www.pudn.com > SMV_Code.rar > dtmf20ms.c
/*=========================================================================*/
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/*=========================================================================*/
/* */
/*-------------------------------------------------------------------*/
/*===================================================================*/
/*===========================================================================*/
/* ..Includes. */
/*---------------------------------------------------------------------------*/
#include
#include "agc.h"
#include "check.h"
#include "dtmf_det.h"
#include "dtmf.h"
#include "goertzel.h"
#include "tables.h"
/*===========================================================================*/
/* ..Defines. */
/*---------------------------------------------------------------------------*/
/*===========================================================================*/
/* ..Globals. */
/*---------------------------------------------------------------------------*/
/*===========================================================================*/
/* ..EVRC 20ms DTMF Detector Task (called every 160 samples) */
/*---------------------------------------------------------------------------*/
/* buffer[] (simulates EVRC data buffering)
*
* new data read in from file
* (new_dataP) (160 points)
* |--------------------------------|
* |<------A------->|<------B------>|<------C------->|
* |----------------|--------------------------------|----------------|
* lookback data to be processed by vocoder lookahead
* (80 points) (cur_dataP) (160 points) (80 points)
*
*
* Muting Logic:
* -------------
* if (block B AND block C contain "possible DTMF"),
* then mute blocks A and B;
* if ( (DtmfDetectStatLast == 1) // Valid DTMF tone in last DTMF block?
* AND (80pt DTMF block A contains "possible DTMF") ),
* then mute blocks A, B, and C;
*/
short Dtmf20ms (
DTMF_DETECTOR* D, /* (i) - pointer to detector structure */
short* buffer, /* (i) - EVRC data buffer (see comments above) */
short* digit /* (i) - DTMF digit or -1 if no DTMF detect*/
)
{
/*....(static) variables....*/
static long dtmfblock10ms = 0; /* 10ms DTMF block counter */
/* (Not needed in DSP implementation!!) */
/*....(local) variables....*/
register int j;
short DtmfDetectStatLast;
short digit1,digit2;
short possible_tone_block_A;
short possible_tone_block_B;
short possible_tone_block_C;
short* dataP;
short* cur_dataP;
short* new_dataP;
short dtmf_buf[N];
short mute = 0; /* =1 mute current 160, =2 mute current+
look_ahead */
/*....execute....*/
dataP = &buffer[0]; /* start of look-back */
cur_dataP = &buffer[80]; /* current 160pt frame to be processed */
new_dataP = &buffer[160]; /* start of data read in from file */
possible_tone_block_A = D->PossibleDtmfLast;
/* Move data to local buffer since DtmfDetector() overwrites data...*/
for (j=0; jDtmfDetectStat;
digit1= -1;
if (D->DtmfDetectStat ==1 )
digit1 = D->DtmfDigit;
dtmfblock10ms++;
/* Process second N samples (lookahead) */
for (j=0; jDtmfDetectStat ==1 )
digit2 =D->DtmfDigit;
dtmfblock10ms++;
/* Decide whether or not to mute */
if ( possible_tone_block_B && possible_tone_block_C )
{
mute=1;
for (j=0; j<160; j++) {
cur_dataP[j] = 0;
}
}
if ( (possible_tone_block_A) && (DtmfDetectStatLast == 1) )
{
mute=2;
for (j=0; j<240; j++) {
cur_dataP[j] = 0;
}
}
D->PossibleDtmfLast = possible_tone_block_C;
*digit = -1;
if (digit1> -1 ) *digit=digit1;
if (digit2> -1 ) *digit=digit2;
return mute;
}