sdrangel/sdrbase/dsp/devicesamplesource.cpp

134 lines
5.0 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2015-2017 F4EXB //
// written by Edouard Griffiths //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation as version 3 of the License, or //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////
#include <QDebug>
#include <dsp/devicesamplesource.h>
DeviceSampleSource::DeviceSampleSource() :
m_guiMessageQueue(0)
{
connect(&m_inputMessageQueue, SIGNAL(messageEnqueued()), this, SLOT(handleInputMessages()));
}
DeviceSampleSource::~DeviceSampleSource()
{
}
void DeviceSampleSource::handleInputMessages()
{
Message* message;
while ((message = m_inputMessageQueue.pop()) != 0)
{
if (handleMessage(*message))
{
delete message;
}
}
}
qint64 DeviceSampleSource::calculateDeviceCenterFrequency(
quint64 centerFrequency,
qint64 transverterDeltaFrequency,
int log2Decim,
fcPos_t fcPos,
quint32 devSampleRate,
bool transverterMode)
{
qint64 deviceCenterFrequency = centerFrequency;
deviceCenterFrequency -= transverterMode ? transverterDeltaFrequency : 0;
deviceCenterFrequency = deviceCenterFrequency < 0 ? 0 : deviceCenterFrequency;
qint64 f_img = deviceCenterFrequency;
deviceCenterFrequency -= calculateFrequencyShift(log2Decim, fcPos, devSampleRate);
f_img -= 2*calculateFrequencyShift(log2Decim, fcPos, devSampleRate);
qDebug() << "DeviceSampleSource::calculateDeviceCenterFrequency:"
<< " desired center freq: " << centerFrequency << " Hz"
<< " device center freq: " << deviceCenterFrequency << " Hz"
<< " device sample rate: " << devSampleRate << "S/s"
<< " Actual sample rate: " << devSampleRate/(1<<log2Decim) << "S/s"
<< " center freq position code: " << fcPos
<< " image frequency: " << f_img << "Hz";
return deviceCenterFrequency;
}
qint64 DeviceSampleSource::calculateCenterFrequency(
quint64 deviceCenterFrequency,
qint64 transverterDeltaFrequency,
int log2Decim,
fcPos_t fcPos,
quint32 devSampleRate,
bool transverterMode)
{
qint64 centerFrequency = deviceCenterFrequency;
centerFrequency += calculateFrequencyShift(log2Decim, fcPos, devSampleRate);
centerFrequency += transverterMode ? transverterDeltaFrequency : 0;
centerFrequency = centerFrequency < 0 ? 0 : centerFrequency;
qDebug() << "DeviceSampleSource::calculateCenterFrequency:"
<< " desired center freq: " << centerFrequency << " Hz"
<< " device center freq: " << deviceCenterFrequency << " Hz"
<< " device sample rate: " << devSampleRate << "S/s"
<< " Actual sample rate: " << devSampleRate/(1<<log2Decim) << "S/s"
<< " center freq position code: " << fcPos;
return centerFrequency;
}
/**
* log2Decim = 0: no shift
*
* n = log2Decim <= 2: fc = +/- 1/2^(n-1)
* center
* | ^ |
* | inf | sup |
* ^ ^
*
* n = log2Decim > 2: fc = +/- 1/2^n
* center
* | ^ |
* | |inf| | |sup| |
* ^ ^
*/
qint32 DeviceSampleSource::calculateFrequencyShift(
int log2Decim,
fcPos_t fcPos,
quint32 devSampleRate)
{
if (log2Decim == 0) { // no shift at all
return 0;
} else if (log2Decim < 3) {
if (fcPos == FC_POS_INFRA) { // shift in the square next to center frequency
return -(devSampleRate / (1<<(log2Decim+1)));
} else if (fcPos == FC_POS_SUPRA) {
return devSampleRate / (1<<(log2Decim+1));
} else {
return 0;
}
} else {
if (fcPos == FC_POS_INFRA) { // shift centered in the square next to center frequency
return -(devSampleRate / (1<<(log2Decim)));
} else if (fcPos == FC_POS_SUPRA) {
return devSampleRate / (1<<(log2Decim));
} else {
return 0;
}
}
}