spandsp 0.0.6
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.
int 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.
int 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.
int 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.
int tone_on_check_time
 The tone on persistence check, in audio samples.
int tone_off_check_time
 The tone off persistence check, in audio samples.
int tones
 The number of tones used.
const sig_tone_notch_coeffs_tnotch [2]
 The coefficients for the cascaded bi-quads notch filter.
const sig_tone_flat_coeffs_tflat
 The coefficients for the single bi-quad flat mode filter.
int16_t detection_ratio
 Minimum signalling tone to total power ratio, in dB.
int16_t sharp_detection_threshold
 Minimum total power for detection in sharp mode, in dB.
int16_t 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.


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