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_t *	v27ter_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_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.
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.