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/*
Important constants for tuning kb1 echo can
*/
#ifndef _MEC2_CONST_H
#define _MEC2_CONST_H
/* Convergence (aka. adaptation) speed -- higher means slower */
#define DEFAULT_BETA1_I 2048
/* Constants for various power computations */
#define DEFAULT_SIGMA_LY_I 7
#define DEFAULT_SIGMA_LU_I 7
#define DEFAULT_ALPHA_ST_I 5 /* near-end speech detection sensitivity factor */
#define DEFAULT_ALPHA_YT_I 5
#define DEFAULT_CUTOFF_I 128
/* Define the near-end speech hangover counter: if near-end speech
* is declared, hcntr is set equal to hangt (see pg. 432)
*/
#define DEFAULT_HANGT 600 /* in samples, so 600 samples = 75ms */
/* define the residual error suppression threshold */
#define DEFAULT_SUPPR_I 16 /* 16 = -24db */
/* This is the minimum reference signal power estimate level
* that will result in filter adaptation.
* If this is too low then background noise will cause the filter
* coefficients to constantly be updated.
*/
#define MIN_UPDATE_THRESH_I 4096
/* The number of samples used to update coefficients using the
* the block update method (M). It should be related back to the
* length of the echo can.
* ie. it only updates coefficients when (sample number MOD default_m) = 0
*
* Getting this wrong may cause an oops. Consider yourself warned!
*/
#define DEFAULT_M 16 /* every 16th sample */
/* If AGGRESSIVE supression is enabled, then we start cancelling residual
* echos again even while there is potentially the very end of a near-side
* signal present.
* This defines how many samples of DEFAULT_HANGT can remain before we
* kick back in
*/
#define AGGRESSIVE_HCNTR 160 /* in samples, so 160 samples = 20ms */
/* This knob controls the number of passes the residual echo supression
* algorithm makes.
*/
#ifdef AGGRESSIVE_SUPPRESSOR
#define RESIDUAL_SUPRESSION_PASSES 2
#else
#define RESIDUAL_SUPRESSION_PASSES 1
#endif
/* If defined then agressive echo cancellation will only be used for
* this amount of time then we will go back to normal cancelation.
* This is helpful if you have bad echo while training
*/
/* #define AGGRESSIVE_TIMELIMIT 150000 */ /* 8 = 1ms */
/***************************************************************/
/* The following knobs are not implemented in the current code */
/* we need a dynamic level of suppression varying with the ratio of the
power of the echo to the power of the reference signal this is
done so that we have a smoother background.
we have a higher suppression when the power ratio is closer to
suppr_ceil and reduces logarithmically as we approach suppr_floor.
*/
#define SUPPR_FLOOR -64
#define SUPPR_CEIL -24
/* in a second departure, we calculate the residual error suppression
* as a percentage of the reference signal energy level. The threshold
* is defined in terms of dB below the reference signal.
*/
#define RES_SUPR_FACTOR -20
#endif /* _MEC2_CONST_H */
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