signalVector: Implement segment().

Change-Id: I6fe3aae53fb2fa5bb7637e976de6059eabe08202
diff --git a/Transceiver52M/signalVector.cpp b/Transceiver52M/signalVector.cpp
index 798a3c7..55dad92 100644
--- a/Transceiver52M/signalVector.cpp
+++ b/Transceiver52M/signalVector.cpp
@@ -45,6 +45,11 @@
 	mStart = mData + vector.getStart();
 }
 
+signalVector signalVector::segment(size_t start, size_t span)
+{
+	return signalVector(mData, start, span);
+}
+
 size_t signalVector::getStart() const
 {
 	return mStart - mData;