v29rx.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 "v29tx_constellation_maps.h"
#include "v29rx_floating_rrc.h"

Defines
#define	CARRIER_NOMINAL_FREQ   1700.0f
#define	BAUD_RATE   2400
#define	EQUALIZER_DELTA   0.21f
#define	V29_TRAINING_SEG_2_LEN   128
#define	V29_TRAINING_SEG_3_LEN   384
#define	V29_TRAINING_SEG_4_LEN   48
#define	V29_EQUALIZER_LEN   (V29_EQUALIZER_PRE_LEN + 1 + V29_EQUALIZER_POST_LEN)
#define	SYNC_LOW_BAND_EDGE_COEFF_0   1.829281f
#define	SYNC_LOW_BAND_EDGE_COEFF_1   -0.980100f
#define	SYNC_HIGH_BAND_EDGE_COEFF_0   -1.285907f
#define	SYNC_HIGH_BAND_EDGE_COEFF_1   -0.980100f
#define	SYNC_CROSS_CORR_COEFF_A   -0.932131f
#define	SYNC_CROSS_CORR_COEFF_B   0.752802f
#define	SYNC_CROSS_CORR_COEFF_C   -0.378857f
Enumerations
enum	{   TRAINING_STAGE_NORMAL_OPERATION = 0, TRAINING_STAGE_SYMBOL_ACQUISITION, TRAINING_STAGE_LOG_PHASE, TRAINING_STAGE_WAIT_FOR_CDCD,   TRAINING_STAGE_TRAIN_ON_CDCD, TRAINING_STAGE_TRAIN_ON_CDCD_AND_TEST, TRAINING_STAGE_TEST_ONES, TRAINING_STAGE_PARKED }
Functions
float	v29_rx_carrier_frequency (v29_rx_state_t *s)
float	v29_rx_symbol_timing_correction (v29_rx_state_t *s)
float	v29_rx_signal_power (v29_rx_state_t *s)
void	v29_rx_signal_cutoff (v29_rx_state_t *s, float cutoff)
int	v29_rx_equalizer_state (v29_rx_state_t *s, complexf_t **coeffs)
	Get a snapshot of the current equalizer coefficients.
int	v29_rx (v29_rx_state_t *s, const int16_t amp[], int len)
	Process a block of received V.29 modem audio samples.
void	v29_rx_set_put_bit (v29_rx_state_t *s, put_bit_func_t put_bit, void *user_data)
	Change the put_bit function associated with a V.29 modem receive context.
void	v29_rx_set_modem_status_handler (v29_rx_state_t *s, modem_tx_status_func_t handler, void *user_data)
	Change the modem status report function associated with a V.29 modem receive context.
int	v29_rx_restart (v29_rx_state_t *s, int bit_rate, int old_train)
	Reinitialise an existing V.29 modem receive context.
v29_rx_state_t *	v29_rx_init (v29_rx_state_t *s, int rate, put_bit_func_t put_bit, void *user_data)
	Initialise a V.29 modem receive context.
int	v29_rx_free (v29_rx_state_t *s)
	Free a V.29 modem receive context.
void	v29_rx_set_qam_report_handler (v29_rx_state_t *s, qam_report_handler_t handler, void *user_data)

---

Detailed Description

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Function Documentation

int v29_rx	(	v29_rx_state_t *	s,
		const int16_t	amp[],
		int	len
	)

Process a block of received V.29 modem audio samples.

Process a block of received V.29 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 v29_rx_state_t::agc_scaling, v29_rx_state_t::agc_scaling_save, v29_rx_state_t::bit_rate, v29_rx_state_t::carrier_drop_pending, v29_rx_state_t::carrier_phase, v29_rx_state_t::carrier_phase_rate, dds_advance(), dds_advancef(), dds_lookup_complexf(), dds_lookup_complexi16(), v29_rx_state_t::eq_put_step, v29_rx_state_t::high_sample, complexf_t::im, v29_rx_state_t::last_sample, v29_rx_state_t::low_samples, v29_rx_state_t::power, power_meter_init(), power_meter_update(), complexf_t::re, v29_rx_state_t::rrc_filter, v29_rx_state_t::rrc_filter_step, SIG_STATUS_CARRIER_DOWN, SIG_STATUS_CARRIER_UP, v29_rx_state_t::signal_present, v29_rx_state_t::symbol_sync_high, v29_rx_state_t::symbol_sync_low, v29_rx_state_t::training_stage, v29_rx_restart(), vec_circular_dot_prodf(), and vec_circular_dot_prodi16().

float v29_rx_carrier_frequency

(

v29_rx_state_t *

s

)

Get the current received carrier frequency.

Parameters:

s

The modem context.

Returns:

The frequency, in Hertz.

References v29_rx_state_t::carrier_phase_rate, and dds_frequencyf().

int v29_rx_equalizer_state	(	v29_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 v29_rx_state_t::eq_coeff.

int v29_rx_free

(

v29_rx_state_t *

s

)

Free a V.29 modem receive context.

Free a V.29 modem receive context.

Parameters:

s

The modem context.

Returns:

0 for OK

v29_rx_state_t* v29_rx_init	(	v29_rx_state_t *	s,
		int	bit_rate,
		put_bit_func_t	put_bit,
		void *	user_data
	)

Initialise a V.29 modem receive context.

Initialise a V.29 modem receive context.

Parameters:

	s	The modem context.
	bit_rate	The bit rate of the modem. Valid values are 4800, 7200 and 9600.
	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 v29_rx_state_t::logging, v29_rx_state_t::put_bit, v29_rx_state_t::put_bit_user_data, v29_rx_restart(), and v29_rx_signal_cutoff().

int v29_rx_restart	(	v29_rx_state_t *	s,
		int	bit_rate,
		int	old_train
	)

Reinitialise an existing V.29 modem receive context.

Reinitialise an existing V.29 modem receive context.

Parameters:

	s	The modem context.
	bit_rate	The bit rate of the modem. Valid values are 4800, 7200 and 9600.
	old_train	TRUE if a previous trained values are to be reused.

Returns:

0 for OK, -1 for bad parameter

References v29_rx_state_t::agc_scaling, v29_rx_state_t::agc_scaling_save, v29_rx_state_t::baud_half, v29_rx_state_t::baud_phase, v29_rx_state_t::bit_rate, v29_rx_state_t::carrier_drop_pending, v29_rx_state_t::carrier_phase, v29_rx_state_t::carrier_phase_rate, v29_rx_state_t::carrier_phase_rate_save, v29_rx_state_t::carrier_track_i, v29_rx_state_t::carrier_track_p, v29_rx_state_t::constellation_state, dds_phase_ratef(), v29_rx_state_t::eq_skip, v29_rx_state_t::high_sample, v29_rx_state_t::last_sample, v29_rx_state_t::low_samples, v29_rx_state_t::old_train, v29_rx_state_t::power, power_meter_init(), v29_rx_state_t::rrc_filter, v29_rx_state_t::rrc_filter_step, v29_rx_state_t::scramble_reg, v29_rx_state_t::signal_present, v29_rx_state_t::symbol_sync_dc_filter, v29_rx_state_t::symbol_sync_high, v29_rx_state_t::symbol_sync_low, v29_rx_state_t::total_baud_timing_correction, v29_rx_state_t::training_cd, v29_rx_state_t::training_count, v29_rx_state_t::training_scramble_reg, and v29_rx_state_t::training_stage.

Referenced by v29_rx(), and v29_rx_init().

void v29_rx_set_modem_status_handler	(	v29_rx_state_t *	s,
		modem_rx_status_func_t	handler,
		void *	user_data
	)

Change the modem status report function associated with a V.29 modem receive context.

Change the modem status report function associated with a V.29 modem receive context.

Parameters:

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

References v29_rx_state_t::status_handler, and v29_rx_state_t::status_user_data.

void v29_rx_set_put_bit	(	v29_rx_state_t *	s,
		put_bit_func_t	put_bit,
		void *	user_data
	)

Change the put_bit function associated with a V.29 modem receive context.

Change the put_bit function associated with a V.29 modem receive context.

Parameters:

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

References v29_rx_state_t::put_bit, and v29_rx_state_t::put_bit_user_data.

void v29_rx_set_qam_report_handler	(	v29_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.

References v29_rx_state_t::qam_report, and v29_rx_state_t::qam_user_data.

void v29_rx_signal_cutoff	(	v29_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 v29_rx_state_t::carrier_off_power, v29_rx_state_t::carrier_on_power, and power_meter_level_dbm0().

Referenced by v29_rx_init().

float v29_rx_signal_power

(

v29_rx_state_t *

s

)

Get the current received signal power.

Parameters:

s

The modem context.

Returns:

The signal power, in dBm0.

References v29_rx_state_t::power, and power_meter_current_dbm0().

float v29_rx_symbol_timing_correction

(

v29_rx_state_t *

s

)

Get the current symbol timing correction since startup.

Parameters:

s

The modem context.

Returns:

The correction.

References v29_rx_state_t::total_baud_timing_correction.