private/v17tx.h

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00001 /*
00002  * SpanDSP - a series of DSP components for telephony
00003  *
00004  * private/v17tx.h - ITU V.17 modem transmit part
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 
00026 /*! \file */
00027 
00028 #if !defined(_SPANDSP_PRIVATE_V17TX_H_)
00029 #define _SPANDSP_PRIVATE_V17TX_H_
00030 
00031 /*! The number of taps in the pulse shaping/bandpass filter */
00032 #define V17_TX_FILTER_STEPS     9
00033 
00034 /*!
00035     V.17 modem transmit side descriptor. This defines the working state for a
00036     single instance of a V.17 modem transmitter.
00037 */
00038 struct v17_tx_state_s
00039 {
00040     /*! \brief The bit rate of the modem. Valid values are 4800, 7200 and 9600. */
00041     int bit_rate;
00042     /*! \brief The callback function used to get the next bit to be transmitted. */
00043     get_bit_func_t get_bit;
00044     /*! \brief A user specified opaque pointer passed to the get_bit function. */
00045     void *get_bit_user_data;
00046 
00047     /*! \brief The callback function used to report modem status changes. */
00048     modem_tx_status_func_t status_handler;
00049     /*! \brief A user specified opaque pointer passed to the status function. */
00050     void *status_user_data;
00051 
00052     /*! \brief The gain factor needed to achieve the specified output power. */
00053 #if defined(SPANDSP_USE_FIXED_POINT)
00054     int32_t gain;
00055 #else
00056     float gain;
00057 #endif
00058 
00059     /*! \brief The route raised cosine (RRC) pulse shaping filter buffer. */
00060 #if defined(SPANDSP_USE_FIXED_POINT)
00061     complexi16_t rrc_filter[2*V17_TX_FILTER_STEPS];
00062 #else
00063     complexf_t rrc_filter[2*V17_TX_FILTER_STEPS];
00064 #endif
00065     /*! \brief Current offset into the RRC pulse shaping filter buffer. */
00066     int rrc_filter_step;
00067 
00068     /*! \brief The current state of the differential encoder. */
00069     int diff;
00070     /*! \brief The current state of the convolutional encoder. */
00071     int convolution;
00072     /*! \brief The code number for the current position in the constellation. */
00073     int constellation_state;
00074 
00075     /*! \brief The register for the data scrambler. */
00076     uint32_t scramble_reg;
00077     /*! \brief Scrambler tap */
00078     //int scrambler_tap;
00079     /*! \brief TRUE if transmitting the training sequence. FALSE if transmitting user data. */
00080     int in_training;
00081     /*! \brief TRUE if the short training sequence is to be used. */
00082     int short_train;
00083     /*! \brief A counter used to track progress through sending the training sequence. */
00084     int training_step;
00085 
00086     /*! \brief The current phase of the carrier (i.e. the DDS parameter). */
00087     uint32_t carrier_phase;
00088     /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
00089     int32_t carrier_phase_rate;
00090     /*! \brief The current fractional phase of the baud timing. */
00091     int baud_phase;
00092     
00093     /*! \brief A pointer to the constellation currently in use. */
00094 #if defined(SPANDSP_USE_FIXED_POINT)
00095     const complexi16_t *constellation;
00096 #else
00097     const complexf_t *constellation;
00098 #endif
00099     /*! \brief The current number of data bits per symbol. This does not include
00100                the redundant bit. */
00101     int bits_per_symbol;
00102     /*! \brief The get_bit function in use at any instant. */
00103     get_bit_func_t current_get_bit;
00104     /*! \brief Error and flow logging control */
00105     logging_state_t logging;
00106 };
00107 
00108 #endif
00109 /*- End of file ------------------------------------------------------------*/

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