spandsp  3.0.0
private/v22bis.h
1 /*
2  * SpanDSP - a series of DSP components for telephony
3  *
4  * private/v22bis.h - ITU V.22bis modem
5  *
6  * Written by Steve Underwood <steveu@coppice.org>
7  *
8  * Copyright (C) 2004 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 
26 #if !defined(_SPANDSP_PRIVATE_V22BIS_H_)
27 #define _SPANDSP_PRIVATE_V22BIS_H_
28 
29 /*! The length of the equalizer buffer */
30 #define V22BIS_EQUALIZER_LEN 17
31 /*! Samples before the target position in the equalizer buffer */
32 #define V22BIS_EQUALIZER_PRE_LEN 8
33 
34 /*! The number of taps in the transmit pulse shaping filter */
35 #define V22BIS_TX_FILTER_STEPS 9
36 
37 /*! The number of taps in the receive pulse shaping/bandpass filter */
38 #define V22BIS_RX_FILTER_STEPS 27
39 
40 /*! Segments of the training sequence on the receive side */
41 enum
42 {
43  V22BIS_RX_TRAINING_STAGE_NORMAL_OPERATION,
44  V22BIS_RX_TRAINING_STAGE_SYMBOL_ACQUISITION,
45  V22BIS_RX_TRAINING_STAGE_LOG_PHASE,
46  V22BIS_RX_TRAINING_STAGE_UNSCRAMBLED_ONES,
47  V22BIS_RX_TRAINING_STAGE_UNSCRAMBLED_ONES_SUSTAINING,
48  V22BIS_RX_TRAINING_STAGE_SCRAMBLED_ONES_AT_1200,
49  V22BIS_RX_TRAINING_STAGE_SCRAMBLED_ONES_AT_1200_SUSTAINING,
50  V22BIS_RX_TRAINING_STAGE_WAIT_FOR_SCRAMBLED_ONES_AT_2400,
51  V22BIS_RX_TRAINING_STAGE_PARKED
52 };
53 
54 /*! Segments of the training sequence on the transmit side */
55 enum
56 {
57  V22BIS_TX_TRAINING_STAGE_NORMAL_OPERATION = 0,
58  V22BIS_TX_TRAINING_STAGE_INITIAL_SILENCE, /* Initial calling side state */
59  V22BIS_TX_TRAINING_STAGE_INITIAL_TIMED_SILENCE, /* Initial V,22bis answering side state */
60  V22BIS_TX_TRAINING_STAGE_U11,
61  V22BIS_TX_TRAINING_STAGE_U00, /* A special feature for testing purposes. */
62  V22BIS_TX_TRAINING_STAGE_U0011,
63  V22BIS_TX_TRAINING_STAGE_S11,
64  V22BIS_TX_TRAINING_STAGE_TIMED_S11,
65  V22BIS_TX_TRAINING_STAGE_S1111,
66  V22BIS_TX_TRAINING_STAGE_PARKED
67 };
68 
69 #if defined(SPANDSP_USE_FIXED_POINT)
70 extern const complexi16_t v22bis_constellation[16];
71 #else
72 extern const complexf_t v22bis_constellation[16];
73 #endif
74 
75 /*!
76  V.22bis modem descriptor. This defines the working state for a single instance
77  of a V.22bis modem.
78 */
80 {
81  /*! \brief The maximum permitted bit rate of the modem. Valid values are 1200 and 2400. */
82  int bit_rate;
83  /*! \brief Guard tone and sundry flags */
84  int options;
85  /*! \brief True if this is the calling side modem. */
87  /*! \brief The callback function used to get the next bit to be transmitted. */
89  /*! \brief A user specified opaque pointer passed to the get_bit callback routine. */
91  /*! \brief The callback function used to put each bit received. */
93  /*! \brief A user specified opaque pointer passed to the put_bit callback routine. */
95  /*! \brief The callback function used to report modem status changes. */
97  /*! \brief A user specified opaque pointer passed to the status function. */
99 
100  int negotiated_bit_rate;
101 
102  /* Receive section */
103  struct
104  {
105  /*! \brief Current offset into the RRC pulse shaping filter buffer. */
107 
108  /*! \brief The register for the data scrambler. */
109  uint32_t scramble_reg;
110  /*! \brief A counter for the number of consecutive bits of repeating pattern through
111  the scrambler. */
113 
114  /*! \brief 0 if receiving user data. A training stage value during training */
115  int training;
116  /*! \brief A count of how far through the current training step we are. */
118 
119  /*! \brief >0 if a signal above the minimum is present. It may or may not be a V.22bis signal. */
121 
122  /*! \brief The current phase of the carrier (i.e. the DDS parameter). */
123  uint32_t carrier_phase;
124  /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
126 
127  /*! \brief A callback function which may be enabled to report every symbol's
128  constellation position. */
129  qam_report_handler_t qam_report;
130  /*! \brief A user specified opaque pointer passed to the qam_report callback
131  routine. */
133 
134  /*! \brief A power meter, to measure the HPF'ed signal power in the channel. */
136  /*! \brief The power meter level at which carrier on is declared. */
138  /*! \brief The power meter level at which carrier off is declared. */
140 
142 
143 #if defined(SPANDSP_USE_FIXED_POINT)
144  /*! \brief The scaling factor assessed by the AGC algorithm. */
145  int16_t agc_scaling;
146  /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
147  int16_t rrc_filter[V22BIS_RX_FILTER_STEPS];
148 
149  /*! \brief The current delta factor for updating the equalizer coefficients. */
150  int16_t eq_delta;
151  /*! \brief The adaptive equalizer coefficients. */
152  complexi16_t eq_coeff[V22BIS_EQUALIZER_LEN];
153  /*! \brief The equalizer signal buffer. */
154  complexi16_t eq_buf[V22BIS_EQUALIZER_LEN];
155 
156  /*! \brief A measure of how much mismatch there is between the real constellation,
157  and the decoded symbol positions. */
158  int32_t training_error;
159  /*! \brief The proportional part of the carrier tracking filter. */
160  int32_t carrier_track_p;
161  /*! \brief The integral part of the carrier tracking filter. */
162  int32_t carrier_track_i;
163 #else
164  /*! \brief The scaling factor assessed by the AGC algorithm. */
165  float agc_scaling;
166  /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
167  float rrc_filter[V22BIS_RX_FILTER_STEPS];
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[V22BIS_EQUALIZER_LEN];
173  /*! \brief The equalizer signal buffer. */
174  complexf_t eq_buf[V22BIS_EQUALIZER_LEN];
175 
176  /*! \brief A measure of how much mismatch there is between the real constellation,
177  and the decoded symbol positions. */
179  /*! \brief The proportional part of the carrier tracking filter. */
181  /*! \brief The integral part of the carrier tracking filter. */
183 #endif
184  /*! \brief Current offset into the equalizer buffer. */
185  int eq_step;
186  /*! \brief Current write offset into the equalizer buffer. */
188 
189  /*! \brief Integration variable for damping the Gardner algorithm tests. */
191  /*! \brief Current step size of Gardner algorithm integration. */
193  /*! \brief The total symbol timing correction since the carrier came up.
194  This is only for performance analysis purposes. */
196  /*! \brief The current fractional phase of the baud timing. */
198 
199  int sixteen_way_decisions;
200 
201  int pattern_repeats;
202  int last_raw_bits;
203  } rx;
204 
205  /* Transmit section */
206  struct
207  {
208 #if defined(SPANDSP_USE_FIXED_POINT)
209  /*! \brief The guard tone level. */
210  int16_t guard_tone_gain;
211  /*! \brief The gain factor needed to achieve the specified output power. */
212  int16_t gain;
213  /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
214  int16_t rrc_filter_re[V22BIS_TX_FILTER_STEPS];
215  int16_t rrc_filter_im[V22BIS_TX_FILTER_STEPS];
216 #else
217  /*! \brief The guard tone level. */
219  /*! \brief The gain factor needed to achieve the specified output power. */
220  float gain;
221  /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
222  float rrc_filter_re[V22BIS_TX_FILTER_STEPS];
223  float rrc_filter_im[V22BIS_TX_FILTER_STEPS];
224 #endif
225 
226  /*! \brief Current offset into the RRC pulse shaping filter buffer. */
227  int rrc_filter_step;
228 
229  /*! \brief The register for the data scrambler. */
230  uint32_t scramble_reg;
231  /*! \brief A counter for the number of consecutive bits of repeating pattern through
232  the scrambler. */
234 
235  /*! \brief 0 if transmitting user data. A training stage value during training */
236  int training;
237  /*! \brief A counter used to track progress through sending the training sequence. */
238  int training_count;
239  /*! \brief The current phase of the carrier (i.e. the DDS parameter). */
240  uint32_t carrier_phase;
241  /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
242  int32_t carrier_phase_rate;
243  /*! \brief The current phase of the guard tone (i.e. the DDS parameter). */
245  /*! \brief The update rate for the phase of the guard tone (i.e. the DDS increment). */
247  /*! \brief The current fractional phase of the baud timing. */
248  int baud_phase;
249  /*! \brief The code number for the current position in the constellation. */
251  /*! \brief An indicator to mark that we are tidying up to stop transmission. */
252  int shutdown;
253  /*! \brief The get_bit function in use at any instant. */
255  } tx;
256 
257  /*! \brief Error and flow logging control */
259 };
260 
261 #if defined(__cplusplus)
262 extern "C"
263 {
264 #endif
265 
266 /*! Reinitialise an existing V.22bis modem receive context.
267  \brief Reinitialise an existing V.22bis modem receive context.
268  \param s The modem context.
269  \return 0 for OK, -1 for bad parameter */
271 
272 void v22bis_report_status_change(v22bis_state_t *s, int status);
273 
274 void v22bis_equalizer_coefficient_reset(v22bis_state_t *s);
275 
276 #if defined(__cplusplus)
277 }
278 #endif
279 
280 #endif
281 /*- End of file ------------------------------------------------------------*/
power_meter_t rx_power
A power meter, to measure the HPF&#39;ed signal power in the channel.
Definition: private/v22bis.h:135
uint32_t guard_tone_phase
The current phase of the guard tone (i.e. the DDS parameter).
Definition: private/v22bis.h:244
Definition: private/power_meter.h:33
float rrc_filter_re[9]
The root raised cosine (RRC) pulse shaping filter buffer.
Definition: private/v22bis.h:222
float eq_delta
The current delta factor for updating the equalizer coefficients.
Definition: private/v22bis.h:170
Definition: complex.h:88
qam_report_handler_t qam_report
A callback function which may be enabled to report every symbol&#39;s constellation position.
Definition: private/v22bis.h:129
int shutdown
An indicator to mark that we are tidying up to stop transmission.
Definition: private/v22bis.h:252
uint32_t scramble_reg
The register for the data scrambler.
Definition: private/v22bis.h:109
float gain
The gain factor needed to achieve the specified output power.
Definition: private/v22bis.h:220
int32_t carrier_on_power
The power meter level at which carrier on is declared.
Definition: private/v22bis.h:137
int scrambler_pattern_count
A counter for the number of consecutive bits of repeating pattern through the scrambler.
Definition: private/v22bis.h:112
logging_state_t logging
Error and flow logging control.
Definition: private/v22bis.h:258
span_modem_status_func_t status_handler
The callback function used to report modem status changes.
Definition: private/v22bis.h:96
int(* span_get_bit_func_t)(void *user_data)
Definition: async.h:127
uint32_t carrier_phase
The current phase of the carrier (i.e. the DDS parameter).
Definition: private/v22bis.h:123
int gardner_step
Current step size of Gardner algorithm integration.
Definition: private/v22bis.h:192
float training_error
A measure of how much mismatch there is between the real constellation, and the decoded symbol positi...
Definition: private/v22bis.h:178
int bit_rate
The maximum permitted bit rate of the modem. Valid values are 1200 and 2400.
Definition: private/v22bis.h:82
int32_t carrier_off_power
The power meter level at which carrier off is declared.
Definition: private/v22bis.h:139
int gardner_integrate
Integration variable for damping the Gardner algorithm tests.
Definition: private/v22bis.h:190
float carrier_track_p
The proportional part of the carrier tracking filter.
Definition: private/v22bis.h:180
void(* span_modem_status_func_t)(void *user_data, int status)
Definition: async.h:131
void(* span_put_bit_func_t)(void *user_data, int bit)
Definition: async.h:123
int signal_present
>0 if a signal above the minimum is present. It may or may not be a V.22bis signal.
Definition: private/v22bis.h:120
span_get_bit_func_t current_get_bit
The get_bit function in use at any instant.
Definition: private/v22bis.h:254
int training_count
A count of how far through the current training step we are.
Definition: private/v22bis.h:117
span_put_bit_func_t put_bit
The callback function used to put each bit received.
Definition: private/v22bis.h:92
void * status_user_data
A user specified opaque pointer passed to the status function.
Definition: private/v22bis.h:98
int training
0 if receiving user data. A training stage value during training
Definition: private/v22bis.h:115
int v22bis_rx_restart(v22bis_state_t *s)
Reinitialise an existing V.22bis modem receive context.
Definition: v22bis_rx.c:1006
float carrier_track_i
The integral part of the carrier tracking filter.
Definition: private/v22bis.h:182
complexf_t eq_coeff[17]
The adaptive equalizer coefficients.
Definition: private/v22bis.h:172
void * get_bit_user_data
A user specified opaque pointer passed to the get_bit callback routine.
Definition: private/v22bis.h:90
void * qam_user_data
A user specified opaque pointer passed to the qam_report callback routine.
Definition: private/v22bis.h:132
void * put_bit_user_data
A user specified opaque pointer passed to the put_bit callback routine.
Definition: private/v22bis.h:94
Definition: complex.h:42
int rrc_filter_step
Current offset into the RRC pulse shaping filter buffer.
Definition: private/v22bis.h:106
Definition: private/logging.h:33
int baud_phase
The current fractional phase of the baud timing.
Definition: private/v22bis.h:197
Definition: private/v22bis.h:79
int options
Guard tone and sundry flags.
Definition: private/v22bis.h:84
int constellation_state
The code number for the current position in the constellation.
Definition: private/v22bis.h:141
int32_t guard_tone_phase_rate
The update rate for the phase of the guard tone (i.e. the DDS increment).
Definition: private/v22bis.h:246
float rrc_filter[27]
The root raised cosine (RRC) pulse shaping filter buffer.
Definition: private/v22bis.h:167
span_get_bit_func_t get_bit
The callback function used to get the next bit to be transmitted.
Definition: private/v22bis.h:88
int total_baud_timing_correction
The total symbol timing correction since the carrier came up. This is only for performance analysis p...
Definition: private/v22bis.h:195
float agc_scaling
The scaling factor assessed by the AGC algorithm.
Definition: private/v22bis.h:165
bool calling_party
True if this is the calling side modem.
Definition: private/v22bis.h:86
complexf_t eq_buf[17]
The equalizer signal buffer.
Definition: private/v22bis.h:174
int32_t carrier_phase_rate
The update rate for the phase of the carrier (i.e. the DDS increment).
Definition: private/v22bis.h:125
float guard_tone_gain
The guard tone level.
Definition: private/v22bis.h:218
int eq_put_step
Current write offset into the equalizer buffer.
Definition: private/v22bis.h:187
int eq_step
Current offset into the equalizer buffer.
Definition: private/v22bis.h:185