mirror of
https://github.com/f4exb/sdrangel.git
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111 lines
4.0 KiB
C++
111 lines
4.0 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2015-2017 F4EXB //
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// written by Edouard Griffiths //
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// //
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// This program is free software; you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation as version 3 of the License, or //
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// //
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// This program is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License V3 for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with this program. If not, see <http://www.gnu.org/licenses/>. //
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///////////////////////////////////////////////////////////////////////////////////
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#include <QDebug>
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#include <dsp/devicesamplesource.h>
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DeviceSampleSource::DeviceSampleSource() :
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m_guiMessageQueue(0)
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{
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connect(&m_inputMessageQueue, SIGNAL(messageEnqueued()), this, SLOT(handleInputMessages()));
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}
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DeviceSampleSource::~DeviceSampleSource()
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{
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}
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void DeviceSampleSource::handleInputMessages()
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{
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Message* message;
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while ((message = m_inputMessageQueue.pop()) != 0)
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{
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if (handleMessage(*message))
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{
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delete message;
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}
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}
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}
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qint64 DeviceSampleSource::calculateDeviceCenterFrequency(
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quint64 centerFrequency,
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qint64 transverterDeltaFrequency,
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int log2Decim,
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fcPos_t fcPos,
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quint32 devSampleRate,
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bool transverterMode)
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{
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qint64 deviceCenterFrequency = centerFrequency;
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deviceCenterFrequency -= transverterMode ? transverterDeltaFrequency : 0;
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deviceCenterFrequency = deviceCenterFrequency < 0 ? 0 : deviceCenterFrequency;
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qint64 f_img = deviceCenterFrequency;
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deviceCenterFrequency -= calculateFrequencyShift(log2Decim, fcPos, devSampleRate);
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f_img -= 2*calculateFrequencyShift(log2Decim, fcPos, devSampleRate);
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qDebug() << "DeviceSampleSource::calculateDeviceCenterFrequency:"
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<< " desired center freq: " << centerFrequency << " Hz"
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<< " device center freq: " << deviceCenterFrequency << " Hz"
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<< " device sample rate: " << devSampleRate << "S/s"
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<< " Actual sample rate: " << devSampleRate/(1<<log2Decim) << "S/s"
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<< " center freq position code: " << fcPos
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<< " image frequency: " << f_img << "Hz";
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return deviceCenterFrequency;
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}
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/**
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* log2Decim = 0: no shift
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*
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* n = log2Decim <= 2: fc = +/- 1/2^(n-1)
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* center
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* | ^ |
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* | inf | sup |
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* ^ ^
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*
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* n = log2Decim > 2: fc = +/- 1/2^n
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* center
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* | ^ |
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* | |inf| | |sup| |
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* ^ ^
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*/
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qint32 DeviceSampleSource::calculateFrequencyShift(
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int log2Decim,
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fcPos_t fcPos,
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quint32 devSampleRate)
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{
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if (log2Decim == 0) { // no shift at all
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return 0;
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} else if (log2Decim < 3) {
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if (fcPos == FC_POS_INFRA) { // shift in the square next to center frequency
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return -(devSampleRate / (1<<(log2Decim+1)));
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} else if (fcPos == FC_POS_SUPRA) {
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return devSampleRate / (1<<(log2Decim+1));
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} else {
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return 0;
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}
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} else {
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if (fcPos == FC_POS_INFRA) { // shift centered in the square next to center frequency
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return -(devSampleRate / (1<<(log2Decim)));
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} else if (fcPos == FC_POS_SUPRA) {
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return devSampleRate / (1<<(log2Decim));
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} else {
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return 0;
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}
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}
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}
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