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NXDN48 Voice Decoding is Good Now

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NXDN48 Voice Decoding is Good Now

Just use squelch if using SDR++ or GQRX to feed it. RTL-SDR input mode and NXDN still makes tons of false positives, and doesn't work well at all. May just be a bad signal issue but still think the RTLSDR input uses wrong center freq/tuned freq/"optimizations", need to get back to that some time, maybe also implement squelch settings on rtl_fm mode.

Thanks to LouisErigHerve for his 'Improved NXDN Detection' update on his version, implemented it and works SO MUCH BETTER!

May still disable the if ((state->lastsynctype == 9) || (state->lastsynctype == 17)) condition in dsd_frame_sync.c if I think it leads to more consistent decoding vs false positives. USE SQUELCH!
This commit is contained in:
lwvmobile
2022-01-31 23:54:14 -05:00
committed by GitHub
parent 93ccc668d7
commit 1e95db0977
4 changed files with 134 additions and 36 deletions
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61
src/dsd_frame_sync.c
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@@ -19,6 +19,39 @@
#include <locale.h>
#include <ncurses.h>
//borrowed from LEH for 'improved NXDN sync detection'
int strncmperr(const char *s1, const char *s2, size_t size, int MaxErr)
{
int Compare = -1;
size_t i = 0;
int err = 0;
int BreakBeforeEnd = 0;
if(s1 && s2)
{
for(i = 0; i < size; i++)
{
if(((s1[i] & 0xFF) != '\0') && ((s2[i] & 0xFF) != '\0'))
{
if((s1[i] & 0xFF) != (s2[i] & 0xFF)) err++;
}
else
{
BreakBeforeEnd = 1;
break;
}
}
if((err <= MaxErr) && (BreakBeforeEnd == 0))
{
Compare = 0;
}
} /* End if(s1 && s2) */
return Compare;
} /* End strncmperr() */
//end LEH
time_t now;
char * getTime(void) //get pretty hh:mm:ss timestamp
{
@@ -64,8 +97,10 @@ printFrameSync (dsd_opts * opts, dsd_state * state, char *frametype, int offset,
//strftime (datestr, 31, "%Y-%m-%d-%H%M%S", &timep);
//printf ("Sync: %s ", frametype);
//printf ("%s %s Sync: %s ", getDate(), getTime(), frametype);
printf ("%s Sync: %s ", getTime(), frametype);
printw("%s Sync: %s ", getTime(), frametype);
printf ("%s ", getTime());
printf ("Sync: %s ", frametype);
//printf("%s Sync: %s ", getTime(), frametype);
//printw("%s Sync: %s ", getTime(), frametype);
}
if (opts->verbose > 2)
{
@@ -562,12 +597,16 @@ getFrameSync (dsd_opts * opts, dsd_state * state)
}
}
if ((opts->frame_nxdn96 == 1) || (opts->frame_nxdn48 == 1))
{
strncpy (synctest18, (synctest_p - 17), 18);
if ((strcmp (synctest18, NXDN_BS_VOICE_SYNC) == 0) || (strcmp (synctest18, NXDN_MS_VOICE_SYNC) == 0))
strncpy (synctest18, (synctest_p - 17), 18); //seems like other sync tests do this as well
//if ((strcmp (synctest18, NXDN_BS_VOICE_SYNC) == 0) || (strcmp (synctest18, NXDN_MS_VOICE_SYNC) == 0)) //or is this the double up test?
//borrowing from LEH here WOW! This works so much better, its not even a joke
if ((strncmperr (synctest18, NXDN_BS_VOICE_SYNC, 18, 1) == 0) || (strncmperr (synctest18, NXDN_MS_VOICE_SYNC, 18, 1) == 0))
{
if ((state->lastsynctype == 8) || (state->lastsynctype == 16))
if ((state->lastsynctype == 8) || (state->lastsynctype == 16)) //is this checking for multiple matches first, could be causing 'skips' in audio decode HERE HERE
//if ( (opts->frame_nxdn96 == 1) ||(opts->frame_nxdn48 == 1)) //kind of hacky, but too lazy to remove brackets and re-indent
{
state->carrier = 1;
state->offset = synctest_pos;
@@ -597,9 +636,11 @@ getFrameSync (dsd_opts * opts, dsd_state * state)
state->lastsynctype = 8;
}
}
else if ((strcmp (synctest18, INV_NXDN_BS_VOICE_SYNC) == 0) || (strcmp (synctest18, INV_NXDN_MS_VOICE_SYNC) == 0))
//else if ((strcmp (synctest18, INV_NXDN_BS_VOICE_SYNC) == 0) || (strcmp (synctest18, INV_NXDN_MS_VOICE_SYNC) == 0))
else if ((strncmperr (synctest18, NXDN_BS_DATA_SYNC, 18, 1) == 0) || (strncmperr (synctest18, NXDN_MS_DATA_SYNC, 18, 1) == 0))
{
if ((state->lastsynctype == 9) || (state->lastsynctype == 17))
//if ( (opts->frame_nxdn96 == 1) ||(opts->frame_nxdn48 == 1)) //again, skip the double up
{
state->carrier = 1;
state->offset = synctest_pos;
@@ -629,9 +670,11 @@ getFrameSync (dsd_opts * opts, dsd_state * state)
state->lastsynctype = 9;
}
}
else if ((strcmp (synctest18, NXDN_BS_DATA_SYNC) == 0) || (strcmp (synctest18, NXDN_MS_DATA_SYNC) == 0))
//else if ((strcmp (synctest18, NXDN_BS_DATA_SYNC) == 0) || (strcmp (synctest18, NXDN_MS_DATA_SYNC) == 0))
else if ((strncmperr (synctest18, NXDN_BS_DATA_SYNC, 18, 1) == 0) || (strncmperr (synctest18, NXDN_MS_DATA_SYNC, 18, 1) == 0))
{
if ((state->lastsynctype == 8) || (state->lastsynctype == 16))
//if ( (opts->frame_nxdn96 == 1) ||(opts->frame_nxdn48 == 1))
{
state->carrier = 1;
state->offset = synctest_pos;
@@ -661,9 +704,11 @@ getFrameSync (dsd_opts * opts, dsd_state * state)
state->lastsynctype = 16;
}
}
else if ((strcmp (synctest18, INV_NXDN_BS_DATA_SYNC) == 0) || (strcmp (synctest18, INV_NXDN_MS_DATA_SYNC) == 0))
//else if ((strcmp (synctest18, INV_NXDN_BS_DATA_SYNC) == 0) || (strcmp (synctest18, INV_NXDN_MS_DATA_SYNC) == 0))
else if ((strncmperr (synctest18, INV_NXDN_BS_DATA_SYNC, 18, 1) == 0) || (strncmperr (synctest18, INV_NXDN_MS_DATA_SYNC, 18, 1) == 0))
{
if ((state->lastsynctype == 9) || (state->lastsynctype == 17))
//if ( (opts->frame_nxdn96 == 1) ||(opts->frame_nxdn48 == 1))
{
state->carrier = 1;
state->offset = synctest_pos;