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Sound generator: allow periods of silence between tones

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Klaus Basan
2014-02-05 20:57:30 +00:00
committed by Mathew Sutcliffe
parent 489de7642b
commit 7b0dff1af5
1 changed files with 26 additions and 4 deletions
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30
src/blacksound/soundgenerator.cpp
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@@ -4,6 +4,9 @@
#include <qendian.h>
#include <QAudioOutput>
using namespace BlackMisc::Aviation;
using namespace BlackMisc::PhysicalQuantities;
namespace BlackSound
{
CSoundGenerator::CSoundGenerator(const QAudioFormat &format, const QList<Tone> &tones, bool singlePlay, QObject *parent)
@@ -66,10 +69,15 @@ namespace BlackSound
// http://hyperphysics.phy-astr.gsu.edu/hbase/audio/sumdif.html
// http://math.stackexchange.com/questions/164369/how-do-you-calculate-the-frequency-perceived-by-humans-of-two-sinusoidal-waves-a
const double pseudoTime = double(sampleIndexPerTone % format.sampleRate()) / format.sampleRate();
const double amplitude = t.m_secondaryFrequencyHz == 0 ?
qSin(2 * M_PI * t.m_frequencyHz * pseudoTime) :
qSin(M_PI * (t.m_frequencyHz + t.m_secondaryFrequencyHz) * pseudoTime) *
qCos(M_PI * (t.m_frequencyHz - t.m_secondaryFrequencyHz) * pseudoTime);
double amplitude = 0; // silence
if (t.m_frequencyHz > 10)
{
amplitude = t.m_secondaryFrequencyHz == 0 ?
qSin(2 * M_PI * t.m_frequencyHz * pseudoTime) :
qSin(M_PI * (t.m_frequencyHz + t.m_secondaryFrequencyHz) * pseudoTime) *
qCos(M_PI * (t.m_frequencyHz - t.m_secondaryFrequencyHz) * pseudoTime);
}
// the combination of two frequencies actually would have 2*amplitude,
// but I have to normalize with amplitude -1 -> +1
@@ -186,4 +194,18 @@ namespace BlackSound
audioOutput->start(generator);
}
void CSoundGenerator::playSelcal(qint32 volume, const BlackMisc::Aviation::CSelcal &selcal, QAudioDeviceInfo device)
{
if (volume < 1) return;
if (!selcal.isValid()) return;
QList<CFrequency> frequencies = selcal.getFrequencies();
Q_ASSERT(frequencies.size() == 4);
Tone t1(frequencies.at(0).value(CFrequencyUnit::Hz()), frequencies.at(1).value(CFrequencyUnit::Hz()), 1000);
Tone t2(0, 200);
Tone t3(frequencies.at(2).value(CFrequencyUnit::Hz()), frequencies.at(3).value(CFrequencyUnit::Hz()), 1000);
QList<CSoundGenerator::Tone> tones;
tones << t1 << t2 << t3;
CSoundGenerator::playSignal(volume, tones, device);
}
} // namespace