From 6d34bace870748e4def6cd6b1ec526eff3d4aac7 Mon Sep 17 00:00:00 2001
From: Thomas Tsou <ttsou@vt.edu>
Date: Wed, 22 Jun 2011 13:24:15 -0700
Subject: [PATCH] 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>
---
 public-trunk/Transceiver/radioInterface.cpp   | 13 +++++++--
 public-trunk/Transceiver/radioInterface.h     |  2 ++
 .../Transceiver52M/radioInterface.cpp         | 27 +++++++++++++++----
 public-trunk/Transceiver52M/radioInterface.h  |  5 +++-
 4 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/public-trunk/Transceiver/radioInterface.cpp b/public-trunk/Transceiver/radioInterface.cpp
index d38fb30..d3b5ec8 100644
--- a/public-trunk/Transceiver/radioInterface.cpp
+++ b/public-trunk/Transceiver/radioInterface.cpp
@@ -58,6 +58,7 @@ RadioInterface::RadioInterface(RadioDevice *wUsrp,
   receiveOffset = wReceiveOffset;
   samplesPerSymbol = wSamplesPerSymbol;
   mClock.set(wStartTime);
+  powerScaling = 1.0;
 }
 
 RadioInterface::~RadioInterface(void) {
@@ -81,7 +82,15 @@ double RadioInterface::fullScaleOutputValue(void) {
 
 void RadioInterface::setPowerAttenuation(double atten)
 {
-  usrp->setTxGain(usrp->maxTxGain() - atten);
+  double rfAtten, digAtten;
+
+  rfAtten = usrp->setTxGain(usrp->maxTxGain() - atten);
+  digAtten = atten - rfAtten;
+
+  if (digAtten < 1.0)
+    powerScaling = 1.0;
+  else
+    powerScaling = 1.0/sqrt(pow(10, (digAtten/10.0)));
 }
 
 short *RadioInterface::USRPifyVector(signalVector &wVector) 
@@ -149,7 +158,7 @@ void RadioInterface::pushBuffer(void) {
   delete inputVector;
  
   // Set transmit gain and power here.
-  scaleVector(*resampledVector, usrp->fullScaleInputValue());
+  scaleVector(*resampledVector, powerScaling * usrp->fullScaleInputValue());
 
   short *resampledVectorShort = USRPifyVector(*resampledVector);
 
diff --git a/public-trunk/Transceiver/radioInterface.h b/public-trunk/Transceiver/radioInterface.h
index 94d0166..e2d4336 100644
--- a/public-trunk/Transceiver/radioInterface.h
+++ b/public-trunk/Transceiver/radioInterface.h
@@ -142,6 +142,8 @@ private:
 
   bool mOn;				      ///< indicates radio is on
 
+  float powerScaling;
+
   /** format samples to USRP */ 
   short *USRPifyVector(signalVector &wVector);
 
diff --git a/public-trunk/Transceiver52M/radioInterface.cpp b/public-trunk/Transceiver52M/radioInterface.cpp
index add4c3c..5a4ad20 100644
--- a/public-trunk/Transceiver52M/radioInterface.cpp
+++ b/public-trunk/Transceiver52M/radioInterface.cpp
@@ -91,6 +91,7 @@ RadioInterface::RadioInterface(RadioDevice *wRadio,
   receiveOffset = wReceiveOffset;
   samplesPerSymbol = wRadioOversampling;
   mClock.set(wStartTime);
+  powerScaling = 1.0;
 }
 
 RadioInterface::~RadioInterface(void) {
@@ -108,10 +109,21 @@ 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;
@@ -121,8 +133,13 @@ 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());
@@ -238,7 +255,7 @@ 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/public-trunk/Transceiver52M/radioInterface.h b/public-trunk/Transceiver52M/radioInterface.h
index b9ae608..27dfc14 100644
--- a/public-trunk/Transceiver52M/radioInterface.h
+++ b/public-trunk/Transceiver52M/radioInterface.h
@@ -161,7 +161,10 @@ private:
   double powerScaling;
 
   /** 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);