ilec.h

The line echo canceller (LEC) is designed to provide the maximum attainable transparent voice qualit

/*------------------------------------------------------------------------*
*                                                                         *
*   THIS IS AN UNPUBLISHED WORK CONTAINING CONFIDENTIAL AND PROPRIETARY   *
*   INFORMATION.  IF PUBLICATION OCCURS, THE FOLLOWING NOTICE APPLIES:    *
*      "COPYRIGHT 2001 MIKET DSP SOLUTIONS, ALL RIGHTS RESERVED"          *
*                                                                         *
*-------------------------------------------------------------------------*/ 
#ifndef ILEC_
#define ILEC_    

#include <std.h>
#include <ialg.h>

/*--------------------- public defs ---------------------------------------*/ 

#define ILEC_FR_SZ          (40)
#define ILEC_FR_MS          (5)

typedef struct ILEC_Obj {
    struct ILEC_Fxns *fxns;
} ILEC_Obj;

typedef struct ILEC_Obj *ILEC_Handle;



/*
 *  ------- control interface ---------
 *
 * use it while calling algControl()
 */                          

/*  definition of Cmd param of LEC_control(), to be or'ed      */
#define ILEC_CMD_OFF_MASK           (0x0001)
#define ILEC_CMD_RESET_MASK         (0x0002)
#define ILEC_CMD_DETECT_HITX_MASK   (0x0004)
#define ILEC_CMD_NOADAPT_MASK       (0x0008)
#define ILEC_CMD_TONE_ECHO_MASK     (0x0010)
#define ILEC_CMD_PRESERVE_FLT_MASK  (0x0020)
#define ILEC_CMD_LOOPBACK_MASK      (0x0040)
#define ILEC_CMD_HIPASS_MASK        (0x0080)
#define ILEC_CMD_NLP_OFF_MASK       (0x0100)
#define ILEC_CMD_CLR_HITX_DT_MASK   (0x0200)

/* Configuration of LEC */
/*  All relevant parameters are expressed in dB, scaled up with a coeff,
    so that
    
        1 dB corresponds to 512/3.0103 ~ 170.083 ~ 170 

    The scaling was chosen as a compromise:
        - to make log scale computation fast and simple;
        - to allow enough breathing space to run averaging;
        - leave some headroom for data manipulation;
        - allow non-integer values;
        - 0 corresponds to 0dBm signal (averaged over 40 samples), 
            mu-law data (8159*4 max);
        - negative values for attenuated signal;
        - min value corresponds to approx. -82.5 dBm;
        - precision is about 0.25 dB. */
#define ILEC_1DB     (170)

/*  
    While setting configuration is left to discretion of the
    user, it is recommended to be aware of the consequences.

    The run-time configuration fields include:
    
    */
typedef struct ILEC_tCfg {
    Int uControl;
    Int sErlMin;
    Int sTxMax;
    Int sClipThr;
    Int sToneDetectThr;
    Int sToneReleaseThr;
} ILEC_tCfg;

/*
 *  ======== ILEC_Params ========
 *  This structure defines the parameters necessary to create an
 *  instance of a MF object.
 *
 */                 
 

typedef struct ILEC_Params {
    Int size;           /* sizeof the whole parameter struct */
    ILEC_tCfg *pCfg;
} ILEC_Params;


typedef struct ILEC_Status {
    Int size;           /* sizeof the whole parameter struct */
    ILEC_tCfg *pCfg;   /* in: ptr to cfg to update. used if and only if CMD_CFG indicated */
} ILEC_Status;



/*
 *  ======== ILEC_Fxns ========
 *  By convention the name of the variable is LEC_MIKET_ILEC, where
 *  MIKET is the vendor name.
 */
typedef struct ILEC_Fxns {
    IALG_Fxns   ialg;
    /* functions returns report word described above */
    Int         (*algProcess)(IALG_Handle handle, Int *pRcv, Int *pSnd);
} ILEC_Fxns;

/*--------------------- local defs ----------------------------------------*/ 
/*--------------------- public vars ---------------------------------------*/
/*--------------------- local vars ----------------------------------------*/
/*--------------------- local functions -----------------------------------*/
/*--------------------- public  functions ---------------------------------*/

#endif  /* ILEC_ */