v22bis_rx.c File Reference

#include <inttypes.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.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/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/v22bis.h"
#include "spandsp/private/logging.h"
#include "spandsp/private/v22bis.h"
#include "v22bis_rx_1200_floating_rrc.h"
#include "v22bis_rx_2400_floating_rrc.h"

Defines

#define ms_to_symbols(t)   (((t)*600)/1000)
#define EQUALIZER_DELTA   0.25f
#define PULSESHAPER_COEFF_SETS   12

Functions

float v22bis_rx_carrier_frequency (v22bis_state_t *s)
float v22bis_rx_symbol_timing_correction (v22bis_state_t *s)
float v22bis_rx_signal_power (v22bis_state_t *s)
void v22bis_rx_signal_cutoff (v22bis_state_t *s, float cutoff)
void v22bis_report_status_change (v22bis_state_t *s, int status)
int v22bis_rx_equalizer_state (v22bis_state_t *s, complexf_t **coeffs)
 Get a snapshot of the current equalizer coefficients.
void v22bis_equalizer_coefficient_reset (v22bis_state_t *s)
int v22bis_rx (v22bis_state_t *s, const int16_t amp[], int len)
 Process a block of received V.22bis modem audio samples.
int v22bis_rx_fillin (v22bis_state_t *s, int len)
 Fake processing of a missing block of received V.22bis modem audio samples.
int v22bis_rx_restart (v22bis_state_t *s)
 Reinitialise an existing V.22bis modem receive context.
void v22bis_rx_set_qam_report_handler (v22bis_state_t *s, qam_report_handler_t handler, void *user_data)

Detailed Description


Define Documentation

#define EQUALIZER_DELTA   0.25f

The adaption rate coefficient for the equalizer

#define PULSESHAPER_COEFF_SETS   12

The number of phase shifted coefficient set for the pulse shaping/bandpass filter

Referenced by v22bis_rx(), and v22bis_rx_symbol_timing_correction().


Function Documentation

int v22bis_rx ( v22bis_state_t s,
const int16_t  amp[],
int  len 
)

Process a block of received V.22bis modem audio samples.

Process a block of received V.22bis 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_complexf(), complexf_t::im, power_meter_update(), PULSESHAPER_COEFF_SETS, complexf_t::re, SIG_STATUS_CARRIER_DOWN, SIG_STATUS_CARRIER_UP, v22bis_restart(), and V22BIS_RX_FILTER_STEPS.

float v22bis_rx_carrier_frequency ( v22bis_state_t s  ) 

Get the current received carrier frequency.

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

References dds_frequencyf().

int v22bis_rx_equalizer_state ( v22bis_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 V22BIS_EQUALIZER_LEN.

int v22bis_rx_fillin ( v22bis_state_t s,
int  len 
)

Fake processing of a missing block of received V.22bis modem audio samples.

Fake processing of a missing block of received V.22bis 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().

int v22bis_rx_restart ( v22bis_state_t s  ) 

void v22bis_rx_set_qam_report_handler ( v22bis_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 v22bis_rx_signal_cutoff ( v22bis_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 v22bis_rx_restart().

float v22bis_rx_signal_power ( v22bis_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 v22bis_rx_symbol_timing_correction ( v22bis_state_t s  ) 

Get the current symbol timing correction since startup.

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

References PULSESHAPER_COEFF_SETS.


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