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sdrangel/plugins/channel/usb/usbdemod.cpp

128 lines
4.2 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2012 maintech GmbH, Otto-Hahn-Str. 15, 97204 Hoechberg, Germany //
// written by Christian Daniel //
// (c) 2014 Modified by John Greb
// //
// 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 <QTime>
#include <stdio.h>
#include "usbdemod.h"
#include "audio/audiooutput.h"
#include "dsp/dspcommands.h"
MESSAGE_CLASS_DEFINITION(USBDemod::MsgConfigureUSBDemod, Message)
USBDemod::USBDemod(AudioFifo* audioFifo, SampleSink* sampleSink) :
m_sampleSink(sampleSink),
m_audioFifo(audioFifo)
{
m_Bandwidth = 5000;
m_volume = 2.0;
m_sampleRate = 96000;
m_frequency = 0;
m_audioBuffer.resize(512);
m_audioBufferFill = 0;
m_undersampleCount = 0;
USBFilter = new fftfilt(0.01, m_Bandwidth / 96000.0, usbFftLen);
// if (!USBFilter) segfault;
}
USBDemod::~USBDemod()
{
if (USBFilter) delete USBFilter;
}
void USBDemod::configure(MessageQueue* messageQueue, Real Bandwidth, Real volume)
{
Message* cmd = MsgConfigureUSBDemod::create(Bandwidth, volume);
cmd->submit(messageQueue, this);
}
/* Expects samplerate as multiples of 96kHz. */
void USBDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iterator end, bool positiveOnly)
{
Real a, b;
Complex c;
int n_out;
cmplx *sideband;
bool consumed;
int samplestep = m_sampleRate / 96000;
if (samplestep < 1 )
samplestep = 1;
for(SampleVector::const_iterator it = begin; it < end; it += samplestep) {
a = it->real();
b = it->imag();
c = Complex(a / 65536.0, b / 65536.0);
n_out = USBFilter->run(c, &sideband, true);
for (int i = 0; i < n_out; i+=2) {
Real demod = (sideband[i].real() + sideband[i].imag()) * 32768.0;
// Downsample by 4x for audio display
if (!(m_undersampleCount++ & 3))
m_sampleBuffer.push_back(Sample(demod, 0.0));
qint16 sample = (qint16)(demod * m_volume);
m_audioBuffer[m_audioBufferFill].l = sample;
m_audioBuffer[m_audioBufferFill].r = sample;
++m_audioBufferFill;
if(m_audioBufferFill >= m_audioBuffer.size()) {
uint res = m_audioFifo->write((const quint8*)&m_audioBuffer[0], m_audioBufferFill, 1);
m_audioBufferFill = 0;
}
}
}
if(m_audioFifo->write((const quint8*)&m_audioBuffer[0], m_audioBufferFill, 0) != m_audioBufferFill)
;//qDebug("lost samples");
m_audioBufferFill = 0;
if(m_sampleSink != NULL)
m_sampleSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), true);
m_sampleBuffer.clear();
}
void USBDemod::start()
{
}
void USBDemod::stop()
{
}
bool USBDemod::handleMessage(Message* cmd)
{
if(DSPSignalNotification::match(cmd)) {
DSPSignalNotification* signal = (DSPSignalNotification*)cmd;
m_sampleRate = signal->getSampleRate();
cmd->completed();
return true;
} else if(MsgConfigureUSBDemod::match(cmd)) {
MsgConfigureUSBDemod* cfg = (MsgConfigureUSBDemod*)cmd;
m_Bandwidth = cfg->getBandwidth();
USBFilter->create_filter(0.3 / 96.0, m_Bandwidth / 96000.0);
m_volume = cfg->getVolume();
m_volume *= m_volume * 0.1;
cmd->completed();
return true;
} else {
if(m_sampleSink != NULL)
return m_sampleSink->handleMessage(cmd);
else return false;
}
}