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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>
This commit is contained in:
Thomas Tsou 2011-06-22 13:24:15 -07:00
parent 8301298f88
commit 6d34bace87
4 changed files with 39 additions and 8 deletions

View File

@ -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);

View File

@ -142,6 +142,8 @@ private:
bool mOn; ///< indicates radio is on
float powerScaling;
/** format samples to USRP */
short *USRPifyVector(signalVector &wVector);

View File

@ -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);

View File

@ -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);