v17rx.c File Reference

#include <stdlib.h>
#include <inttypes.h>
#include <string.h>
#include <stdio.h>
#include "floating_fudge.h"
#include "spandsp/telephony.h"
#include "spandsp/logging.h"
#include "spandsp/complex.h"
#include "spandsp/vector_float.h"
#include "spandsp/complex_vector_float.h"
#include "spandsp/vector_int.h"
#include "spandsp/complex_vector_int.h"
#include "spandsp/async.h"
#include "spandsp/power_meter.h"
#include "spandsp/arctan2.h"
#include "spandsp/dds.h"
#include "spandsp/complex_filters.h"
#include "spandsp/v29rx.h"
#include "spandsp/v17tx.h"
#include "spandsp/v17rx.h"
#include "spandsp/private/logging.h"
#include "spandsp/private/v17rx.h"
#include "v17tx_constellation_maps.h"
#include "v17rx_constellation_maps.h"
#include "v17rx_floating_rrc.h"

Defines

#define IAXMODEM_STUFF
#define CARRIER_NOMINAL_FREQ   1800.0f
#define BAUD_RATE   2400
#define EQUALIZER_DELTA   0.21f
#define EQUALIZER_SLOW_ADAPT_RATIO   0.1f
#define V17_TRAINING_SEG_1_LEN   256
#define V17_TRAINING_SEG_2_LEN   2976
#define V17_TRAINING_SHORT_SEG_2_LEN   38
#define V17_TRAINING_SEG_3_LEN   64
#define V17_TRAINING_SEG_4A_LEN   15
#define V17_TRAINING_SEG_4_LEN   48
#define V17_BRIDGE_WORD   0x8880
#define V17_EQUALIZER_LEN   (V17_EQUALIZER_PRE_LEN + 1 + V17_EQUALIZER_POST_LEN)
#define SYNC_LOW_BAND_EDGE_COEFF_0   1.764193f
#define SYNC_LOW_BAND_EDGE_COEFF_1   -0.980100f
#define SYNC_HIGH_BAND_EDGE_COEFF_0   -1.400072f
#define SYNC_HIGH_BAND_EDGE_COEFF_1   -0.980100f
#define SYNC_CROSS_CORR_COEFF_A   -0.932131f
#define SYNC_CROSS_CORR_COEFF_B   0.700036f
#define SYNC_CROSS_CORR_COEFF_C   -0.449451f

Enumerations

enum  {
  TRAINING_STAGE_NORMAL_OPERATION = 0, TRAINING_STAGE_SYMBOL_ACQUISITION, TRAINING_STAGE_LOG_PHASE, TRAINING_STAGE_SHORT_WAIT_FOR_CDBA,
  TRAINING_STAGE_WAIT_FOR_CDBA, TRAINING_STAGE_COARSE_TRAIN_ON_CDBA, TRAINING_STAGE_FINE_TRAIN_ON_CDBA, TRAINING_STAGE_SHORT_TRAIN_ON_CDBA_AND_TEST,
  TRAINING_STAGE_TRAIN_ON_CDBA_AND_TEST, TRAINING_STAGE_BRIDGE, TRAINING_STAGE_TCM_WINDUP, TRAINING_STAGE_TEST_ONES,
  TRAINING_STAGE_PARKED
}

Functions

float v17_rx_carrier_frequency (v17_rx_state_t *s)
float v17_rx_symbol_timing_correction (v17_rx_state_t *s)
float v17_rx_signal_power (v17_rx_state_t *s)
void v17_rx_signal_cutoff (v17_rx_state_t *s, float cutoff)
int v17_rx_equalizer_state (v17_rx_state_t *s, complexf_t **coeffs)
 Get a snapshot of the current equalizer coefficients.
int v17_rx (v17_rx_state_t *s, const int16_t amp[], int len)
 Process a block of received V.17 modem audio samples.
int v17_rx_fillin (v17_rx_state_t *s, int len)
 Fake processing of a missing block of received V.17 modem audio samples.
void v17_rx_set_put_bit (v17_rx_state_t *s, put_bit_func_t put_bit, void *user_data)
 Change the put_bit function associated with a V.17 modem receive context.
void v17_rx_set_modem_status_handler (v17_rx_state_t *s, modem_tx_status_func_t handler, void *user_data)
 Change the modem status report function associated with a V.17 modem receive context.
logging_state_tv17_rx_get_logging_state (v17_rx_state_t *s)
 Get the logging context associated with a V.17 modem receive context.
int v17_rx_restart (v17_rx_state_t *s, int bit_rate, int short_train)
 Reinitialise an existing V.17 modem receive context.
v17_rx_state_tv17_rx_init (v17_rx_state_t *s, int bit_rate, put_bit_func_t put_bit, void *user_data)
 Initialise a V.17 modem receive context.
int v17_rx_release (v17_rx_state_t *s)
 Release a V.17 modem receive context.
int v17_rx_free (v17_rx_state_t *s)
 Free a V.17 modem receive context.
void v17_rx_set_qam_report_handler (v17_rx_state_t *s, qam_report_handler_t handler, void *user_data)

Detailed Description


Define Documentation

#define BAUD_RATE   2400

The nominal baud or symbol rate

#define CARRIER_NOMINAL_FREQ   1800.0f

The nominal frequency of the carrier, in Hertz

Referenced by v17_rx_init(), v17_rx_restart(), v17_tx_init(), v27ter_rx_restart(), v27ter_tx_init(), v29_rx_restart(), and v29_tx_init().

#define EQUALIZER_DELTA   0.21f

The adaption rate coefficient for the equalizer during initial training

#define EQUALIZER_SLOW_ADAPT_RATIO   0.1f

The adaption rate coefficient for the equalizer during continuous fine tuning

#define V17_BRIDGE_WORD   0x8880

The 16 bit pattern used in the bridge section of the training sequence

#define V17_EQUALIZER_LEN   (V17_EQUALIZER_PRE_LEN + 1 + V17_EQUALIZER_POST_LEN)

The length of the equalizer buffer

Referenced by v17_rx_equalizer_state().

#define V17_TRAINING_SEG_1_LEN   256

The length of training segment 1, in symbols

#define V17_TRAINING_SEG_2_LEN   2976

The length of training segment 2 in long training mode, in symbols

#define V17_TRAINING_SEG_3_LEN   64

The length of training segment 3, in symbols

#define V17_TRAINING_SEG_4_LEN   48

The length of training segment 4, in symbols

#define V17_TRAINING_SEG_4A_LEN   15

The length of training segment 4A, in symbols

#define V17_TRAINING_SHORT_SEG_2_LEN   38

The length of training segment 2 in short training mode, in symbols


Function Documentation

int v17_rx ( v17_rx_state_t s,
const int16_t  amp[],
int  len 
)

Process a block of received V.17 modem audio samples.

Process a block of received V.17 modem audio samples.

Parameters:
s The modem context.
amp The audio sample buffer.
len The number of samples in the buffer.
Returns:
The number of samples unprocessed.

References dds_advance(), dds_advancef(), dds_lookup_complexf(), complexf_t::im, power_meter_init(), power_meter_update(), complexf_t::re, SIG_STATUS_CARRIER_DOWN, SIG_STATUS_CARRIER_UP, V17_RX_FILTER_STEPS, v17_rx_restart(), vec_circular_dot_prodf(), and vec_circular_dot_prodi16().

float v17_rx_carrier_frequency ( v17_rx_state_t s  ) 

Get the current received carrier frequency.

Parameters:
s The modem context.
Returns:
The frequency, in Hertz.

References dds_frequencyf().

int v17_rx_equalizer_state ( v17_rx_state_t s,
complexf_t **  coeffs 
)

Get a snapshot of the current equalizer coefficients.

Get a snapshot of the current equalizer coefficients.

Parameters:
s The modem context.
coeffs The vector of complex coefficients.
Returns:
The number of coefficients in the vector.

References V17_EQUALIZER_LEN.

int v17_rx_fillin ( v17_rx_state_t s,
int  len 
)

Fake processing of a missing block of received V.17 modem audio samples.

Fake processing of a missing block of received V.17 modem audio samples. (e.g due to packet loss).

Parameters:
s The modem context.
len The number of samples to fake.
Returns:
The number of samples unprocessed.

References dds_advance(), dds_advancef(), and span_log().

Referenced by fax_rx_fillin(), and t31_rx_fillin().

int v17_rx_free ( v17_rx_state_t s  ) 

Free a V.17 modem receive context.

Free a V.17 modem receive context.

Parameters:
s The modem context.
Returns:
0 for OK

logging_state_t* v17_rx_get_logging_state ( v17_rx_state_t s  ) 

Get the logging context associated with a V.17 modem receive context.

Get the logging context associated with a V.17 modem receive context.

Parameters:
s The modem context.
Returns:
A pointer to the logging context

v17_rx_state_t* v17_rx_init ( v17_rx_state_t s,
int  bit_rate,
put_bit_func_t  put_bit,
void *  user_data 
)

Initialise a V.17 modem receive context.

Initialise a V.17 modem receive context.

Parameters:
s The modem context.
bit_rate The bit rate of the modem. Valid values are 7200, 9600, 12000 and 14400.
put_bit The callback routine used to put the received data.
user_data An opaque pointer passed to the put_bit routine.
Returns:
A pointer to the modem context, or NULL if there was a problem.

References CARRIER_NOMINAL_FREQ, dds_phase_ratef(), v17_rx_restart(), and v17_rx_signal_cutoff().

int v17_rx_release ( v17_rx_state_t s  ) 

Release a V.17 modem receive context.

Release a V.17 modem receive context.

Parameters:
s The modem context.
Returns:
0 for OK

int v17_rx_restart ( v17_rx_state_t s,
int  bit_rate,
int  short_train 
)

Reinitialise an existing V.17 modem receive context.

Reinitialise an existing V.17 modem receive context.

Parameters:
s The modem context.
bit_rate The bit rate of the modem. Valid values are 7200, 9600, 12000 and 14400.
short_train TRUE if a short training sequence is expected.
Returns:
0 for OK, -1 for bad parameter

References CARRIER_NOMINAL_FREQ, dds_frequencyf(), dds_phase_ratef(), power_meter_init(), and span_log().

Referenced by v17_rx(), and v17_rx_init().

void v17_rx_set_modem_status_handler ( v17_rx_state_t s,
modem_rx_status_func_t  handler,
void *  user_data 
)

Change the modem status report function associated with a V.17 modem receive context.

Change the modem status report function associated with a V.17 modem receive context.

Parameters:
s The modem context.
handler The callback routine used to report modem status changes.
user_data An opaque pointer.

void v17_rx_set_put_bit ( v17_rx_state_t s,
put_bit_func_t  put_bit,
void *  user_data 
)

Change the put_bit function associated with a V.17 modem receive context.

Change the put_bit function associated with a V.17 modem receive context.

Parameters:
s The modem context.
put_bit The callback routine used to handle received bits.
user_data An opaque pointer.

void v17_rx_set_qam_report_handler ( v17_rx_state_t s,
qam_report_handler_t  handler,
void *  user_data 
)

Set a handler routine to process QAM status reports

Parameters:
s The modem context.
handler The handler routine.
user_data An opaque pointer passed to the handler routine.

void v17_rx_signal_cutoff ( v17_rx_state_t s,
float  cutoff 
)

Set the power level at which the carrier detection will cut in

Parameters:
s The modem context.
cutoff The signal cutoff power, in dBm0.

References power_meter_level_dbm0().

Referenced by v17_rx_init().

float v17_rx_signal_power ( v17_rx_state_t s  ) 

Get a current received signal power.

Parameters:
s The modem context.
Returns:
The signal power, in dBm0.

References power_meter_current_dbm0().

float v17_rx_symbol_timing_correction ( v17_rx_state_t s  ) 

Get the current symbol timing correction since startup.

Parameters:
s The modem context.
Returns:
The correction.


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