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Merged revisions 80820 via svnmerge from 

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
r80820 | russell | 2007-08-24 15:24:05 -0500 (Fri, 24 Aug 2007) | 7 lines

Improve the debouncing logic in the DTMF detector to fix some reliability
issues.  Previously, this code used a shift register of hits and non-hits.
However, if the start of the digit isn't clean, it is possible for the
leading edge detector to miss the digit.  These changes replace the flawed
shift register logic and also does the debouncing on the trailing edge as well.
(closes issue #10535, many thanks to softins for the patch)

........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@80821 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Russell Bryant 2007-08-24 20:25:39 +00:00
parent eb0e0ec33f
commit 7ddccc897f
1 changed files with 33 additions and 19 deletions
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52
main/dsp.c
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@ -218,7 +218,7 @@ typedef struct
int hit3;
int hit4;
#else
int hits[3];
int lasthit;
#endif
int mhit;
float energy;
@ -383,7 +383,7 @@ static void ast_dtmf_detect_init (dtmf_detect_state_t *s)
s->hit4 =
s->hit2 = 0;
#else
s->hits[0] = s->hits[1] = s->hits[2] = 0;
s->lasthit = 0;
#endif
for (i = 0; i < 4; i++) {
goertzel_init (&s->row_out[i], dtmf_row[i], 102);
@ -588,6 +588,7 @@ static int dtmf_detect (dtmf_detect_state_t *s, int16_t amp[], int samples,
amp[i] = 0;
*writeback = 1;
}
#ifdef OLD_DSP_ROUTINES
/* Look for two successive similar results */
/* The logic in the next test is:
We need two successive identical clean detects, with
@ -595,7 +596,6 @@ static int dtmf_detect (dtmf_detect_state_t *s, int16_t amp[], int samples,
back to back differing digits. More importantly, it
can work with nasty phones that give a very wobbly start
to a digit */
#ifdef OLD_DSP_ROUTINES
if (hit == s->hit3 && s->hit3 != s->hit2) {
s->mhit = hit;
s->digit_hits[(best_row << 2) + best_col]++;
@ -607,21 +607,33 @@ static int dtmf_detect (dtmf_detect_state_t *s, int16_t amp[], int samples,
s->lost_digits++;
}
}
#else
if (hit == s->hits[2] && hit != s->hits[1] && hit != s->hits[0]) {
s->mhit = hit;
s->digit_hits[(best_row << 2) + best_col]++;
s->detected_digits++;
if (s->current_digits < MAX_DTMF_DIGITS) {
s->digits[s->current_digits++] = hit;
s->digits[s->current_digits] = '\0';
} else {
s->lost_digits++;
}
}
#endif
}
}
#ifndef OLD_DSP_ROUTINES
/* Look for two successive similar results */
/* The logic in the next test is:
We need two successive identical clean detects, with
something different preceeding it. This can work with
back to back differing digits. More importantly, it
can work with nasty phones that give a very wobbly start
to a digit */
if (hit == s->lasthit && hit != s->mhit) {
if (hit) {
s->digit_hits[(best_row << 2) + best_col]++;
s->detected_digits++;
if (s->current_digits < MAX_DTMF_DIGITS) {
s->digits[s->current_digits++] = hit;
s->digits[s->current_digits] = '\0';
} else {
s->lost_digits++;
}
}
s->mhit = hit;
}
#endif
#ifdef FAX_DETECT
if (!hit && (fax_energy >= FAX_THRESHOLD) &&
(fax_energy >= DTMF_TO_TOTAL_ENERGY*s->energy) &&
@ -652,9 +664,7 @@ static int dtmf_detect (dtmf_detect_state_t *s, int16_t amp[], int samples,
s->hit2 = s->hit3;
s->hit3 = hit;
#else
s->hits[0] = s->hits[1];
s->hits[1] = s->hits[2];
s->hits[2] = hit;
s->lasthit = hit;
#endif
/* Reinitialise the detector for the next block */
for (i = 0; i < 4; i++) {
@ -674,11 +684,15 @@ static int dtmf_detect (dtmf_detect_state_t *s, int16_t amp[], int samples,
s->energy = 0.0;
s->current_sample = 0;
}
#ifdef OLD_DSP_ROUTINES
if ((!s->mhit) || (s->mhit != hit)) {
s->mhit = 0;
return(0);
}
return (hit);
#else
return (s->mhit); /* return the debounced hit */
#endif
}
/* MF goertzel size */
@ -1690,7 +1704,7 @@ void ast_dsp_digitreset(struct ast_dsp *dsp)
#endif
dsp->td.dtmf.hit1 = dsp->td.dtmf.hit2 = dsp->td.dtmf.hit3 = dsp->td.dtmf.hit4 = dsp->td.dtmf.mhit = 0;
#else
dsp->td.dtmf.hits[2] = dsp->td.dtmf.hits[1] = dsp->td.dtmf.hits[0] = dsp->td.dtmf.mhit = 0;
dsp->td.dtmf.lasthit = dsp->td.dtmf.mhit = 0;
#endif
dsp->td.dtmf.energy = 0.0;
dsp->td.dtmf.current_sample = 0;