating pattern through 108 the scrambler. */ 109 int scrambler_pattern_count; 110 111 /*! \brief 0 if receiving user data. A training stage value during training */ 112 int training; 113 /*! \brief A count of how far through the current training step we are. */ 114 int training_count; 115 116 /*! \brief >0 if a signal above the minimum is present. It may or may not be a V.22bis signal. */ 117 int signal_present; 118 119 /*! \brief The current phase of the carrier (i.e. the DDS parameter). */ 120 uint32_t carrier_phase; 121 /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */ 122 int32_t carrier_phase_rate; 123 124 /*! \brief A callback function which may be enabled to report every symbol's 125 constellation position. */ 126 qam_report_handler_t qam_report; 127 /*! \brief A user specified opaque pointer passed to the qam_report callback 128 routine. */ 129 void *qam_user_data; 130 131 /*! \brief A power meter, to measure the HPF'ed signal power in the channel. */ 132 power_meter_t rx_power; 133 /*! \brief The power meter level at which carrier on is declared. */ 134 int32_t carrier_on_power; 135 /*! \brief The power meter level at which carrier off is declared. */ 136 int32_t carrier_off_power; 137 138 int constellation_state; 139 140 #if defined(SPANDSP_USE_FIXED_POINT) 141 /*! \brief The scaling factor assessed by the AGC algorithm. */ 142 int16_t agc_scaling; 143 /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */ 144 int16_t rrc_filter[V22BIS_RX_FILTER_STEPS]; 145 146 /*! \brief The current delta factor for updating the equalizer coefficients. */ 147 int16_t eq_delta; 148 /*! \brief The adaptive equalizer coefficients. */ 149 complexi16_t eq_coeff[V22BIS_EQUALIZER_LEN]; 150 /*! \brief The equalizer signal buffer. */ 151 complexi16_t eq_buf[V22BIS_EQUALIZER_LEN]; 152 153 /*! \brief A measure of how much mismatch there is between the real constellation, 154 and the decoded symbol positions. */ 155 int32_t training_error; 156 /*! \brief The proportional part of the carrier tracking filter. */ 157 int32_t carrier_track_p; 158 /*! \brief The integral part of the carrier tracking filter. */ 159 int32_t carrier_track_i; 160 #else 161 /*! \brief The scaling factor assessed by the AGC algorithm. */ 162 float agc_scaling; 163 /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */ 164 float rrc_filter[V22BIS_RX_FILTER_STEPS]; 165 166 /*! \brief The current delta factor for updating the equalizer coefficients. */ 167 float eq_delta; 168 /*! \brief The adaptive equalizer coefficients. */ 169 complexf_t eq_coeff[V22BIS_EQUALIZER_LEN]; 170 /*! \brief The equalizer signal buffer. */ 171 complexf_t eq_buf[V22BIS_EQUALIZER_LEN]; 172 173 /*! \brief A measure of how much mismatch there is between the real constellation, 174 and the decoded symbol positions. */ 175 float training_error; 176 /*! \brief The proportional part of the carrier tracking filter. */ 177 float carrier_track_p; 178 /*! \brief The integral part of the carrier tracking filter. */ 179 float carrier_track_i; 180 #endif 181 /*! \brief Current offset into the equalizer buffer. */ 182 int eq_step; 183 /*! \brief Current write offset into the equalizer buffer. */ 184 int eq_put_step; 185 186 /*! \brief Integration variable for damping the Gardner algorithm tests. */ 187 int gardner_integrate; 188 /*! \brief Current step size of Gardner algorithm integration. */ 189 int gardner_step; 190 /*! \brief The total symbol timing correction since the carrier came up. 191 This is only for performance analysis purposes. */ 192 int total_baud_timing_correction; 193 /*! \brief The current fractional phase of the baud timing. */ 194 int baud_phase; 195 196 int sixteen_way_decisions; 197 198 int pattern_repeats; 199 int last_raw_bits; 200 } rx; 201 202 /* Transmit section */ 203 struct 204 { 205 #if defined(SPANDSP_USE_FIXED_POINT) 206 /*! \brief The guard tone level. */ 207 int16_t guard_tone_gain; 208 /*! \brief The gain factor needed to achieve the specified output power. */ 209 int16_t gain; 210 /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */ 211 int16_t rrc_filter_re[V22BIS_TX_FILTER_STEPS]; 212 int16_t rrc_filter_im[V22BIS_TX_FILTER_STEPS]; 213 #else 214 /*! \brief The guard tone level. */ 215 float guard_tone_gain; 216 /*! \brief The gain factor needed to achieve the specified output power. */ 217 float gain; 218 /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */ 219 float rrc_filter_re[V22BIS_TX_FILTER_STEPS]; 220 float rrc_filter_im[V22BIS_TX_FILTER_STEPS]; 221 #endif 222 223 /*! \brief Current offset into the RRC pulse shaping filter buffer. */ 224 int rrc_filter_step; 225 226 /*! \brief The register for the data scrambler. */ 227 uint32_t scramble_reg; 228 /*! \brief A counter for the number of consecutive bits of repeating pattern through 229 the scrambler. */ 230 int scrambler_pattern_count; 231 232 /*! \brief 0 if transmitting user data. A training stage value during training */ 233 int training; 234 /*! \brief A counter used to track progress through sending the training sequence. */ 235 int training_count; 236 /*! \brief The current phase of the carrier (i.e. the DDS parameter). */ 237 uint32_t carrier_phase; 238 /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */ 239 int32_t carrier_phase_rate; 240 /*! \brief The current phase of the guard tone (i.e. the DDS parameter). */ 241 uint32_t guard_phase; 242 /*! \brief The update rate for the phase of the guard tone (i.e. the DDS increment). */ 243 int32_t guard_phase_rate; 244 /*! \brief The current fractional phase of the baud timing. */ 245 int baud_phase; 246 /*! \brief The code number for the current position in the constellation. */ 247 int constellation_state; 248 /*! \brief An indicator to mark that we are tidying up to stop transmission. */ 249 int shutdown; 250 /*! \brief The get_bit function in use at any instant. */ 251 get_bit_func_t current_get_bit; 252 } tx; 253 254 /*! \brief Error and flow logging control */ 255 logging_state_t logging; 256 }; 257 258 #if defined(__cplusplus) 259 extern "C" 260 { 261 #endif 262 263 /*! Reinitialise an existing V.22bis modem receive context. 264 \brief Reinitialise an existing V.22bis modem receive context. 265 \param s The modem context. 266 \return 0 for OK, -1 for bad parameter */ 267 int v22bis_rx_restart(v22bis_state_t *s); 268 269 void v22bis_report_status_change(v22bis_state_t *s, int status); 270 271 void v22bis_equalizer_coefficient_reset(v22bis_state_t *s); 272 273 #if defined(__cplusplus) 274 } 275 #endif 276 277 #endif 278 /*- End of file ------------------------------------------------------------*/ 279