sig_tone_descriptor_t Struct Reference

#include <sig_tone.h>

Public Attributes
int	tone_freq [2]
	The tones used.
int	tone_amp [2][2]
	The high and low tone amplitudes for each of the tones, in dBm0.
span_sample_timer_t	high_low_timeout
	The delay, in audio samples, before the high level tone drops to a low level tone. Some signalling protocols require the signalling tone be started at a high level, to ensure crisp initial detection at the receiver, but require the tone amplitude to drop by a number of dBs if it is sustained, to reduce crosstalk levels.
span_sample_timer_t	sharp_flat_timeout
	Some signalling tone detectors use a sharp initial filter, changing to a broader, flatter, filter after some delay. This parameter defines the delay. 0 means it never changes.
span_sample_timer_t	notch_lag_time
	Parameters to control the behaviour of the notch filter, used to remove the tone from the voice path in some protocols. The notch is applied as fast as possible, when the signalling tone is detected. Its removal is delayed by this timeout, to avoid clicky noises from repeated switching of the filter on rapid pulses of signalling tone.
span_sample_timer_t	tone_on_check_time
	The tone on persistence check, in audio samples.
span_sample_timer_t	tone_off_check_time
	The tone off persistence check, in audio samples.
int	tones
	The number of tones used.
const sig_tone_notch_coeffs_t *	notch [2]
	The coefficients for the cascaded bi-quads notch filter.
const sig_tone_flat_coeffs_t *	flat
	The coefficients for the single bi-quad flat mode filter.
float	detection_ratio
	Minimum signalling tone to total power ratio, in dB.
float	sharp_detection_threshold
	Minimum total power for detection in sharp mode, in dB.
float	flat_detection_threshold
	Minimum total power for detection in flat mode, in dB.

Detailed Description

signalling tone descriptor. This defines the working state for a single instance of the transmit and receive sides of a signalling tone processor.

Member Data Documentation

detection_ratio

float sig_tone_descriptor_t::detection_ratio

Minimum signalling tone to total power ratio, in dB.

Referenced by sig_tone_rx_init().

flat

const sig_tone_flat_coeffs_t* sig_tone_descriptor_t::flat

The coefficients for the single bi-quad flat mode filter.

Referenced by sig_tone_rx().

flat_detection_threshold

float sig_tone_descriptor_t::flat_detection_threshold

Minimum total power for detection in flat mode, in dB.

Referenced by sig_tone_rx_init().

high_low_timeout

span_sample_timer_t sig_tone_descriptor_t::high_low_timeout

The delay, in audio samples, before the high level tone drops to a low level tone. Some signalling protocols require the signalling tone be started at a high level, to ensure crisp initial detection at the receiver, but require the tone amplitude to drop by a number of dBs if it is sustained, to reduce crosstalk levels.

Referenced by sig_tone_tx_set_mode().

notch

const sig_tone_notch_coeffs_t* sig_tone_descriptor_t::notch[2]

The coefficients for the cascaded bi-quads notch filter.

Referenced by sig_tone_rx().

notch_lag_time

span_sample_timer_t sig_tone_descriptor_t::notch_lag_time

Parameters to control the behaviour of the notch filter, used to remove the tone from the voice path in some protocols. The notch is applied as fast as possible, when the signalling tone is detected. Its removal is delayed by this timeout, to avoid clicky noises from repeated switching of the filter on rapid pulses of signalling tone.

Referenced by sig_tone_rx().

sharp_detection_threshold

float sig_tone_descriptor_t::sharp_detection_threshold

Minimum total power for detection in sharp mode, in dB.

Referenced by sig_tone_rx_init().

sharp_flat_timeout

span_sample_timer_t sig_tone_descriptor_t::sharp_flat_timeout

Some signalling tone detectors use a sharp initial filter, changing to a broader, flatter, filter after some delay. This parameter defines the delay. 0 means it never changes.

Referenced by sig_tone_rx().

tone_amp

int sig_tone_descriptor_t::tone_amp[2][2]

The high and low tone amplitudes for each of the tones, in dBm0.

Referenced by sig_tone_tx_init().

tone_freq

int sig_tone_descriptor_t::tone_freq[2]

The tones used.

Referenced by sig_tone_tx_init().

tone_off_check_time

span_sample_timer_t sig_tone_descriptor_t::tone_off_check_time

The tone off persistence check, in audio samples.

Referenced by sig_tone_rx().

tone_on_check_time

span_sample_timer_t sig_tone_descriptor_t::tone_on_check_time

The tone on persistence check, in audio samples.

Referenced by sig_tone_rx().

tones

int sig_tone_descriptor_t::tones

The number of tones used.

Referenced by sig_tone_rx(), and sig_tone_tx().

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The documentation for this struct was generated from the following file:

• private/sig_tone.h