00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * private/v27ter_rx.h - ITU V.27ter modem receive part 00005 * 00006 * Written by Steve Underwood <steveu@coppice.org> 00007 * 00008 * Copyright (C) 2003 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: v27ter_rx.h,v 1.1 2008/10/13 13:14:01 steveu Exp $ 00026 */ 00027 00028 #if !defined(_SPANDSP_PRIVATE_V27TER_RX_H_) 00029 #define _SPANDSP_PRIVATE_V27TER_RX_H_ 00030 00031 /*! 00032 V.27ter modem receive side descriptor. This defines the working state for a 00033 single instance of a V.27ter modem receiver. 00034 */ 00035 struct v27ter_rx_state_s 00036 { 00037 /*! \brief The bit rate of the modem. Valid values are 2400 and 4800. */ 00038 int bit_rate; 00039 /*! \brief The callback function used to put each bit received. */ 00040 put_bit_func_t put_bit; 00041 /*! \brief A user specified opaque pointer passed to the put_bit routine. */ 00042 void *put_bit_user_data; 00043 00044 /*! \brief The callback function used to report modem status changes. */ 00045 modem_rx_status_func_t status_handler; 00046 /*! \brief A user specified opaque pointer passed to the status function. */ 00047 void *status_user_data; 00048 00049 /*! \brief A callback function which may be enabled to report every symbol's 00050 constellation position. */ 00051 qam_report_handler_t qam_report; 00052 /*! \brief A user specified opaque pointer passed to the qam_report callback 00053 routine. */ 00054 void *qam_user_data; 00055 00056 /*! \brief The route raised cosine (RRC) pulse shaping filter buffer. */ 00057 #if defined(SPANDSP_USE_FIXED_POINT) 00058 int16_t rrc_filter[V27TER_RX_FILTER_STEPS]; 00059 #else 00060 float rrc_filter[V27TER_RX_FILTER_STEPS]; 00061 #endif 00062 /*! \brief Current offset into the RRC pulse shaping filter buffer. */ 00063 int rrc_filter_step; 00064 00065 /*! \brief The register for the training and data scrambler. */ 00066 unsigned int scramble_reg; 00067 /*! \brief A counter for the number of consecutive bits of repeating pattern through 00068 the scrambler. */ 00069 int scrambler_pattern_count; 00070 /*! \brief The current step in the table of BC constellation positions. */ 00071 int training_bc; 00072 /*! \brief TRUE if the previous trained values are to be reused. */ 00073 int old_train; 00074 /*! \brief The section of the training data we are currently in. */ 00075 int training_stage; 00076 /*! \brief A count of how far through the current training step we are. */ 00077 int training_count; 00078 /*! \brief A measure of how much mismatch there is between the real constellation, 00079 and the decoded symbol positions. */ 00080 float training_error; 00081 /*! \brief The value of the last signal sample, using the a simple HPF for signal power estimation. */ 00082 int16_t last_sample; 00083 /*! \brief >0 if a signal above the minimum is present. It may or may not be a V.27ter signal. */ 00084 int signal_present; 00085 /*! \brief Whether or not a carrier drop was detected and the signal delivery is pending. */ 00086 int carrier_drop_pending; 00087 /*! \brief A count of the current consecutive samples below the carrier off threshold. */ 00088 int low_samples; 00089 /*! \brief A highest magnitude sample seen. */ 00090 int16_t high_sample; 00091 00092 /*! \brief The position of the current symbol in the constellation, used for 00093 differential decoding. */ 00094 int constellation_state; 00095 00096 /*! \brief The current phase of the carrier (i.e. the DDS parameter). */ 00097 uint32_t carrier_phase; 00098 /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */ 00099 int32_t carrier_phase_rate; 00100 /*! \brief The carrier update rate saved for reuse when using short training. */ 00101 int32_t carrier_phase_rate_save; 00102 #if defined(SPANDSP_USE_FIXED_POINTx) 00103 /*! \brief The proportional part of the carrier tracking filter. */ 00104 float carrier_track_p; 00105 /*! \brief The integral part of the carrier tracking filter. */ 00106 float carrier_track_i; 00107 #else 00108 /*! \brief The proportional part of the carrier tracking filter. */ 00109 float carrier_track_p; 00110 /*! \brief The integral part of the carrier tracking filter. */ 00111 float carrier_track_i; 00112 #endif 00113 00114 /*! \brief A power meter, to measure the HPF'ed signal power in the channel. */ 00115 power_meter_t power; 00116 /*! \brief The power meter level at which carrier on is declared. */ 00117 int32_t carrier_on_power; 00118 /*! \brief The power meter level at which carrier off is declared. */ 00119 int32_t carrier_off_power; 00120 00121 /*! \brief Current read offset into the equalizer buffer. */ 00122 int eq_step; 00123 /*! \brief Current write offset into the equalizer buffer. */ 00124 int eq_put_step; 00125 /*! \brief Symbol counter to the next equalizer update. */ 00126 int eq_skip; 00127 00128 /*! \brief The current half of the baud. */ 00129 int baud_half; 00130 00131 #if defined(SPANDSP_USE_FIXED_POINT) 00132 /*! \brief The scaling factor accessed by the AGC algorithm. */ 00133 int16_t agc_scaling; 00134 /*! \brief The previous value of agc_scaling, needed to reuse old training. */ 00135 int16_t agc_scaling_save; 00136 00137 /*! \brief The current delta factor for updating the equalizer coefficients. */ 00138 float eq_delta; 00139 /*! \brief The adaptive equalizer coefficients. */ 00140 /*complexi16_t*/ complexf_t eq_coeff[V27TER_EQUALIZER_PRE_LEN + 1 + V27TER_EQUALIZER_POST_LEN]; 00141 /*! \brief A saved set of adaptive equalizer coefficients for use after restarts. */ 00142 /*complexi16_t*/ complexf_t eq_coeff_save[V27TER_EQUALIZER_PRE_LEN + 1 + V27TER_EQUALIZER_POST_LEN]; 00143 /*! \brief The equalizer signal buffer. */ 00144 /*complexi16_t*/ complexf_t eq_buf[V27TER_EQUALIZER_PRE_LEN + 1 + V27TER_EQUALIZER_POST_LEN]; 00145 #else 00146 /*! \brief The scaling factor accessed by the AGC algorithm. */ 00147 float agc_scaling; 00148 /*! \brief The previous value of agc_scaling, needed to reuse old training. */ 00149 float agc_scaling_save; 00150 00151 /*! \brief The current delta factor for updating the equalizer coefficients. */ 00152 float eq_delta; 00153 /*! \brief The adaptive equalizer coefficients. */ 00154 complexf_t eq_coeff[V27TER_EQUALIZER_PRE_LEN + 1 + V27TER_EQUALIZER_POST_LEN]; 00155 /*! \brief A saved set of adaptive equalizer coefficients for use after restarts. */ 00156 complexf_t eq_coeff_save[V27TER_EQUALIZER_PRE_LEN + 1 + V27TER_EQUALIZER_POST_LEN]; 00157 /*! \brief The equalizer signal buffer. */ 00158 complexf_t eq_buf[V27TER_EQUALIZER_PRE_LEN + 1 + V27TER_EQUALIZER_POST_LEN]; 00159 #endif 00160 00161 /*! \brief Integration variable for damping the Gardner algorithm tests. */ 00162 int gardner_integrate; 00163 /*! \brief Current step size of Gardner algorithm integration. */ 00164 int gardner_step; 00165 /*! \brief The total symbol timing correction since the carrier came up. 00166 This is only for performance analysis purposes. */ 00167 int total_baud_timing_correction; 00168 00169 /*! \brief Starting phase angles for the coarse carrier aquisition step. */ 00170 int32_t start_angles[2]; 00171 /*! \brief History list of phase angles for the coarse carrier aquisition step. */ 00172 int32_t angles[16]; 00173 /*! \brief Error and flow logging control */ 00174 logging_state_t logging; 00175 }; 00176 00177 #endif 00178 /*- End of file ------------------------------------------------------------*/