Transceiver52M: Update noise measurement calculation

Previous removal of the energy detector requirement broke
the noise level calculation loop. The previous adaptive
approach was finicky - noticably at high gain levels. Since
we no longer use the energy threshold for primary burst gating,
we can return to a simpler world.

In the new approach, we compute a running average of energy
levels and track them with a noise vector. A timeslot that
passes the correlator threshold is a valid burst. These are
not used in the noise calculation. Everything else is
considered noise and used to compute the noise level with
respect to full scale input level, which for almost all
supported devices is 2^15.

Signed-off-by: Thomas Tsou <tom@tsou.cc>

1 files changed, 10 insertions, 0 deletions

diff --git a/Transceiver52M/radioVector.h b/Transceiver52M/radioVector.h
index 8de4493..8dc1c13 100644
--- a/Transceiver52M/radioVector.h
+++ b/Transceiver52M/radioVector.h
@@ -37,6 +37,16 @@ private:
 	GSM::Time mTime;
 };
 
+class noiseVector : std::vector<float> {
+public:
+	noiseVector(size_t len = 0);
+	bool insert(float val);
+	float avg();
+
+private:
+	std::vector<float>::iterator it;
+};
+
 class VectorFIFO {
 public:
 	unsigned size();