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minimodem trick detect

This commit is contained in:
Kamal Mostafa 2011-05-25 16:41:57 -07:00
parent 62dbd2c27c
commit 4aa97884c4
1 changed files with 11 additions and 14 deletions
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25
src/minimodem.c
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@ -237,26 +237,21 @@ reprocess_audio:
float msdelta = mag_mark - mag_space; float msdelta = mag_mark - mag_space;
#define TRICK_DETECT ( 0.5 * MAX(mag_mark,mag_space) )
// Detect carrier // Detect carrier
float mag_detect = 0.01; float mag_detect = 0.001;
unsigned char carrier_detect = mag_mark + mag_space > mag_detect unsigned char carrier_detect =
? 1 : 0; mag_mark + mag_space > mag_detect
&&
fabs(msdelta) >= TRICK_DETECT;
#ifdef TRICK #ifdef TRICK
// #define TRICK_DETECT 0.0
// #define TRICK_DETECT 0.4
// #define TRICK_DETECT 0.1
// #define TRICK_DETECT mag_detect
#define TRICK_DETECT ( 0.1 * (float)decode_rate/300 )
// EXCELLENT trick -- fixes 300 baud perfectly // EXCELLENT trick -- fixes 300 baud perfectly
// shift the input window if the msdelta is small // shift the input window if the msdelta is small
static unsigned int skipped_frames = 0; static unsigned int skipped_frames = 0;
if ( carrier_detected && fabs(msdelta) < TRICK_DETECT ) if ( carrier_detected && fabs(msdelta) < TRICK_DETECT )
{ {
# if 0 # if 0
skipped_frames++; skipped_frames++;
@ -303,7 +298,8 @@ reprocess_audio:
unsigned char bit; unsigned char bit;
if ( carrier_detect ) { if ( carrier_detect )
{
bit = signbit(msdelta) ? 0 : 1; bit = signbit(msdelta) ? 0 : 1;
#if 0 #if 0
@ -329,7 +325,8 @@ reprocess_audio:
// 1dddddddd01 // 1dddddddd01
bfsk_bits = (bfsk_bits>>1) | (bit << 10); bfsk_bits = (bfsk_bits>>1) | (bit << 10);
if ( ! carrier_detect ) { if ( ! carrier_detect )
{
if ( carrier_detected ) { if ( carrier_detected ) {
printf( "###NOCARRIER###\n"); printf( "###NOCARRIER###\n");
carrier_detected = 0; carrier_detected = 0;