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comparison spandsp-0.0.6pre17/src/spandsp/private/v29rx.h @ 4:26cd8f1ef0b1

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import spandsp-0.0.6pre17
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 15:50:58 +0200
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3:c6c5a16ce2f2 4:26cd8f1ef0b1
1 /*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * private/v29rx.h - ITU V.29 modem receive part
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2003 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 * $Id: v29rx.h,v 1.2 2009/07/09 13:52:09 steveu Exp $
26 */
27
28 #if !defined(_SPANDSP_PRIVATE_V29RX_H_)
29 #define _SPANDSP_PRIVATE_V29RX_H_
30
31 /* Target length for the equalizer is about 63 taps, to deal with the worst stuff
32 in V.56bis. */
33 /*! Samples before the target position in the equalizer buffer */
34 #define V29_EQUALIZER_PRE_LEN 16
35 /*! Samples after the target position in the equalizer buffer */
36 #define V29_EQUALIZER_POST_LEN 14
37
38 /*! The number of taps in the pulse shaping/bandpass filter */
39 #define V29_RX_FILTER_STEPS 27
40
41 /*!
42 V.29 modem receive side descriptor. This defines the working state for a
43 single instance of a V.29 modem receiver.
44 */
45 struct v29_rx_state_s
46 {
47 /*! \brief The bit rate of the modem. Valid values are 4800, 7200 and 9600. */
48 int bit_rate;
49 /*! \brief The callback function used to put each bit received. */
50 put_bit_func_t put_bit;
51 /*! \brief A user specified opaque pointer passed to the put_bit routine. */
52 void *put_bit_user_data;
53
54 /*! \brief The callback function used to report modem status changes. */
55 modem_rx_status_func_t status_handler;
56 /*! \brief A user specified opaque pointer passed to the status function. */
57 void *status_user_data;
58
59 /*! \brief A callback function which may be enabled to report every symbol's
60 constellation position. */
61 qam_report_handler_t qam_report;
62 /*! \brief A user specified opaque pointer passed to the qam_report callback
63 routine. */
64 void *qam_user_data;
65
66 /*! \brief The route raised cosine (RRC) pulse shaping filter buffer. */
67 #if defined(SPANDSP_USE_FIXED_POINT)
68 int16_t rrc_filter[V29_RX_FILTER_STEPS];
69 #else
70 float rrc_filter[V29_RX_FILTER_STEPS];
71 #endif
72 /*! \brief Current offset into the RRC pulse shaping filter buffer. */
73 int rrc_filter_step;
74
75 /*! \brief The register for the data scrambler. */
76 unsigned int scramble_reg;
77 /*! \brief The register for the training scrambler. */
78 uint8_t training_scramble_reg;
79 /*! \brief The current step in the table of CD constellation positions. */
80 int training_cd;
81 /*! \brief TRUE if the previous trained values are to be reused. */
82 int old_train;
83 /*! \brief The section of the training data we are currently in. */
84 int training_stage;
85 /*! \brief A count of how far through the current training step we are. */
86 int training_count;
87 /*! \brief A measure of how much mismatch there is between the real constellation,
88 and the decoded symbol positions. */
89 float training_error;
90 /*! \brief The value of the last signal sample, using the a simple HPF for signal power estimation. */
91 int16_t last_sample;
92 /*! \brief >0 if a signal above the minimum is present. It may or may not be a V.29 signal. */
93 int signal_present;
94 /*! \brief Whether or not a carrier drop was detected and the signal delivery is pending. */
95 int carrier_drop_pending;
96 /*! \brief A count of the current consecutive samples below the carrier off threshold. */
97 int low_samples;
98 /*! \brief A highest magnitude sample seen. */
99 int16_t high_sample;
100
101 /*! \brief The position of the current symbol in the constellation, used for
102 differential decoding. */
103 int constellation_state;
104
105 /*! \brief The current phase of the carrier (i.e. the DDS parameter). */
106 uint32_t carrier_phase;
107 /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
108 int32_t carrier_phase_rate;
109 /*! \brief The carrier update rate saved for reuse when using short training. */
110 int32_t carrier_phase_rate_save;
111 #if defined(SPANDSP_USE_FIXED_POINT)
112 /*! \brief The proportional part of the carrier tracking filter. */
113 int32_t carrier_track_p;
114 /*! \brief The integral part of the carrier tracking filter. */
115 int32_t carrier_track_i;
116 #else
117 /*! \brief The proportional part of the carrier tracking filter. */
118 float carrier_track_p;
119 /*! \brief The integral part of the carrier tracking filter. */
120 float carrier_track_i;
121 #endif
122
123 /*! \brief A power meter, to measure the HPF'ed signal power in the channel. */
124 power_meter_t power;
125 /*! \brief The power meter level at which carrier on is declared. */
126 int32_t carrier_on_power;
127 /*! \brief The power meter level at which carrier off is declared. */
128 int32_t carrier_off_power;
129
130 /*! \brief Current read offset into the equalizer buffer. */
131 int eq_step;
132 /*! \brief Current write offset into the equalizer buffer. */
133 int eq_put_step;
134 /*! \brief Symbol counter to the next equalizer update. */
135 int eq_skip;
136
137 /*! \brief The current half of the baud. */
138 int baud_half;
139
140 #if defined(SPANDSP_USE_FIXED_POINT)
141 /*! \brief The scaling factor accessed by the AGC algorithm. */
142 int16_t agc_scaling;
143 /*! \brief The previous value of agc_scaling, needed to reuse old training. */
144 int16_t agc_scaling_save;
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[V29_EQUALIZER_PRE_LEN + 1 + V29_EQUALIZER_POST_LEN];
150 /*! \brief A saved set of adaptive equalizer coefficients for use after restarts. */
151 complexi16_t eq_coeff_save[V29_EQUALIZER_PRE_LEN + 1 + V29_EQUALIZER_POST_LEN];
152 /*! \brief The equalizer signal buffer. */
153 complexi16_t eq_buf[V29_EQUALIZER_PRE_LEN + 1 + V29_EQUALIZER_POST_LEN];
154
155 /*! Low band edge filter for symbol sync. */
156 int32_t symbol_sync_low[2];
157 /*! High band edge filter for symbol sync. */
158 int32_t symbol_sync_high[2];
159 /*! DC filter for symbol sync. */
160 int32_t symbol_sync_dc_filter[2];
161 /*! Baud phase for symbol sync. */
162 int32_t baud_phase;
163 #else
164 /*! \brief The scaling factor accessed by the AGC algorithm. */
165 float agc_scaling;
166 /*! \brief The previous value of agc_scaling, needed to reuse old training. */
167 float agc_scaling_save;
168
169 /*! \brief The current delta factor for updating the equalizer coefficients. */
170 float eq_delta;
171 /*! \brief The adaptive equalizer coefficients. */
172 complexf_t eq_coeff[V29_EQUALIZER_PRE_LEN + 1 + V29_EQUALIZER_POST_LEN];
173 /*! \brief A saved set of adaptive equalizer coefficients for use after restarts. */
174 complexf_t eq_coeff_save[V29_EQUALIZER_PRE_LEN + 1 + V29_EQUALIZER_POST_LEN];
175 /*! \brief The equalizer signal buffer. */
176 complexf_t eq_buf[V29_EQUALIZER_PRE_LEN + 1 + V29_EQUALIZER_POST_LEN];
177
178 /*! Low band edge filter for symbol sync. */
179 float symbol_sync_low[2];
180 /*! High band edge filter for symbol sync. */
181 float symbol_sync_high[2];
182 /*! DC filter for symbol sync. */
183 float symbol_sync_dc_filter[2];
184 /*! Baud phase for symbol sync. */
185 float baud_phase;
186 #endif
187
188 /*! \brief The total symbol timing correction since the carrier came up.
189 This is only for performance analysis purposes. */
190 int total_baud_timing_correction;
191
192 /*! \brief Starting phase angles for the coarse carrier aquisition step. */
193 int32_t start_angles[2];
194 /*! \brief History list of phase angles for the coarse carrier aquisition step. */
195 int32_t angles[16];
196 /*! \brief Error and flow logging control */
197 logging_state_t logging;
198 };
199
200 #endif
201 /*- End of file ------------------------------------------------------------*/

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