sigproc: Add various GSM burst generators

Setup generators for empty, random, and dummy bursts. This moves error
prone burst length handling out of the Transceiver and into the signal
processing core.

Signed-off-by: Tom Tsou <tom.tsou@ettus.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/Transceiver52M/sigProcLib.cpp b/Transceiver52M/sigProcLib.cpp
index 1a15e51..cf2c257 100644
--- a/Transceiver52M/sigProcLib.cpp
+++ b/Transceiver52M/sigProcLib.cpp
@@ -965,6 +965,68 @@ static signalVector *shapeEdgeBurst(const signalVector &symbols)
 }
 
 /*
+ * Generate a random GSM normal burst.
+ */
+signalVector *genRandNormalBurst(int tsc, int sps, int tn)
+{
+  if ((tsc < 0) || (tsc > 7) || (tn < 0) || (tn > 7))
+    return NULL;
+  if ((sps != 1) && (sps != 4))
+    return NULL;
+
+  int i = 0;
+  BitVector *bits = new BitVector(148);
+  signalVector *burst;
+
+  /* Tail bits */
+  for (; i < 4; i++)
+    (*bits)[i] = 0;
+
+  /* Random bits */
+  for (; i < 61; i++)
+    (*bits)[i] = rand() % 2;
+
+  /* Training sequence */
+  for (int n = 0; i < 87; i++, n++)
+    (*bits)[i] = gTrainingSequence[tsc][n];
+
+  /* Random bits */
+  for (; i < 144; i++)
+    (*bits)[i] = rand() % 2;
+
+  /* Tail bits */
+  for (; i < 148; i++)
+    (*bits)[i] = 0;
+
+  int guard = 8 + !(tn % 4);
+  burst = modulateBurst(*bits, guard, sps);
+  delete bits;
+
+  return burst;
+}
+
+signalVector *generateEmptyBurst(int sps, int tn)
+{
+	if ((tn < 0) || (tn > 7))
+		return NULL;
+
+	if (sps == 4)
+		return new signalVector(625);
+	else if (sps == 1)
+		return new signalVector(148 + 8 + !(tn % 4));
+	else
+		return NULL;
+}
+
+signalVector *generateDummyBurst(int sps, int tn)
+{
+	if (((sps != 1) && (sps != 4)) || (tn < 0) || (tn > 7))
+		return NULL;
+
+	return modulateBurst(gDummyBurst, 8 + !(tn % 4), sps);
+}
+
+/*
  * Generate a random 8-PSK EDGE burst. Only 4 SPS is supported with
  * the returned burst being 625 samples in length.
  */