Fix start-of_burst for PRACH Test USRP

lib/src/phy/phch/test/prach_test_usrp.c

@@ -265,11 +265,13 @@ int main(int argc, char** argv)
   double   peak_avg     = 0.0;
   uint32_t count        = 0;
 
-  // Perform experiment for given a number of repetitions
-  for (uint32_t rep = 0; rep < nof_repetitions; rep++) {
   // First transmission shall be flagged as start of burst
   bool is_start_of_burst = true;
 
+  // Perform experiment for given a number of repetitions
+  for (uint32_t rep = 0; rep < nof_repetitions; rep++) {
+    is_start_of_burst |= !continous_tx;
+
     // For a the number of frames
     for (uint32_t nframe = 0; nframe < nof_frames; nframe++) {
       INFO("Rep %d. Receiving frame %d\n", rep, nframe);