fix correlation detection

dsp.c

@@ -65,10 +65,10 @@ dsp_process(int16_t *capture, size_t length)
     samp_buf[i] = smp;
     int32_t s = sincos_tbl[i][0];
     int32_t c = sincos_tbl[i][1];
-    samp_s += smp * s / 64;
-    samp_c += smp * c / 64;
-    ref_s += ref * s / 64;
-    ref_c += ref * c / 64;
+    samp_s += smp * s / 16;
+    samp_c += smp * c / 16;
+    ref_s += ref * s / 16;
+    ref_c += ref * c / 16;
 #if 0
     uint32_t sc = *(uint32_t)&sincos_tbl[i];
     samp_s = __SMLABB(sr, sc, samp_s);
@@ -92,7 +92,7 @@ calculate_gamma(float gamma[2])
   float ss = acc_samp_s;
   float sc = acc_samp_c;
   gamma[0] =  (sc * rc + ss * rs) / rr;
-  gamma[1] = (sc * rs - sc * rc) / rr;
+  gamma[1] =  (ss * rc - sc * rs) / rr;
 }
 
 void

main.c

@@ -452,7 +452,7 @@ void sweep(void)
 
  rewind:
   frequency_updated = FALSE;
-  delay = 5;
+  delay = 3;
 
   for (i = 0; i < sweep_points; i++) {
     set_frequency(frequencies[i]);