private/v22bis.h

00001 /*
00002  * SpanDSP - a series of DSP components for telephony
00003  *
00004  * private/v22bis.h - ITU V.22bis modem
00005  *
00006  * Written by Steve Underwood <steveu@coppice.org>
00007  *
00008  * Copyright (C) 2004 Steve Underwood
00009  *
00010  * All rights reserved.
00011  *
00012  * This program is free software; you can redistribute it and/or modify
00013  * it under the terms of the GNU Lesser General Public License version 2.1,
00014  * as published by the Free Software Foundation.
00015  *
00016  * This program is distributed in the hope that it will be useful,
00017  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  * GNU Lesser General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU Lesser General Public
00022  * License along with this program; if not, write to the Free Software
00023  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00024  *
00025  * $Id: v22bis.h,v 1.10 2009/04/29 12:37:45 steveu Exp $
00026  */
00027 
00028 #if !defined(_SPANDSP_PRIVATE_V22BIS_H_)
00029 #define _SPANDSP_PRIVATE_V22BIS_H_
00030 
00031 /*! Segments of the training sequence on the receive side */
00032 enum
00033 {
00034     V22BIS_RX_TRAINING_STAGE_NORMAL_OPERATION,
00035     V22BIS_RX_TRAINING_STAGE_SYMBOL_ACQUISITION,
00036     V22BIS_RX_TRAINING_STAGE_LOG_PHASE,
00037     V22BIS_RX_TRAINING_STAGE_UNSCRAMBLED_ONES,
00038     V22BIS_RX_TRAINING_STAGE_UNSCRAMBLED_ONES_SUSTAINING,
00039     V22BIS_RX_TRAINING_STAGE_SCRAMBLED_ONES_AT_1200,
00040     V22BIS_RX_TRAINING_STAGE_SCRAMBLED_ONES_AT_1200_SUSTAINING,
00041     V22BIS_RX_TRAINING_STAGE_WAIT_FOR_SCRAMBLED_ONES_AT_2400,
00042     V22BIS_RX_TRAINING_STAGE_PARKED
00043 };
00044 
00045 /*! Segments of the training sequence on the transmit side */
00046 enum
00047 {
00048     V22BIS_TX_TRAINING_STAGE_NORMAL_OPERATION = 0,
00049     V22BIS_TX_TRAINING_STAGE_INITIAL_TIMED_SILENCE,
00050     V22BIS_TX_TRAINING_STAGE_INITIAL_SILENCE,
00051     V22BIS_TX_TRAINING_STAGE_U11,
00052     V22BIS_TX_TRAINING_STAGE_U0011,
00053     V22BIS_TX_TRAINING_STAGE_S11,
00054     V22BIS_TX_TRAINING_STAGE_TIMED_S11,
00055     V22BIS_TX_TRAINING_STAGE_S1111,
00056     V22BIS_TX_TRAINING_STAGE_PARKED
00057 };
00058 
00059 /*!
00060     V.22bis modem descriptor. This defines the working state for a single instance
00061     of a V.22bis modem.
00062 */
00063 struct v22bis_state_s
00064 {
00065     /*! \brief The maximum permitted bit rate of the modem. Valid values are 1200 and 2400. */
00066     int bit_rate;
00067     /*! \brief TRUE is this is the calling side modem. */
00068     int caller;
00069     /*! \brief The callback function used to get the next bit to be transmitted. */
00070     get_bit_func_t get_bit;
00071     /*! \brief A user specified opaque pointer passed to the get_bit callback routine. */
00072     void *get_bit_user_data;
00073     /*! \brief The callback function used to put each bit received. */
00074     put_bit_func_t put_bit;
00075     /*! \brief A user specified opaque pointer passed to the put_bit callback routine. */
00076     void *put_bit_user_data;
00077     /*! \brief The callback function used to report modem status changes. */
00078     modem_rx_status_func_t status_handler;
00079     /*! \brief A user specified opaque pointer passed to the status function. */
00080     void *status_user_data;
00081 
00082     int negotiated_bit_rate;
00083 
00084     /* Receive section */
00085     struct
00086     {
00087         /*! \brief The route raised cosine (RRC) pulse shaping filter buffer. */
00088         float rrc_filter[2*V22BIS_RX_FILTER_STEPS];
00089         /*! \brief Current offset into the RRC pulse shaping filter buffer. */
00090         int rrc_filter_step;
00091 
00092         /*! \brief The register for the data scrambler. */
00093         unsigned int scramble_reg;
00094         /*! \brief A counter for the number of consecutive bits of repeating pattern through
00095                    the scrambler. */
00096         int scrambler_pattern_count;
00097 
00098         /*! \brief 0 if receiving user data. A training stage value during training */
00099         int training;
00100         /*! \brief A count of how far through the current training step we are. */
00101         int training_count;
00102 
00103         /*! \brief >0 if a signal above the minimum is present. It may or may not be a V.22bis signal. */
00104         int signal_present;
00105 
00106         /*! \brief A measure of how much mismatch there is between the real constellation,
00107             and the decoded symbol positions. */
00108         float training_error;
00109 
00110         /*! \brief The current phase of the carrier (i.e. the DDS parameter). */
00111         uint32_t carrier_phase;
00112         /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
00113         int32_t carrier_phase_rate;
00114         /*! \brief The proportional part of the carrier tracking filter. */
00115         float carrier_track_p;
00116         /*! \brief The integral part of the carrier tracking filter. */
00117         float carrier_track_i;
00118         
00119         /*! \brief A callback function which may be enabled to report every symbol's
00120                    constellation position. */
00121         qam_report_handler_t qam_report;
00122         /*! \brief A user specified opaque pointer passed to the qam_report callback
00123                    routine. */
00124         void *qam_user_data;
00125 
00126         /*! \brief A power meter, to measure the HPF'ed signal power in the channel. */    
00127         power_meter_t rx_power;
00128         /*! \brief The power meter level at which carrier on is declared. */
00129         int32_t carrier_on_power;
00130         /*! \brief The power meter level at which carrier off is declared. */
00131         int32_t carrier_off_power;
00132         /*! \brief The scaling factor accessed by the AGC algorithm. */
00133         float agc_scaling;
00134     
00135         int constellation_state;
00136 
00137         /*! \brief The current delta factor for updating the equalizer coefficients. */
00138         float eq_delta;
00139 #if defined(SPANDSP_USE_FIXED_POINTx)
00140         /*! \brief The adaptive equalizer coefficients. */
00141         complexi_t eq_coeff[2*V22BIS_EQUALIZER_LEN + 1];
00142         /*! \brief The equalizer signal buffer. */
00143         complexi_t eq_buf[V22BIS_EQUALIZER_MASK + 1];
00144 #else
00145         complexf_t eq_coeff[2*V22BIS_EQUALIZER_LEN + 1];
00146         complexf_t eq_buf[V22BIS_EQUALIZER_MASK + 1];
00147 #endif
00148         /*! \brief Current offset into the equalizer buffer. */
00149         int eq_step;
00150         /*! \brief Current write offset into the equalizer buffer. */
00151         int eq_put_step;
00152 
00153         /*! \brief Integration variable for damping the Gardner algorithm tests. */
00154         int gardner_integrate;
00155         /*! \brief Current step size of Gardner algorithm integration. */
00156         int gardner_step;
00157         /*! \brief The total symbol timing correction since the carrier came up.
00158                    This is only for performance analysis purposes. */
00159         int total_baud_timing_correction;
00160         /*! \brief The current fractional phase of the baud timing. */
00161         int baud_phase;
00162     
00163         int sixteen_way_decisions;
00164 
00165         int pattern_repeats;
00166         int last_raw_bits;
00167     } rx;
00168 
00169     /* Transmit section */
00170     struct
00171     {
00172         /*! \brief The gain factor needed to achieve the specified output power. */
00173         float gain;
00174 
00175         /*! \brief The route raised cosine (RRC) pulse shaping filter buffer. */
00176         complexf_t rrc_filter[2*V22BIS_TX_FILTER_STEPS];
00177         /*! \brief Current offset into the RRC pulse shaping filter buffer. */
00178         int rrc_filter_step;
00179 
00180         /*! \brief The register for the data scrambler. */
00181         unsigned int scramble_reg;
00182         /*! \brief A counter for the number of consecutive bits of repeating pattern through
00183                    the scrambler. */
00184         int scrambler_pattern_count;
00185 
00186         /*! \brief 0 if transmitting user data. A training stage value during training */
00187         int training;
00188         /*! \brief A counter used to track progress through sending the training sequence. */
00189         int training_count;
00190         /*! \brief The current phase of the carrier (i.e. the DDS parameter). */
00191         uint32_t carrier_phase;
00192         /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
00193         int32_t carrier_phase_rate;
00194         /*! \brief The current phase of the guard tone (i.e. the DDS parameter). */
00195         uint32_t guard_phase;
00196         /*! \brief The update rate for the phase of the guard tone (i.e. the DDS increment). */
00197         int32_t guard_phase_rate;
00198         float guard_level;
00199         /*! \brief The current fractional phase of the baud timing. */
00200         int baud_phase;
00201         /*! \brief The code number for the current position in the constellation. */
00202         int constellation_state;
00203         /*! \brief An indicator to mark that we are tidying up to stop transmission. */
00204         int shutdown;
00205         /*! \brief The get_bit function in use at any instant. */
00206         get_bit_func_t current_get_bit;
00207     } tx;
00208 
00209     /*! \brief Error and flow logging control */
00210     logging_state_t logging;
00211 };
00212 
00213 #if defined(__cplusplus)
00214 extern "C"
00215 {
00216 #endif
00217 
00218 /*! Reinitialise an existing V.22bis modem receive context.
00219     \brief Reinitialise an existing V.22bis modem receive context.
00220     \param s The modem context.
00221     \return 0 for OK, -1 for bad parameter */
00222 int v22bis_rx_restart(v22bis_state_t *s);
00223 
00224 void v22bis_report_status_change(v22bis_state_t *s, int status);
00225 
00226 void v22bis_equalizer_coefficient_reset(v22bis_state_t *s);
00227 
00228 #if defined(__cplusplus)
00229 }
00230 #endif
00231 
00232 #endif
00233 /*- End of file ------------------------------------------------------------*/

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