lf psk demods

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 34194394deea0ded2029bbe3e173a7261c36fc7e..810e0357bd77873c8e6b182ef0e66194abe10139 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -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)