From 1dd05cf35a8c5e3c2acfbc4e23e26d41ea4a9aa9 Mon Sep 17 00:00:00 2001
From: Alexander Chemeris <Alexander.Chemeris@gmail.com>
Date: Wed, 15 Mar 2017 23:23:36 +0300
Subject: sigProcLib: make energyDetect() simpler by returning actual energy.

Change-Id: I9bf97f2dc03fea9bebcf43198dfb05f6e4694e9c
---
 Transceiver52M/Transceiver.cpp |  4 ++--
 Transceiver52M/sigProcLib.cpp  |  8 ++------
 Transceiver52M/sigProcLib.h    | 14 +++++---------
 3 files changed, 9 insertions(+), 17 deletions(-)

(limited to 'Transceiver52M')

diff --git a/Transceiver52M/Transceiver.cpp b/Transceiver52M/Transceiver.cpp
index f156ad4..3df482f 100644
--- a/Transceiver52M/Transceiver.cpp
+++ b/Transceiver52M/Transceiver.cpp
@@ -606,7 +606,7 @@ SoftVector *Transceiver::pullRadioVector(GSM::Time &wTime, double &RSSI, bool &i
 {
   int rc;
   complex amp;
-  float toa, pow, max = -1.0, avg = 0.0;
+  float toa, max = -1.0, avg = 0.0;
   int max_i = -1;
   signalVector *burst;
   SoftVector *bits = NULL;
@@ -641,7 +641,7 @@ SoftVector *Transceiver::pullRadioVector(GSM::Time &wTime, double &RSSI, bool &i
 
   /* Select the diversity channel with highest energy */
   for (size_t i = 0; i < radio_burst->chans(); i++) {
-    energyDetect(*radio_burst->getVector(i), 20 * mSPSRx, 0.0, &pow);
+    float pow = energyDetect(*radio_burst->getVector(i), 20 * mSPSRx);
     if (pow > max) {
       max = pow;
       max_i = i;
diff --git a/Transceiver52M/sigProcLib.cpp b/Transceiver52M/sigProcLib.cpp
index c1cf12e..41b18cf 100644
--- a/Transceiver52M/sigProcLib.cpp
+++ b/Transceiver52M/sigProcLib.cpp
@@ -1721,10 +1721,7 @@ static float computePeakRatio(signalVector *corr,
   return (amp.abs()) / rms;
 }
 
-bool energyDetect(signalVector &rxBurst,
-		  unsigned windowLength,
-		  float detectThreshold,
-                  float *avgPwr)
+float energyDetect(signalVector &rxBurst, unsigned windowLength)
 {
 
   signalVector::const_iterator windowItr = rxBurst.begin(); //+rxBurst.size()/2 - 5*windowLength/2;
@@ -1735,8 +1732,7 @@ bool energyDetect(signalVector &rxBurst,
     energy += windowItr->norm2();
     windowItr+=4;
   }
-  if (avgPwr) *avgPwr = energy/windowLength;
-  return (energy/windowLength > detectThreshold*detectThreshold);
+  return energy/windowLength;
 }
 
 /*
diff --git a/Transceiver52M/sigProcLib.h b/Transceiver52M/sigProcLib.h
index 1b646cd..87c0229 100644
--- a/Transceiver52M/sigProcLib.h
+++ b/Transceiver52M/sigProcLib.h
@@ -176,17 +176,13 @@ void scaleVector(signalVector &x,
 		 complex scale);
 
 /**
-        Energy detector, checks to see if received burst energy is above a threshold.
-        @param rxBurst The received GSM burst of interest.
+        Rough energy estimator.
+        @param rxBurst A GSM burst.
         @param windowLength The number of burst samples used to compute burst energy
-        @param detectThreshold The detection threshold, a linear value.
-        @param avgPwr The average power of the received burst.
-        @return True if burst energy is above threshold.
+        @return The average power of the received burst.
 */
-bool energyDetect(signalVector &rxBurst,
-		  unsigned windowLength,
-                  float detectThreshold,
-                  float *avgPwr = NULL);
+float energyDetect(signalVector &rxBurst,
+                   unsigned windowLength);
 
 /**
         RACH aka Access Burst correlator/detector.
-- 
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