dtmfr.c

Express DSP compliant C55x DTMF detector software is proposed in two versions: one with a 5 ms frame

/*-------------------------------------------------------------------------*
*                                                                         *
*   THIS IS AN UNPUBLISHED WORK CONTAINING CONFIDENTIAL AND PROPRIETARY   *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"          *
*                                                                         *
*-------------------------------------------------------------------------*/
#include "dtmfi.h"

/*--------------------- local defs ----------------------------------------*/

/*--------------------- public vars ---------------------------------------*/

#if ! defined(_dsp)
#if (IDTMF_FR_SZ == 40)
S16 DBG_sFrameEn;
S32 DBG_slDialEn;
#endif
#include <stdlib.h>
#endif

/*--------------------- local vars ----------------------------------------*/
/*--------------------- local functions -----------------------------------*/
/*--------------------- public  functions ---------------------------------*/
/*-------------------------------------------------------------------------*/
static void 					_test
/*-------------------------------------------------------------------------*/
(
DTMF_tDb *pDb,
DTMF_tSc *pSc
)
{
    const IDTMF_tCfg *pCfg   = pDb->pCfg;
    S16 sTestFailed = 0;
    
    /* test that frame energy is high enough. */
    if (pSc->sSumEn < pCfg->sMinEnThr)
        sTestFailed |= DTMF_MASK_MIN_EN;

#if (IDTMF_FR_SZ == 40)
#if ! defined(_dsp)
        DBG_sFrameEn = pDb->v.sZFrameEn;
#endif
    /*  test that {dial + lo + hi} energies constitute 
        a major part of average of 2 frames energy. */
        if ((pDb->v.sZFrameEn - pSc->sSumDialEn) > pCfg->sSumEnThr)
            sTestFailed |= DTMF_MASK_SUM_EN;
#else
        if ((pSc->sFrameEn - pSc->sSumDialEn) > pCfg->sSumEnThr)
            sTestFailed |= DTMF_MASK_SUM_EN;
#endif

    /* test leading edge */
    {
#if (IDTMF_FR_SZ == 40)
        S16 ac0 = pDb->v.asSumEn[0];
        S16 ac1 = pDb->v.asSumEn[1];
        S16 ac2 = pDb->v.asSumEn[4];
        S16 ac3 = pDb->v.asSumEn[5];
        
        if (ac0 > ac1) ac0 = ac1; /* ac0 =  min of 2 most recent frames */
        if (ac2 < ac3) ac2 = ac3; /* ac2 =  max of 2 oldest frames */
        ac0 -= ac2;               /* energy diff */  
#else
        S16 ac0 = pDb->v.asSumEn[0];
        S16 ac1 = pDb->v.asSumEn[2];
        ac0 -= ac1;

#endif
        if (ac0 < pCfg->sNoiseThr)
            sTestFailed |= DTMF_MASK_RS_EDGE;
    }

    /* test falling edge */
    if ((pDb->v.Stat.sEn - pSc->sSumEn) < pCfg->sNoiseThr)
        sTestFailed |= DTMF_MASK_FL_EDGE;

    /* test that lo(idx) and hi(idx) energies are reasonably stable */
    if (abs(pSc->sLoMaxFreqEn - pDb->v.Stat.sLoEn) > pCfg->sVarThr)
        sTestFailed |= DTMF_MASK_STABLE;
    if (abs(pSc->sHiMaxFreqEn - pDb->v.Stat.sHiEn) > pCfg->sVarThr)
        sTestFailed |= DTMF_MASK_STABLE;

    /* test that <2k energy is significantly bigger than >2k energy */
    if (pSc->s2kEnDlt < pCfg->s2kUpThr)
        sTestFailed |= DTMF_MASK_2K_BOUND;
    
    /* test that twists are ok */
/*    if ((pSc->Hi.sMaxFreqEn - pSc->Lo.sMaxFreqEn) > pCfg->sFwdTwistThr) */
    if ((pSc->sHiBpEn-pSc->sLoBpEn) > (pCfg->sFwdTwistThr+(170+85)))
        sTestFailed |= DTMF_MASK_FWD_TWIST;
    if ((pSc->sHiBpEn-pSc->sLoBpEn) < -(pCfg->sRevTwistThr-85) )
        sTestFailed |= DTMF_MASK_REV_TWIST;

    if (pDb->v.sState < DTMF_ST_TONE)
    {
        /*  DFT delay lines are not full. at least one frame less.
            we shall account for wider sinc mainlobe and lower energy.
            Noise does not have much influence on the parameters
            in this case, so the threshold are hard coded.
            tuning criteria was chosen the number of early-on hits 
            on talk-off imunity test.
            varying those thrs shall affect early detection delay
            and talk-off immunity as well.
        */
        if ((pSc->sLoBpEn - pSc->sLoMaxFreqEn) > (6*IDTMF_1DB))
            sTestFailed |= DTMF_MASK_LO_PART;

        if ((pSc->sLoMaxFreqEn - pSc->sLoNextEn) < (5*IDTMF_1DB))
            sTestFailed |= DTMF_MASK_LO_CLEAN;

#if (IDTMF_FR_SZ == 40)

        if ((pSc->sHiBpEn - pSc->sHiMaxFreqEn) > (4*IDTMF_1DB))
            sTestFailed |= DTMF_MASK_HI_PART; 

        if ((pSc->sHiMaxFreqEn - pSc->sHiNextEn) < (7*IDTMF_1DB))
            sTestFailed |= DTMF_MASK_HI_CLEAN;
#endif
    }
    else
    {
        if ((pSc->sLoBpEn - pSc->sLoMaxFreqEn) > pCfg->sPartThr)
            sTestFailed |= DTMF_MASK_LO_PART;

        if ((pSc->sLoMaxFreqEn - pSc->sLoNextEn) < pCfg->sCleanThr)
            sTestFailed |= DTMF_MASK_LO_CLEAN;

#if (IDTMF_FR_SZ == 40)
        if ((pSc->sHiBpEn - pSc->sHiMaxFreqEn) > pCfg->sPartThr)
            sTestFailed |= DTMF_MASK_HI_PART;

        if ((pSc->sHiMaxFreqEn - pSc->sHiNextEn) < pCfg->sCleanThr)
            sTestFailed |= DTMF_MASK_HI_CLEAN;
#endif
    }
#if (IDTMF_FR_SZ == 80)
        if ((pSc->sHiBpEn - pSc->sHiMaxFreqEn) > pCfg->sPartThr)
            sTestFailed |= DTMF_MASK_HI_PART;

        if ((pSc->sHiMaxFreqEn - pSc->sHiNextEn) < pCfg->sCleanThr)
            sTestFailed |= DTMF_MASK_HI_CLEAN;
#endif

    if (abs(pSc->sLoFreqDev) > pCfg->sMaxFreqDevThr) 
        sTestFailed |= DTMF_MASK_LO_INRANGE;

    if (abs(pSc->sHiFreqDev) > pCfg->sMaxFreqDevThr) 
        sTestFailed |= DTMF_MASK_HI_INRANGE;


    pSc->sDigit = pSc->sLoFreqNo | (pSc->sHiFreqNo<<2);

    if (pDb->v.sLastDigit != pSc->sDigit)
        sTestFailed |=  DTMF_MASK_SAME_FRQ;
    
	pSc->sTestFailed = sTestFailed;
}	
/*-------------------------------------------------------------------------*/
void                    dtmf_filter_test
/*-------------------------------------------------------------------------*/
(
DTMF_tDb *pDb,
DTMF_tSc *pSc,
S16 *psIn
)
{
	dtmf_move_data_in	(pDb, pSc, psIn);
	dtmf_2k_filter		(pDb, pSc);
	dtmf_lo_filter		(pDb, pSc);
	dtmf_hi_filter		(pDb, pSc);

    pSc->sSumEn   = dtmf_en2log(pSc->slLoBpEn + pSc->slHiBpEn);
    pDb->v.asSumEn[0] = pSc->sSumEn;

	dtmf_dial_filter	(pDb, pSc);
	
	dtmf_lo_dft_main	(pDb, pSc);
	dtmf_lo_sort		(pDb, pSc);
	dtmf_lo_dft_dev		(pDb, pSc);
	dtmf_lo_freq		(pDb, pSc);

	dtmf_hi_dft_main	(pDb, pSc);
	dtmf_hi_sort		(pDb, pSc);
	dtmf_hi_dft_dev		(pDb, pSc);
	dtmf_hi_freq		(pDb, pSc);

	dtmf_frame_en 		(pDb, pSc);
	_test(pDb, pSc);
    dtmf_move_data_out  (pDb, pSc);
}

/*-------------------------------------------------------------------------*/