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lf psk demods

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clarify existing as psk1
added psk2 demod
This commit is contained in:
marshmellow42 2015-01-26 17:23:19 -05:00
commit 04d2721b3c
3 changed files with 63 additions and 23 deletions
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32
common/lfdemod.c
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@ -816,7 +816,6 @@ int PyramiddemodFSK(uint8_t *dest, size_t size)
return -4;
}
// by marshmellow
// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
// maybe somehow adjust peak trimming value based on samples to fix?
@ -885,7 +884,6 @@ int DetectASKClock(uint8_t dest[], size_t size, int clock)
return clk[best];
}
//by marshmellow
//detect psk clock by reading #peaks vs no peaks(or errors)
int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
@ -963,7 +961,7 @@ int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
return clk[best];
}
//by marshmellow (attempt to get rid of high immediately after a low)
// by marshmellow (attempt to get rid of high immediately after a low)
void pskCleanWave(uint8_t *BitStream, size_t size)
{
int i;
@ -999,9 +997,26 @@ void pskCleanWave(uint8_t *BitStream, size_t size)
return;
}
// by marshmellow
// convert psk1 demod to psk2 demod
// only transition waves are 1s
void psk1TOpsk2(uint8_t *BitStream, size_t size)
{
size_t i=1;
uint8_t lastBit=BitStream[0];
for (; i<size; i++){
if (lastBit!=BitStream[i]){
lastBit=BitStream[i];
BitStream[i]=1;
} else {
BitStream[i]=0;
}
}
return;
}
//redesigned by marshmellow adjusted from existing decode functions
//indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
// redesigned by marshmellow adjusted from existing decode functions
// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
{
//26 bit 40134 format (don't know other formats)
@ -1064,9 +1079,8 @@ int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
return 1;
}
//by marshmellow - demodulate PSK1 wave or NRZ wave (both similar enough)
//peaks switch bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
// by marshmellow - demodulate PSK1 wave or NRZ wave (both similar enough)
// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert)
{
pskCleanWave(dest,*size);
@ -1087,7 +1101,6 @@ int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert)
uint32_t bestStart = *size;
uint32_t maxErr = (*size/1000);
uint32_t bestErrCnt = maxErr;
//uint8_t midBit=0;
uint8_t curBit=0;
uint8_t bitHigh=0;
uint8_t ignorewin=*clk/8;
@ -1198,7 +1211,6 @@ int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert)
return errCnt;
}
//by marshmellow
//detects the bit clock for FSK given the high and low Field Clocks
uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)