libspandsp 0.0.4

modem_connect_tones.h File Reference

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Classes

struct  modem_connect_tones_tx_state_t
struct  modem_connect_tones_rx_state_t

Enumerations

enum  {
  MODEM_CONNECT_TONES_NONE = 0, MODEM_CONNECT_TONES_FAX_CNG = 1, MODEM_CONNECT_TONES_FAX_CED = 2, MODEM_CONNECT_TONES_ANS = 3,
  MODEM_CONNECT_TONES_ANS_PR = 4, MODEM_CONNECT_TONES_ANSAM = 5, MODEM_CONNECT_TONES_ANSAM_PR = 6, MODEM_CONNECT_TONES_FAX_PREAMBLE = 7
}

Functions

modem_connect_tones_tx_state_tmodem_connect_tones_tx_init (modem_connect_tones_tx_state_t *s, int tone_type)
 Initialise an instance of the modem connect tones generator.
int modem_connect_tones_tx_free (modem_connect_tones_tx_state_t *s)
 Free an instance of the modem connect tones generator.
int modem_connect_tones_tx (modem_connect_tones_tx_state_t *s, int16_t amp[], int len)
 Generate a block of modem connect tones samples.
int modem_connect_tones_rx (modem_connect_tones_rx_state_t *s, const int16_t amp[], int len)
 Process a block of samples through an instance of the modem connect tones detector.
int modem_connect_tones_rx_get (modem_connect_tones_rx_state_t *s)
 Test if a modem_connect tone has been detected.
modem_connect_tones_rx_state_tmodem_connect_tones_rx_init (modem_connect_tones_rx_state_t *s, int tone_type, tone_report_func_t tone_callback, void *user_data)
 Initialise an instance of the modem connect tones detector.
int modem_connect_tones_rx_free (modem_connect_tones_rx_state_t *s)
 Free an instance of the modem connect tones detector.

Detailed Description


Enumeration Type Documentation

anonymous enum
Enumerator:
MODEM_CONNECT_TONES_FAX_CNG 

CNG tone is a pure 1100Hz tone, in 0.5s bursts, with 3s silences in between. The bursts repeat for as long as is required.

MODEM_CONNECT_TONES_FAX_CED 

CED tone is a pure continuous 2100Hz+-15Hz tone for 3.3s+-0.7s. We might see FAX preamble instead of CED, of the FAX machine does not answer with CED.

MODEM_CONNECT_TONES_ANS 

ANS tone is a pure continuous 2100Hz+-15Hz tone for 3.3s+-0.7s. Nothing else is searched for.

MODEM_CONNECT_TONES_ANS_PR 

ANS with phase reversals tone is a 2100Hz+-15Hz tone for 3.3s+-0.7s, with a 180 degree phase jump every 450ms+-25ms.

MODEM_CONNECT_TONES_ANSAM 

The ANSam tone is a version of ANS with 20% of 15Hz+-0.1Hz AM modulation, as per V.8.

MODEM_CONNECT_TONES_ANSAM_PR 

The ANSam with phase reversals tone is a version of ANS_PR with 20% of 15Hz+-0.1Hz AM modulation, as per V.8.

MODEM_CONNECT_TONES_FAX_PREAMBLE 

FAX preamble in a string of V.21 HDLC flag octets. This is only valid as a result of tone detection. It should not be specified as a tone type to transmit or receive.


Function Documentation

int modem_connect_tones_rx_free ( modem_connect_tones_rx_state_t s)

Free an instance of the modem connect tones detector.

Parameters:
sThe context.
Returns:
0 for OK, else -1.
int modem_connect_tones_rx_get ( modem_connect_tones_rx_state_t s)

Test if a modem_connect tone has been detected.

Parameters:
sThe context.
Returns:
TRUE if tone is detected, else FALSE.

References modem_connect_tones_rx_state_t::hit.

Referenced by v8_rx().

int modem_connect_tones_tx ( modem_connect_tones_tx_state_t s,
int16_t  amp[],
int  len 
)

Generate a block of modem connect tones samples.

Parameters:
sThe context.
ampAn array of signal samples.
lenThe number of samples to generate.
Returns:
The number of samples generated.

References dds_mod(), modem_connect_tones_tx_state_t::duration_timer, modem_connect_tones_tx_state_t::hop_timer, MODEM_CONNECT_TONES_ANS, MODEM_CONNECT_TONES_ANS_PR, MODEM_CONNECT_TONES_ANSAM, MODEM_CONNECT_TONES_ANSAM_PR, MODEM_CONNECT_TONES_FAX_CED, and MODEM_CONNECT_TONES_FAX_CNG.

Referenced by v8_tx().

int modem_connect_tones_tx_free ( modem_connect_tones_tx_state_t s)

Free an instance of the modem connect tones generator.

Parameters:
sThe context.
Returns:
0 for OK, else -1.