From ee5347af4004831ed38781b52a62a84ed9d3a076 Mon Sep 17 00:00:00 2001
From: "kurtis.heimerl" <kurtis.heimerl@19bc5d8c-e614-43d4-8b26-e1612bc8e597>
Date: Sat, 26 Nov 2011 03:18:05 +0000
Subject: transceiver: reinsert digital gain scaling

Commit e161523c (transceiver: simplify transmit power control)
changed transmit gain control to RF setting only. This was
appropriate for a WBX board with 25 dB of gain control, but
inappropriate for an RFX with fixed transmit gain.

RFX boards will regain the ability to set transmit
attenuation. Since gain is set on the RF side first,
reintroducing digital gain settings should have limited
overall effect on non-RFX daughterboards.

Signed-off-by: Thomas Tsou <ttsou@vt.edu>

git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@2660 19bc5d8c-e614-43d4-8b26-e1612bc8e597
---
 Transceiver52M/radioInterface.cpp | 27 ++++++++++++++++++++++-----
 Transceiver52M/radioInterface.h   |  5 ++++-
 2 files changed, 26 insertions(+), 6 deletions(-)

(limited to 'Transceiver52M')

diff --git a/Transceiver52M/radioInterface.cpp b/Transceiver52M/radioInterface.cpp
index 3e654b1..1afa01b 100644
--- a/Transceiver52M/radioInterface.cpp
+++ b/Transceiver52M/radioInterface.cpp
@@ -84,6 +84,7 @@ RadioInterface::RadioInterface(RadioDevice *wRadio,
   samplesPerSymbol = wRadioOversampling;
   mClock.set(wStartTime);
   loadTest = false;
+  powerScaling = 1.0;
 }
 
 RadioInterface::~RadioInterface(void) {
@@ -102,10 +103,21 @@ double RadioInterface::fullScaleOutputValue(void) {
 
 void RadioInterface::setPowerAttenuation(double atten)
 {
-  mRadio->setTxGain(mRadio->maxTxGain() - atten);
+  double rfAtten, digAtten;
+
+  rfAtten = mRadio->setTxGain(mRadio->maxTxGain() - atten);
+  digAtten = atten - rfAtten;
+
+  if (digAtten < 1.0)
+    powerScaling = 1.0;
+  else
+    powerScaling = 1.0/sqrt(pow(10, (digAtten/10.0)));
 }
 
-short *RadioInterface::radioifyVector(signalVector &wVector, short *retVector, bool zeroOut) 
+short *RadioInterface::radioifyVector(signalVector &wVector,
+                                      short *retVector,
+                                      float scale,
+                                      bool zeroOut)
 {
   signalVector::iterator itr = wVector.begin();
   short *shortItr = retVector;
@@ -115,8 +127,13 @@ short *RadioInterface::radioifyVector(signalVector &wVector, short *retVector, b
       *shortItr++ = 0;
       itr++;
     }
-  }
-  else {
+  } else if (scale != 1.0) { 
+    while (itr < wVector.end()) {
+      *shortItr++ = (short) (itr->real() * scale);
+      *shortItr++ = (short) (itr->imag() * scale);
+      itr++;
+    }
+  } else {
     while (itr < wVector.end()) {
       *shortItr++ = (short) (itr->real());
       *shortItr++ = (short) (itr->imag());
@@ -237,7 +254,7 @@ void RadioInterface::driveTransmitRadio(signalVector &radioBurst, bool zeroBurst
 
   if (!mOn) return;
 
-  radioifyVector(radioBurst, sendBuffer+sendCursor, zeroBurst);
+  radioifyVector(radioBurst, sendBuffer+sendCursor, powerScaling, zeroBurst);
 
   sendCursor += (radioBurst.size()*2);
 
diff --git a/Transceiver52M/radioInterface.h b/Transceiver52M/radioInterface.h
index d19f88d..71273b3 100644
--- a/Transceiver52M/radioInterface.h
+++ b/Transceiver52M/radioInterface.h
@@ -157,7 +157,10 @@ private:
   signalVector *finalVec, *finalVec9;
 
   /** format samples to USRP */ 
-  short *radioifyVector(signalVector &wVector, short *shortVector, bool zeroOut);
+  short *radioifyVector(signalVector &wVector,
+                        short *shortVector,
+                        float scale,
+                        bool zeroOut);
 
   /** format samples from USRP */
   void unRadioifyVector(short *shortVector, signalVector &wVector);
-- 
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