+}
+
+/* Sliding DFT
+ Smooths out
+*/
+void iceFsk2(int * data, const size_t len){
+
+ int i, j;
+ int * output = (int* ) malloc(sizeof(int) * len);
+ memset(output, 0x00, len);
+
+ // for (i=0; i<len-5; ++i){
+ // for ( j=1; j <=5; ++j) {
+ // output[i] += data[i*j];
+ // }
+ // output[i] /= 5;
+ // }
+ int rest = 127;
+ int tmp =0;
+ for (i=0; i<len; ++i){
+ if ( data[i] < 127)
+ output[i] = 0;
+ else {
+ tmp = (100 * (data[i]-rest)) / rest;
+ output[i] = (tmp > 60)? 100:0;
+ }
+ }
+
+ for (j=0; j<len; ++j)
+ data[j] = output[j];
+
+ free(output);
+}
+
+void iceFsk3(int * data, const size_t len){
+
+ int i,j;
+
+ int * output = (int* ) malloc(sizeof(int) * len);
+ memset(output, 0x00, len);
+ float fc = 0.1125f; // center frequency
+ size_t adjustedLen = len;
+
+ // create very simple low-pass filter to remove images (2nd-order Butterworth)
+ float complex iir_buf[3] = {0,0,0};
+ float b[3] = {0.003621681514929, 0.007243363029857, 0.003621681514929};
+ float a[3] = {1.000000000000000, -1.822694925196308, 0.837181651256023};
+
+ float sample = 0; // input sample read from file
+ float complex x_prime = 1.0f; // save sample for estimating frequency
+ float complex x;
+
+ for (i=0; i<adjustedLen; ++i) {
+
+ sample = data[i]+128;
+
+ // remove DC offset and mix to complex baseband
+ x = (sample - 127.5f) * cexpf( _Complex_I * 2 * M_PI * fc * i );
+
+ // apply low-pass filter, removing spectral image (IIR using direct-form II)
+ iir_buf[2] = iir_buf[1];
+ iir_buf[1] = iir_buf[0];
+ iir_buf[0] = x - a[1]*iir_buf[1] - a[2]*iir_buf[2];
+ x = b[0]*iir_buf[0] +
+ b[1]*iir_buf[1] +
+ b[2]*iir_buf[2];
+
+ // compute instantaneous frequency by looking at phase difference
+ // between adjacent samples
+ float freq = cargf(x*conjf(x_prime));
+ x_prime = x; // retain this sample for next iteration
+
+ output[i] =(freq > 0)? 10 : -10;
+ }
+
+ // show data
+ for (j=0; j<adjustedLen; ++j)
+ data[j] = output[j];
+
+ CmdLtrim("30");
+ adjustedLen -= 30;
+
+ // zero crossings.
+ for (j=0; j<adjustedLen; ++j){
+ if ( data[j] == 10) break;
+ }
+ int startOne =j;
+
+ for (;j<adjustedLen; ++j){
+ if ( data[j] == -10 ) break;
+ }
+ int stopOne = j-1;
+
+ int fieldlen = stopOne-startOne;
+
+ fieldlen = (fieldlen == 39 || fieldlen == 41)? 40 : fieldlen;
+ fieldlen = (fieldlen == 59 || fieldlen == 51)? 50 : fieldlen;
+ if ( fieldlen != 40 && fieldlen != 50){
+ printf("Detected field Length: %d \n", fieldlen);
+ printf("Can only handle 40 or 50. Aborting...\n");
+ return;
+ }
+
+ // FSK sequence start == 000111
+ int startPos = 0;
+ for (i =0; i<adjustedLen; ++i){
+ int dec = 0;
+ for ( j = 0; j < 6*fieldlen; ++j){
+ dec += data[i + j];
+ }
+ if (dec == 0) {
+ startPos = i;
+ break;
+ }
+ }
+
+ printf("000111 position: %d \n", startPos);
+
+ startPos += 6*fieldlen+5;
+
+ int bit =0;
+ printf("BINARY\n");
+ printf("R/40 : ");
+ for (i =startPos ; i < adjustedLen; i += 40){
+ bit = data[i]>0 ? 1:0;
+ printf("%d", bit );
+ }
+ printf("\n");
+
+ printf("R/50 : ");
+ for (i =startPos ; i < adjustedLen; i += 50){
+ bit = data[i]>0 ? 1:0;
+ printf("%d", bit ); }
+ printf("\n");
+
+ free(output);
+}
+
+float complex cexpf (float complex Z)
+{
+ float complex Res;
+ double rho = exp (__real__ Z);
+ __real__ Res = rho * cosf(__imag__ Z);
+ __imag__ Res = rho * sinf(__imag__ Z);
+ return Res;
+}
projects / proxmark3-svn / blobdiff