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ADD: added @marshmellow42 's changes to "lfdemod"

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iceman1001 2016-03-20 19:39:06 +01:00
commit 7fa7e812fc
2 changed files with 20 additions and 16 deletions
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34
common/lfdemod.c
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@ -261,9 +261,9 @@ void askAmp(uint8_t *BitStream, size_t size)
{
for(size_t i = 1; i<size; i++){
if (BitStream[i]-BitStream[i-1]>=30) //large jump up
BitStream[i]=127;
BitStream[i]=255;
else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
BitStream[i]=-127;
BitStream[i]=0;
}
return;
}
@ -463,10 +463,10 @@ int gProxII_Demod(uint8_t BitStream[], size_t *size)
//return start position
return (int) startIdx;
}
return -5;
return -5; //spacer bits not found - not a valid gproxII
}
//translate wave to 11111100000 (1 for each short wave 0 for each long wave)
//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
{
size_t last_transition = 0;
@ -490,6 +490,7 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
// count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
// or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
// between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
// (could also be fc/5 && fc/7 for fsk1 = 4-9)
for(idx = 161; idx < size-20; idx++) {
// threshold current value
@ -497,23 +498,24 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
else dest[idx] = 1;
// Check for 0->1 transition
if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
if (dest[idx-1] < dest[idx]) {
preLastSample = LastSample;
LastSample = currSample;
currSample = idx-last_transition;
if (currSample < (fclow-2)){ //0-5 = garbage noise (or 0-3)
//do nothing with extra garbage
} else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves or 3-6 = 5
} else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
//correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample == 0 )){
dest[numBits-1]=1; //correct previous 9 wave surrounded by 8 waves
dest[numBits-1]=1;
}
dest[numBits++]=1;
} else if (currSample > (fchigh) && !numBits) { //12 + and first bit = garbage
} else if (currSample > (fchigh) && !numBits) { //12 + and first bit = unusable garbage
//do nothing with beginning garbage
} else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's
} else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's)
dest[numBits++]=1;
} else { //9+ = 10 sample waves
} else { //9+ = 10 sample waves (or 6+ = 7)
dest[numBits++]=0;
}
last_transition = idx;
@ -523,6 +525,7 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
}
//translate 11111100000 to 10
//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
uint8_t invert, uint8_t fchigh, uint8_t fclow)
{
@ -534,6 +537,7 @@ size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
n++;
if (dest[idx]==lastval) continue;
//find out how many bits (n) we collected
//if lastval was 1, we have a 1->0 crossing
if (dest[idx-1]==1) {
n = (n * fclow + rfLen/2) / rfLen;
@ -542,6 +546,7 @@ size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
}
if (n == 0) n = 1;
//add to our destination the bits we collected
memset(dest+numBits, dest[idx-1]^invert , n);
numBits += n;
n=0;
@ -696,7 +701,6 @@ int PrescoDemod(uint8_t *dest, size_t *size) {
return (int) startIdx;
}
// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
// BitStream must contain previously askrawdemod and biphasedemoded data
int FDXBdemodBI(uint8_t *dest, size_t *size)
@ -1495,8 +1499,8 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
numBits += (firstFullWave / *clock);
//set start of wave as clock align
lastClkBit = firstFullWave;
//PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
//PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit);
if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
if (g_debugMode==2) prnt("DEBUG: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
waveStart = 0;
dest[numBits++] = curPhase; //set first read bit
for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
@ -1679,7 +1683,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
i=0;
// warning - overwriting buffer given with raw wave data with ST removed...
while ( dataloc < bufsize-(clk/2) ) {
//compensate for long high at end of ST not being high... (we cut out the high part)
//compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part)
if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
for(i=0; i < clk/2-tol; ++i) {
buffer[dataloc+i] = high+5;
@ -1694,7 +1698,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
}
}
newloc += i;
//skip next ST
//skip next ST - we just assume it will be there from now on...
dataloc += clk*4;
}
*size = newloc;