279 lines
11 KiB
C
279 lines
11 KiB
C
/*
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* SpanDSP - a series of DSP components for telephony
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*
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* private/v22bis.h - ITU V.22bis modem
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*
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* Written by Steve Underwood <steveu@coppice.org>
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*
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* Copyright (C) 2004 Steve Underwood
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License version 2.1,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#if !defined(_SPANDSP_PRIVATE_V22BIS_H_)
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#define _SPANDSP_PRIVATE_V22BIS_H_
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/*! The length of the equalizer buffer */
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#define V22BIS_EQUALIZER_LEN 17
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/*! Samples before the target position in the equalizer buffer */
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#define V22BIS_EQUALIZER_PRE_LEN 8
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/*! The number of taps in the transmit pulse shaping filter */
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#define V22BIS_TX_FILTER_STEPS 9
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/*! The number of taps in the receive pulse shaping/bandpass filter */
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#define V22BIS_RX_FILTER_STEPS 27
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/*! Segments of the training sequence on the receive side */
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enum
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{
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V22BIS_RX_TRAINING_STAGE_NORMAL_OPERATION,
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V22BIS_RX_TRAINING_STAGE_SYMBOL_ACQUISITION,
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V22BIS_RX_TRAINING_STAGE_LOG_PHASE,
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V22BIS_RX_TRAINING_STAGE_UNSCRAMBLED_ONES,
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V22BIS_RX_TRAINING_STAGE_UNSCRAMBLED_ONES_SUSTAINING,
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V22BIS_RX_TRAINING_STAGE_SCRAMBLED_ONES_AT_1200,
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V22BIS_RX_TRAINING_STAGE_SCRAMBLED_ONES_AT_1200_SUSTAINING,
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V22BIS_RX_TRAINING_STAGE_WAIT_FOR_SCRAMBLED_ONES_AT_2400,
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V22BIS_RX_TRAINING_STAGE_PARKED
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};
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/*! Segments of the training sequence on the transmit side */
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enum
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{
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V22BIS_TX_TRAINING_STAGE_NORMAL_OPERATION = 0,
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V22BIS_TX_TRAINING_STAGE_INITIAL_TIMED_SILENCE,
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V22BIS_TX_TRAINING_STAGE_INITIAL_SILENCE,
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V22BIS_TX_TRAINING_STAGE_U11,
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V22BIS_TX_TRAINING_STAGE_U0011,
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V22BIS_TX_TRAINING_STAGE_S11,
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V22BIS_TX_TRAINING_STAGE_TIMED_S11,
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V22BIS_TX_TRAINING_STAGE_S1111,
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V22BIS_TX_TRAINING_STAGE_PARKED
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};
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#if defined(SPANDSP_USE_FIXED_POINT)
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extern const complexi16_t v22bis_constellation[16];
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#else
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extern const complexf_t v22bis_constellation[16];
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#endif
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/*!
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V.22bis modem descriptor. This defines the working state for a single instance
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of a V.22bis modem.
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*/
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struct v22bis_state_s
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{
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/*! \brief The maximum permitted bit rate of the modem. Valid values are 1200 and 2400. */
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int bit_rate;
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/*! \brief TRUE is this is the calling side modem. */
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int calling_party;
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/*! \brief The callback function used to get the next bit to be transmitted. */
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get_bit_func_t get_bit;
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/*! \brief A user specified opaque pointer passed to the get_bit callback routine. */
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void *get_bit_user_data;
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/*! \brief The callback function used to put each bit received. */
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put_bit_func_t put_bit;
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/*! \brief A user specified opaque pointer passed to the put_bit callback routine. */
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void *put_bit_user_data;
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/*! \brief The callback function used to report modem status changes. */
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modem_status_func_t status_handler;
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/*! \brief A user specified opaque pointer passed to the status function. */
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void *status_user_data;
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int negotiated_bit_rate;
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/* Receive section */
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struct
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{
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/*! \brief Current offset into the RRC pulse shaping filter buffer. */
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int rrc_filter_step;
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/*! \brief The register for the data scrambler. */
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uint32_t scramble_reg;
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/*! \brief A counter for the number of consecutive bits of repeating pattern through
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the scrambler. */
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int scrambler_pattern_count;
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/*! \brief 0 if receiving user data. A training stage value during training */
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int training;
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/*! \brief A count of how far through the current training step we are. */
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int training_count;
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/*! \brief >0 if a signal above the minimum is present. It may or may not be a V.22bis signal. */
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int signal_present;
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/*! \brief The current phase of the carrier (i.e. the DDS parameter). */
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uint32_t carrier_phase;
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/*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
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int32_t carrier_phase_rate;
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/*! \brief A callback function which may be enabled to report every symbol's
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constellation position. */
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qam_report_handler_t qam_report;
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/*! \brief A user specified opaque pointer passed to the qam_report callback
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routine. */
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void *qam_user_data;
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/*! \brief A power meter, to measure the HPF'ed signal power in the channel. */
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power_meter_t rx_power;
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/*! \brief The power meter level at which carrier on is declared. */
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int32_t carrier_on_power;
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/*! \brief The power meter level at which carrier off is declared. */
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int32_t carrier_off_power;
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int constellation_state;
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#if defined(SPANDSP_USE_FIXED_POINT)
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/*! \brief The scaling factor accessed by the AGC algorithm. */
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int16_t agc_scaling;
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/*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
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int16_t rrc_filter[V22BIS_RX_FILTER_STEPS];
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/*! \brief The current delta factor for updating the equalizer coefficients. */
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int16_t eq_delta;
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/*! \brief The adaptive equalizer coefficients. */
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complexi16_t eq_coeff[V22BIS_EQUALIZER_LEN];
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/*! \brief The equalizer signal buffer. */
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complexi16_t eq_buf[V22BIS_EQUALIZER_LEN];
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/*! \brief A measure of how much mismatch there is between the real constellation,
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and the decoded symbol positions. */
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int32_t training_error;
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/*! \brief The proportional part of the carrier tracking filter. */
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int32_t carrier_track_p;
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/*! \brief The integral part of the carrier tracking filter. */
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int32_t carrier_track_i;
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#else
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/*! \brief The scaling factor accessed by the AGC algorithm. */
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float agc_scaling;
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/*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
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float rrc_filter[V22BIS_RX_FILTER_STEPS];
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/*! \brief The current delta factor for updating the equalizer coefficients. */
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float eq_delta;
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/*! \brief The adaptive equalizer coefficients. */
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complexf_t eq_coeff[V22BIS_EQUALIZER_LEN];
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/*! \brief The equalizer signal buffer. */
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complexf_t eq_buf[V22BIS_EQUALIZER_LEN];
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/*! \brief A measure of how much mismatch there is between the real constellation,
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and the decoded symbol positions. */
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float training_error;
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/*! \brief The proportional part of the carrier tracking filter. */
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float carrier_track_p;
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/*! \brief The integral part of the carrier tracking filter. */
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float carrier_track_i;
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#endif
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/*! \brief Current offset into the equalizer buffer. */
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int eq_step;
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/*! \brief Current write offset into the equalizer buffer. */
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int eq_put_step;
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/*! \brief Integration variable for damping the Gardner algorithm tests. */
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int gardner_integrate;
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/*! \brief Current step size of Gardner algorithm integration. */
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int gardner_step;
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/*! \brief The total symbol timing correction since the carrier came up.
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This is only for performance analysis purposes. */
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int total_baud_timing_correction;
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/*! \brief The current fractional phase of the baud timing. */
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int baud_phase;
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int sixteen_way_decisions;
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int pattern_repeats;
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int last_raw_bits;
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} rx;
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/* Transmit section */
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struct
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{
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#if defined(SPANDSP_USE_FIXED_POINT)
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/*! \brief The guard tone level. */
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int16_t guard_tone_gain;
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/*! \brief The gain factor needed to achieve the specified output power. */
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int16_t gain;
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/*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
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int16_t rrc_filter_re[V22BIS_TX_FILTER_STEPS];
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int16_t rrc_filter_im[V22BIS_TX_FILTER_STEPS];
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#else
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/*! \brief The guard tone level. */
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float guard_tone_gain;
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/*! \brief The gain factor needed to achieve the specified output power. */
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float gain;
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/*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
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float rrc_filter_re[V22BIS_TX_FILTER_STEPS];
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float rrc_filter_im[V22BIS_TX_FILTER_STEPS];
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#endif
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/*! \brief Current offset into the RRC pulse shaping filter buffer. */
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int rrc_filter_step;
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/*! \brief The register for the data scrambler. */
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uint32_t scramble_reg;
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/*! \brief A counter for the number of consecutive bits of repeating pattern through
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the scrambler. */
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int scrambler_pattern_count;
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/*! \brief 0 if transmitting user data. A training stage value during training */
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int training;
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/*! \brief A counter used to track progress through sending the training sequence. */
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int training_count;
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/*! \brief The current phase of the carrier (i.e. the DDS parameter). */
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uint32_t carrier_phase;
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/*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
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int32_t carrier_phase_rate;
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/*! \brief The current phase of the guard tone (i.e. the DDS parameter). */
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uint32_t guard_phase;
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/*! \brief The update rate for the phase of the guard tone (i.e. the DDS increment). */
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int32_t guard_phase_rate;
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/*! \brief The current fractional phase of the baud timing. */
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int baud_phase;
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/*! \brief The code number for the current position in the constellation. */
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int constellation_state;
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/*! \brief An indicator to mark that we are tidying up to stop transmission. */
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int shutdown;
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/*! \brief The get_bit function in use at any instant. */
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get_bit_func_t current_get_bit;
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} tx;
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/*! \brief Error and flow logging control */
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logging_state_t logging;
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};
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#if defined(__cplusplus)
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extern "C"
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{
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#endif
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/*! Reinitialise an existing V.22bis modem receive context.
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\brief Reinitialise an existing V.22bis modem receive context.
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\param s The modem context.
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\return 0 for OK, -1 for bad parameter */
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int v22bis_rx_restart(v22bis_state_t *s);
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void v22bis_report_status_change(v22bis_state_t *s, int status);
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void v22bis_equalizer_coefficient_reset(v22bis_state_t *s);
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#if defined(__cplusplus)
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}
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#endif
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#endif
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/*- End of file ------------------------------------------------------------*/
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