ATV Demod: implement NCO and interpolator change

plugins/channelrx/demodatv/atvdemod.cpp

@@ -63,6 +63,7 @@ ATVDemod::ATVDemod() :
     m_intSynchroPoints=0;
     m_intNumberOfLines=0;
     m_intNumberOfRowsToDisplay=0;
+    m_intTVSampleRate = 0;
 
     m_objMagSqAverage.resize(32, 1.0);
 
@@ -190,7 +191,10 @@ void ATVDemod::feed(const SampleVector::const_iterator& begin, const SampleVecto
         fltI = it->real();
         fltQ = it->imag();
 #endif
-
+        if (m_objRFRunning.m_intFrequencyOffset != 0)
+        {
+            m_nco.nextIQMul(fltI, fltQ);
+        }
 
         //********** demodulation **********
 
@@ -494,9 +498,11 @@ bool ATVDemod::handleMessage(const Message& cmd)
     {
         DownChannelizer::MsgChannelizerNotification& objNotif = (DownChannelizer::MsgChannelizerNotification&) cmd;
         m_objConfig.m_intSampleRate = objNotif.getSampleRate();
+        m_objRFConfig.m_intFrequencyOffset = objNotif.getFrequencyOffset();
 
         qDebug() << "ATVDemod::handleMessage: MsgChannelizerNotification:"
-                << " m_intMsps: " << m_objConfig.m_intSampleRate;
+                << " m_intSampleRate: " << m_objConfig.m_intSampleRate
+                << " m_intFrequencyOffset: " << m_objRFConfig.m_intFrequencyOffset;
 
         applySettings();
 
@@ -553,6 +559,32 @@ void ATVDemod::applySettings()
         return;
     }
 
+    if((m_objRFConfig.m_intFrequencyOffset != m_objRFRunning.m_intFrequencyOffset) ||
+        (m_objConfig.m_intSampleRate != m_objRunning.m_intSampleRate))
+    {
+        m_nco.setFreq(-m_objRFConfig.m_intFrequencyOffset, m_objConfig.m_intSampleRate);
+    }
+
+    if ((m_objConfig.m_intSampleRate != m_objRunning.m_intSampleRate)
+        || (m_objRFConfig.m_fltRFBandwidth != m_objRFRunning.m_fltRFBandwidth))
+    {
+        m_intTVSampleRate = (m_objConfig.m_intSampleRate / 1000000) * 1000000; // make sure working sample rate is a multiple of rate units
+
+        if (m_intTVSampleRate > 0)
+        {
+            m_interpolatorDistance = (Real) m_intTVSampleRate / (Real) m_objConfig.m_intSampleRate;
+        }
+        else
+        {
+            m_intTVSampleRate = m_objConfig.m_intSampleRate;
+            m_interpolatorDistanceRemain = 0;
+            m_interpolatorDistance = 1.0f;
+        }
+
+        m_interpolatorDistanceRemain = 0;
+        m_interpolator.create(48, m_intTVSampleRate, m_objRFConfig.m_fltRFBandwidth / 2.2, 3.0);
+    }
+
     if((m_objConfig.m_fltFramePerS != m_objRunning.m_fltFramePerS)
        || (m_objConfig.m_fltLineDurationUs != m_objRunning.m_fltLineDurationUs)
        || (m_objConfig.m_intSampleRate != m_objRunning.m_intSampleRate)

plugins/channelrx/demodatv/atvdemod.h

@@ -78,6 +78,7 @@ public:
 
     struct ATVRFConfig
     {
+	    int64_t       m_intFrequencyOffset;
         ATVModulation m_enmModulation;
         float         m_fltRFBandwidth;
         float         m_fltRFOppBandwidth;
@@ -85,6 +86,7 @@ public:
         bool          m_blndecimatorEnable;
 
         ATVRFConfig() :
+            m_intFrequencyOffset(0),
             m_enmModulation(ATV_FM1),
             m_fltRFBandwidth(0),
             m_fltRFOppBandwidth(0),
@@ -252,6 +254,9 @@ private:
 
     MovingAverage<double> m_objMagSqAverage;
 
+    int m_intTVSampleRate;
+    NCO m_nco;
+
     // Interpolator group for decimation and/or double sideband RF filtering
     Interpolator m_interpolator;
     Real m_interpolatorDistance;

plugins/channelrx/demodatv/atvdemodgui.cpp

@@ -296,7 +296,7 @@ ATVDemodGUI::ATVDemodGUI(PluginAPI* objPluginAPI, DeviceSourceAPI *objDeviceAPI,
     m_objChannelMarker.setCenterFrequency(0);
     m_objChannelMarker.setVisible(true);
 
-    //connect(&m_objChannelMarker, SIGNAL(changed()), this, SLOT(viewChanged()));
+    connect(&m_objChannelMarker, SIGNAL(changed()), this, SLOT(viewChanged()));
 
     m_objDeviceAPI->registerChannelInstance(m_strChannelID, this);
     m_objDeviceAPI->addChannelMarker(&m_objChannelMarker);
@@ -333,7 +333,6 @@ void ATVDemodGUI::applySettings()
         ui->deltaFrequencyMinus->setChecked(m_objChannelMarker.getCenterFrequency() < 0);
 
         m_objChannelizer->configure(m_objChannelizer->getInputMessageQueue(),
-                //m_objATVDemod->GetSampleRate(),
                 m_objChannelizer->getInputSampleRate(), // always use maximum available bandwidth
                 m_objChannelMarker.getCenterFrequency());
 
@@ -584,3 +583,23 @@ void ATVDemodGUI::on_decimator_toggled(bool checked)
     applyRFSettings();
 }
 
+void ATVDemodGUI::on_deltaFrequency_changed(quint64 value)
+{
+    if (ui->deltaFrequencyMinus->isChecked()) {
+        m_objChannelMarker.setCenterFrequency(-value);
+    } else {
+        m_objChannelMarker.setCenterFrequency(value);
+    }
+}
+
+void ATVDemodGUI::on_deltaFrequencyMinus_toggled(bool minus)
+{
+    int deltaFrequency = m_objChannelMarker.getCenterFrequency();
+    bool minusDelta = (deltaFrequency < 0);
+
+    if (minus ^ minusDelta) // sign change
+    {
+        m_objChannelMarker.setCenterFrequency(-deltaFrequency);
+    }
+}
+

plugins/channelrx/demodatv/atvdemodgui.h

@@ -76,6 +76,8 @@ private slots:
     void on_rfOppBW_valueChanged(int value);
     void on_rfFiltering_toggled(bool checked);
     void on_decimator_toggled(bool checked);
+    void on_deltaFrequency_changed(quint64 value);
+    void on_deltaFrequencyMinus_toggled(bool minus);
 
 private:
 	Ui::ATVDemodGUI* ui;

sdrbase/dsp/nco.cpp

@@ -65,6 +65,17 @@ Complex NCO::nextQI()
 	return Complex(-m_table[(m_phase + TableSize / 4) % TableSize], m_table[m_phase]);
 }
 
+void NCO::nextIQMul(Real& i, Real& q)
+{
+    nextPhase();
+    Real x = i;
+    Real y = q;
+    const Real& u = m_table[m_phase];
+    const Real& v = -m_table[(m_phase + TableSize / 4) % TableSize];
+    i = x*u - y*v;
+    q = x*v + y*u;
+}
+
 float NCO::get()
 {
 	return m_table[m_phase];

sdrbase/dsp/nco.h

@@ -52,6 +52,7 @@ public:
 	Real next();            //!< Return next real sample
 	Complex nextIQ();       //!< Return next complex sample
 	Complex nextQI();       //!< Return next complex sample (reversed)
+	void nextIQMul(Real& i, Real& q); //!< multiply I,Q separately with next sample
 	Real get();             //!< Return current real sample (no phase increment)
 	Complex getIQ();        //!< Return current complex sample (no phase increment)
 	void getIQ(Complex& c); //!< Sets to the current complex sample (no phase increment)