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_TIMED_SILENCE,
59  V22BIS_TX_TRAINING_STAGE_INITIAL_SILENCE,
60  V22BIS_TX_TRAINING_STAGE_U11,
61  V22BIS_TX_TRAINING_STAGE_U0011,
62  V22BIS_TX_TRAINING_STAGE_S11,
63  V22BIS_TX_TRAINING_STAGE_TIMED_S11,
64  V22BIS_TX_TRAINING_STAGE_S1111,
65  V22BIS_TX_TRAINING_STAGE_PARKED
66 };
67 
68 #if defined(SPANDSP_USE_FIXED_POINT)
69 extern const complexi16_t v22bis_constellation[16];
70 #else
71 extern const complexf_t v22bis_constellation[16];
72 #endif
73 
74 /*!
75  V.22bis modem descriptor. This defines the working state for a single instance
76  of a V.22bis modem.
77 */
79 {
80  /*! \brief The maximum permitted bit rate of the modem. Valid values are 1200 and 2400. */
81  int bit_rate;
82  /*! \brief True is this is the calling side modem. */
84  /*! \brief The callback function used to get the next bit to be transmitted. */
86  /*! \brief A user specified opaque pointer passed to the get_bit callback routine. */
88  /*! \brief The callback function used to put each bit received. */
90  /*! \brief A user specified opaque pointer passed to the put_bit callback routine. */
92  /*! \brief The callback function used to report modem status changes. */
94  /*! \brief A user specified opaque pointer passed to the status function. */
96 
97  int negotiated_bit_rate;
98 
99  /* Receive section */
100  struct
101  {
102  /*! \brief Current offset into the RRC pulse shaping filter buffer. */
104 
105  /*! \brief The register for the data scrambler. */
106  uint32_t scramble_reg;
107  /*! \brief A counter for the number of consecutive bits of repeating pattern through
108  the scrambler. */
110 
111  /*! \brief 0 if receiving user data. A training stage value during training */
112  int training;
113  /*! \brief A count of how far through the current training step we are. */
115 
116  /*! \brief >0 if a signal above the minimum is present. It may or may not be a V.22bis signal. */
118 
119  /*! \brief The current phase of the carrier (i.e. the DDS parameter). */
120  uint32_t carrier_phase;
121  /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
123 
124  /*! \brief A callback function which may be enabled to report every symbol's
125  constellation position. */
126  qam_report_handler_t qam_report;
127  /*! \brief A user specified opaque pointer passed to the qam_report callback
128  routine. */
130 
131  /*! \brief A power meter, to measure the HPF'ed signal power in the channel. */
133  /*! \brief The power meter level at which carrier on is declared. */
135  /*! \brief The power meter level at which carrier off is declared. */
137 
139 
140 #if defined(SPANDSP_USE_FIXED_POINT)
141  /*! \brief The scaling factor assessed by the AGC algorithm. */
142  int16_t agc_scaling;
143  /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
144  int16_t rrc_filter[V22BIS_RX_FILTER_STEPS];
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[V22BIS_EQUALIZER_LEN];
150  /*! \brief The equalizer signal buffer. */
151  complexi16_t eq_buf[V22BIS_EQUALIZER_LEN];
152 
153  /*! \brief A measure of how much mismatch there is between the real constellation,
154  and the decoded symbol positions. */
155  int32_t training_error;
156  /*! \brief The proportional part of the carrier tracking filter. */
157  int32_t carrier_track_p;
158  /*! \brief The integral part of the carrier tracking filter. */
159  int32_t carrier_track_i;
160 #else
161  /*! \brief The scaling factor assessed by the AGC algorithm. */
162  float agc_scaling;
163  /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
164  float rrc_filter[V22BIS_RX_FILTER_STEPS];
165 
166  /*! \brief The current delta factor for updating the equalizer coefficients. */
167  float eq_delta;
168  /*! \brief The adaptive equalizer coefficients. */
169  complexf_t eq_coeff[V22BIS_EQUALIZER_LEN];
170  /*! \brief The equalizer signal buffer. */
171  complexf_t eq_buf[V22BIS_EQUALIZER_LEN];
172 
173  /*! \brief A measure of how much mismatch there is between the real constellation,
174  and the decoded symbol positions. */
176  /*! \brief The proportional part of the carrier tracking filter. */
178  /*! \brief The integral part of the carrier tracking filter. */
180 #endif
181  /*! \brief Current offset into the equalizer buffer. */
182  int eq_step;
183  /*! \brief Current write offset into the equalizer buffer. */
185 
186  /*! \brief Integration variable for damping the Gardner algorithm tests. */
188  /*! \brief Current step size of Gardner algorithm integration. */
190  /*! \brief The total symbol timing correction since the carrier came up.
191  This is only for performance analysis purposes. */
193  /*! \brief The current fractional phase of the baud timing. */
195 
196  int sixteen_way_decisions;
197 
198  int pattern_repeats;
199  int last_raw_bits;
200  } rx;
201 
202  /* Transmit section */
203  struct
204  {
205 #if defined(SPANDSP_USE_FIXED_POINT)
206  /*! \brief The guard tone level. */
207  int16_t guard_tone_gain;
208  /*! \brief The gain factor needed to achieve the specified output power. */
209  int16_t gain;
210  /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
211  int16_t rrc_filter_re[V22BIS_TX_FILTER_STEPS];
212  int16_t rrc_filter_im[V22BIS_TX_FILTER_STEPS];
213 #else
214  /*! \brief The guard tone level. */
216  /*! \brief The gain factor needed to achieve the specified output power. */
217  float gain;
218  /*! \brief The root raised cosine (RRC) pulse shaping filter buffer. */
219  float rrc_filter_re[V22BIS_TX_FILTER_STEPS];
220  float rrc_filter_im[V22BIS_TX_FILTER_STEPS];
221 #endif
222 
223  /*! \brief Current offset into the RRC pulse shaping filter buffer. */
224  int rrc_filter_step;
225 
226  /*! \brief The register for the data scrambler. */
227  uint32_t scramble_reg;
228  /*! \brief A counter for the number of consecutive bits of repeating pattern through
229  the scrambler. */
231 
232  /*! \brief 0 if transmitting user data. A training stage value during training */
233  int training;
234  /*! \brief A counter used to track progress through sending the training sequence. */
235  int training_count;
236  /*! \brief The current phase of the carrier (i.e. the DDS parameter). */
237  uint32_t carrier_phase;
238  /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
239  int32_t carrier_phase_rate;
240  /*! \brief The current phase of the guard tone (i.e. the DDS parameter). */
241  uint32_t guard_phase;
242  /*! \brief The update rate for the phase of the guard tone (i.e. the DDS increment). */
244  /*! \brief The current fractional phase of the baud timing. */
245  int baud_phase;
246  /*! \brief The code number for the current position in the constellation. */
248  /*! \brief An indicator to mark that we are tidying up to stop transmission. */
249  int shutdown;
250  /*! \brief The get_bit function in use at any instant. */
252  } tx;
253 
254  /*! \brief Error and flow logging control */
256 };
257 
258 #if defined(__cplusplus)
259 extern "C"
260 {
261 #endif
262 
263 /*! Reinitialise an existing V.22bis modem receive context.
264  \brief Reinitialise an existing V.22bis modem receive context.
265  \param s The modem context.
266  \return 0 for OK, -1 for bad parameter */
268 
269 void v22bis_report_status_change(v22bis_state_t *s, int status);
270 
271 void v22bis_equalizer_coefficient_reset(v22bis_state_t *s);
272 
273 #if defined(__cplusplus)
274 }
275 #endif
276 
277 #endif
278 /*- 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:132
Definition: private/power_meter.h:33
float rrc_filter_re[9]
The root raised cosine (RRC) pulse shaping filter buffer.
Definition: private/v22bis.h:219
float eq_delta
The current delta factor for updating the equalizer coefficients.
Definition: private/v22bis.h:167
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:126
int shutdown
An indicator to mark that we are tidying up to stop transmission.
Definition: private/v22bis.h:249
uint32_t scramble_reg
The register for the data scrambler.
Definition: private/v22bis.h:106
float gain
The gain factor needed to achieve the specified output power.
Definition: private/v22bis.h:217
int32_t carrier_on_power
The power meter level at which carrier on is declared.
Definition: private/v22bis.h:134
int scrambler_pattern_count
A counter for the number of consecutive bits of repeating pattern through the scrambler.
Definition: private/v22bis.h:109
logging_state_t logging
Error and flow logging control.
Definition: private/v22bis.h:255
uint32_t carrier_phase
The current phase of the carrier (i.e. the DDS parameter).
Definition: private/v22bis.h:120
int gardner_step
Current step size of Gardner algorithm integration.
Definition: private/v22bis.h:189
float training_error
A measure of how much mismatch there is between the real constellation, and the decoded symbol positi...
Definition: private/v22bis.h:175
int bit_rate
The maximum permitted bit rate of the modem. Valid values are 1200 and 2400.
Definition: private/v22bis.h:81
int32_t carrier_off_power
The power meter level at which carrier off is declared.
Definition: private/v22bis.h:136
int gardner_integrate
Integration variable for damping the Gardner algorithm tests.
Definition: private/v22bis.h:187
get_bit_func_t current_get_bit
The get_bit function in use at any instant.
Definition: private/v22bis.h:251
put_bit_func_t put_bit
The callback function used to put each bit received.
Definition: private/v22bis.h:89
float carrier_track_p
The proportional part of the carrier tracking filter.
Definition: private/v22bis.h:177
int32_t guard_phase_rate
The update rate for the phase of the guard tone (i.e. the DDS increment).
Definition: private/v22bis.h:243
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:117
void(* put_bit_func_t)(void *user_data, int bit)
Definition: async.h:107
int training_count
A count of how far through the current training step we are.
Definition: private/v22bis.h:114
modem_status_func_t status_handler
The callback function used to report modem status changes.
Definition: private/v22bis.h:93
get_bit_func_t get_bit
The callback function used to get the next bit to be transmitted.
Definition: private/v22bis.h:85
void * status_user_data
A user specified opaque pointer passed to the status function.
Definition: private/v22bis.h:95
void(* modem_status_func_t)(void *user_data, int status)
Definition: async.h:113
int(* get_bit_func_t)(void *user_data)
Definition: async.h:110
int training
0 if receiving user data. A training stage value during training
Definition: private/v22bis.h:112
int v22bis_rx_restart(v22bis_state_t *s)
Reinitialise an existing V.22bis modem receive context.
Definition: v22bis_rx.c:944
float carrier_track_i
The integral part of the carrier tracking filter.
Definition: private/v22bis.h:179
complexf_t eq_coeff[17]
The adaptive equalizer coefficients.
Definition: private/v22bis.h:169
void * get_bit_user_data
A user specified opaque pointer passed to the get_bit callback routine.
Definition: private/v22bis.h:87
uint32_t guard_phase
The current phase of the guard tone (i.e. the DDS parameter).
Definition: private/v22bis.h:241
void * qam_user_data
A user specified opaque pointer passed to the qam_report callback routine.
Definition: private/v22bis.h:129
void * put_bit_user_data
A user specified opaque pointer passed to the put_bit callback routine.
Definition: private/v22bis.h:91
Definition: complex.h:42
int rrc_filter_step
Current offset into the RRC pulse shaping filter buffer.
Definition: private/v22bis.h:103
Definition: private/logging.h:33
int baud_phase
The current fractional phase of the baud timing.
Definition: private/v22bis.h:194
Definition: private/v22bis.h:78
int constellation_state
The code number for the current position in the constellation.
Definition: private/v22bis.h:138
float rrc_filter[27]
The root raised cosine (RRC) pulse shaping filter buffer.
Definition: private/v22bis.h:164
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:192
float agc_scaling
The scaling factor assessed by the AGC algorithm.
Definition: private/v22bis.h:162
bool calling_party
True is this is the calling side modem.
Definition: private/v22bis.h:83
complexf_t eq_buf[17]
The equalizer signal buffer.
Definition: private/v22bis.h:171
int32_t carrier_phase_rate
The update rate for the phase of the carrier (i.e. the DDS increment).
Definition: private/v22bis.h:122
float guard_tone_gain
The guard tone level.
Definition: private/v22bis.h:215
int eq_put_step
Current write offset into the equalizer buffer.
Definition: private/v22bis.h:184
int eq_step
Current offset into the equalizer buffer.
Definition: private/v22bis.h:182