v27ter_rx.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/v27ter_rx.h"
#include "spandsp/private/logging.h"
#include "spandsp/private/v27ter_rx.h"
#include "v27ter_rx_4800_floating_rrc.h"
#include "v27ter_rx_2400_floating_rrc.h"

Defines

#define IAXMODEM_STUFF
#define CARRIER_NOMINAL_FREQ   1800.0f
#define BAUD_RATE_2400   1200
#define BAUD_RATE_4800   1600
#define EQUALIZER_DELTA   0.25f
#define V27TER_TRAINING_SEG_3_LEN   50
#define V27TER_TRAINING_SEG_5_LEN   1074
#define V27TER_TRAINING_SEG_6_LEN   8
#define V27TER_EQUALIZER_LEN   (V27TER_EQUALIZER_PRE_LEN + 1 + V27TER_EQUALIZER_POST_LEN)

Enumerations

enum  {
  TRAINING_STAGE_NORMAL_OPERATION = 0, TRAINING_STAGE_SYMBOL_ACQUISITION, TRAINING_STAGE_LOG_PHASE, TRAINING_STAGE_WAIT_FOR_HOP,
  TRAINING_STAGE_TRAIN_ON_ABAB, TRAINING_STAGE_TEST_ONES, TRAINING_STAGE_PARKED
}

Functions

float v27ter_rx_carrier_frequency (v27ter_rx_state_t *s)
float v27ter_rx_symbol_timing_correction (v27ter_rx_state_t *s)
float v27ter_rx_signal_power (v27ter_rx_state_t *s)
void v27ter_rx_signal_cutoff (v27ter_rx_state_t *s, float cutoff)
int v27ter_rx_equalizer_state (v27ter_rx_state_t *s, complexf_t **coeffs)
 Get a snapshot of the current equalizer coefficients.
int v27ter_rx (v27ter_rx_state_t *s, const int16_t amp[], int len)
 Process a block of received V.27ter modem audio samples.
int v27ter_rx_fillin (v27ter_rx_state_t *s, int len)
 Fake processing of a missing block of received V.27ter modem audio samples.
void v27ter_rx_set_put_bit (v27ter_rx_state_t *s, put_bit_func_t put_bit, void *user_data)
 Change the put_bit function associated with a V.27ter modem receive context.
void v27ter_rx_set_modem_status_handler (v27ter_rx_state_t *s, modem_tx_status_func_t handler, void *user_data)
 Change the modem status report function associated with a V.27ter modem receive context.
logging_state_tv27ter_rx_get_logging_state (v27ter_rx_state_t *s)
 Get the logging context associated with a V.27ter modem receive context.
int v27ter_rx_restart (v27ter_rx_state_t *s, int bit_rate, int old_train)
 Reinitialise an existing V.27ter modem receive context.
v27ter_rx_state_tv27ter_rx_init (v27ter_rx_state_t *s, int bit_rate, put_bit_func_t put_bit, void *user_data)
 Initialise a V.27ter modem receive context.
int v27ter_rx_release (v27ter_rx_state_t *s)
 Release a V.27ter modem receive context.
int v27ter_rx_free (v27ter_rx_state_t *s)
 Free a V.27ter modem receive context.
void v27ter_rx_set_qam_report_handler (v27ter_rx_state_t *s, qam_report_handler_t handler, void *user_data)

Detailed Description


Define Documentation

#define BAUD_RATE_2400   1200

The nominal baud or symbol rate in 2400bps mode

#define BAUD_RATE_4800   1600

The nominal baud or symbol rate in 4800bps mode

#define CARRIER_NOMINAL_FREQ   1800.0f

The nominal frequency of the carrier, in Hertz

#define EQUALIZER_DELTA   0.25f

The adaption rate coefficient for the equalizer

#define V27TER_EQUALIZER_LEN   (V27TER_EQUALIZER_PRE_LEN + 1 + V27TER_EQUALIZER_POST_LEN)

The length of the equalizer buffer

Referenced by v27ter_rx_equalizer_state().

#define V27TER_TRAINING_SEG_3_LEN   50

The length of training segment 3, in symbols

#define V27TER_TRAINING_SEG_5_LEN   1074

The length of training segment 5, in symbols

#define V27TER_TRAINING_SEG_6_LEN   8

The length of training segment 6, in symbols


Function Documentation

int v27ter_rx ( v27ter_rx_state_t s,
const int16_t  amp[],
int  len 
)

Process a block of received V.27ter modem audio samples.

Process a block of received V.27ter 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 v22bis_state_s::carrier_off_power, v22bis_state_s::carrier_on_power, dds_advance(), dds_advancef(), dds_lookup_complexf(), dds_lookup_complexi16(), complexf_t::im, power_meter_init(), power_meter_update(), complexf_t::re, SIG_STATUS_CARRIER_DOWN, SIG_STATUS_CARRIER_UP, V27TER_RX_2400_FILTER_STEPS, V27TER_RX_4800_FILTER_STEPS, v27ter_rx_restart(), vec_circular_dot_prodf(), and vec_circular_dot_prodi16().

float v27ter_rx_carrier_frequency ( v27ter_rx_state_t s  ) 

Get the current received carrier frequency.

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

References dds_frequencyf().

int v27ter_rx_equalizer_state ( v27ter_rx_state_t s,
complexf_t **  coeffs 
)

Get a snapshot of the current equalizer coefficients.

Get a snapshot of the current equalizer coefficients.

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

References V27TER_EQUALIZER_LEN.

int v27ter_rx_fillin ( v27ter_rx_state_t s,
int  len 
)

Fake processing of a missing block of received V.27ter modem audio samples.

Fake processing of a missing block of received V.27ter 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 v27ter_rx_free ( v27ter_rx_state_t s  ) 

Free a V.27ter modem receive context.

Free a V.27ter modem receive context.

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

logging_state_t* v27ter_rx_get_logging_state ( v27ter_rx_state_t s  ) 

Get the logging context associated with a V.27ter modem receive context.

Get the logging context associated with a V.27ter modem receive context.

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

v27ter_rx_state_t* v27ter_rx_init ( v27ter_rx_state_t s,
int  bit_rate,
put_bit_func_t  put_bit,
void *  user_data 
)

Initialise a V.27ter modem receive context.

Initialise a V.27ter modem receive context.

Parameters:
s The modem context.
bit_rate The bit rate of the modem. Valid values are 2400 and 4800.
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 v27ter_rx_restart(), and v27ter_rx_signal_cutoff().

int v27ter_rx_release ( v27ter_rx_state_t s  ) 

Release a V.27ter modem receive context.

Release a V.27ter modem receive context.

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

int v27ter_rx_restart ( v27ter_rx_state_t s,
int  bit_rate,
int  old_train 
)

Reinitialise an existing V.27ter modem receive context.

Reinitialise an existing V.27ter modem receive context.

Parameters:
s The modem context.
bit_rate The bit rate of the modem. Valid values are 2400 and 4800.
old_train TRUE if a previous trained values are to be reused.
Returns:
0 for OK, -1 for bad parameter

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

Referenced by v27ter_rx(), and v27ter_rx_init().

void v27ter_rx_set_modem_status_handler ( v27ter_rx_state_t s,
modem_rx_status_func_t  handler,
void *  user_data 
)

Change the modem status report function associated with a V.27ter modem receive context.

Change the modem status report function associated with a V.27ter modem receive context.

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

void v27ter_rx_set_put_bit ( v27ter_rx_state_t s,
put_bit_func_t  put_bit,
void *  user_data 
)

Change the put_bit function associated with a V.27ter modem receive context.

Change the put_bit function associated with a V.27ter modem receive context.

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

void v27ter_rx_set_qam_report_handler ( v27ter_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 v27ter_rx_signal_cutoff ( v27ter_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 v27ter_rx_init().

float v27ter_rx_signal_power ( v27ter_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 v27ter_rx_symbol_timing_correction ( v27ter_rx_state_t s  ) 

Get the current symbol timing correction since startup.

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


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