Tx ph.1: new AM modulator plugin (3). Implemented actual modulation code.

plugins/channeltx/modam/ammod.cpp

@@ -18,6 +18,7 @@
 
 #include <QTime>
 #include <QDebug>
+#include <QMutexLocker>
 #include <stdio.h>
 #include <complex.h>
 #include <dsp/upchannelizer.h>
@@ -35,7 +36,7 @@ AMMod::AMMod() :
 	m_config.m_inputFrequencyOffset = 0;
 	m_config.m_rfBandwidth = 12500;
 	m_config.m_afBandwidth = 3000;
-	m_config.m_modPercent = 20;
+	m_config.m_modFactor = 20;
 	m_config.m_audioSampleRate = DSPEngine::instance()->getAudioSampleRate();
 
 	apply();
@@ -46,6 +47,8 @@ AMMod::AMMod() :
 	m_movingAverage.resize(16, 0);
 	m_volumeAGC.resize(4096, 0.003, 0);
 	m_magsq = 0.0;
+
+	m_toneNco.setFreq(1000.0, m_config.m_audioSampleRate);
 }
 
 AMMod::~AMMod()
@@ -60,7 +63,30 @@ void AMMod::configure(MessageQueue* messageQueue, Real rfBandwidth, Real afBandw
 
 void AMMod::pull(Sample& sample)
 {
-	// TODO
+	Complex ci;
+
+	if (m_interpolator.interpolate(&m_interpolatorDistanceRemain, m_modSample, &ci))
+	{
+		m_settingsMutex.lock();
+		m_carrierNco.nextPhase();
+		m_toneNco.nextPhase();
+		m_settingsMutex.unlock();
+
+		m_carrierNco.getIQ(m_modSample);
+		Real t = m_toneNco.get();
+
+		m_modSample *= (t+1.0f) * m_running.m_modFactor * 16384.0f; // modulate carrier
+
+		m_interpolatorDistanceRemain += m_interpolatorDistance;
+	}
+
+	Real magsq = ci.real() * ci.real() + ci.imag() * ci.imag();
+	magsq /= (1<<30);
+	m_movingAverage.feed(magsq);
+	m_magsq = m_movingAverage.average();
+
+	sample.m_real = (FixReal) ci.real();
+	sample.m_imag = (FixReal) ci.imag();
 }
 
 void AMMod::start()
@@ -100,7 +126,7 @@ bool AMMod::handleMessage(const Message& cmd)
 
 		m_config.m_rfBandwidth = cfg.getRFBandwidth();
 		m_config.m_afBandwidth = cfg.getAFBandwidth();
-		m_config.m_modPercent = cfg.getModPercent();
+		m_config.m_modFactor = cfg.getModFactor();
 		m_config.m_audioMute = cfg.getAudioMute();
 
 		apply();
@@ -108,7 +134,7 @@ bool AMMod::handleMessage(const Message& cmd)
 		qDebug() << "AMMod::handleMessage: MsgConfigureAMMod:"
 				<< " m_rfBandwidth: " << m_config.m_rfBandwidth
 				<< " m_afBandwidth: " << m_config.m_afBandwidth
-				<< " m_modPercent: " << m_config.m_modPercent
+				<< " m_modFactor: " << m_config.m_modFactor
 				<< " m_audioMute: " << m_config.m_audioMute;
 
 		return true;
@@ -122,10 +148,9 @@ bool AMMod::handleMessage(const Message& cmd)
 void AMMod::apply()
 {
 
-	if((m_config.m_inputFrequencyOffset != m_running.m_inputFrequencyOffset) ||
+	if(m_config.m_inputFrequencyOffset != m_running.m_inputFrequencyOffset)
-		(m_config.m_outputSampleRate != m_running.m_outputSampleRate))
 	{
-		m_carrierNco.setFreq(-m_config.m_inputFrequencyOffset, m_config.m_outputSampleRate);
+		m_carrierNco.setFreq(-m_config.m_inputFrequencyOffset, m_config.m_audioSampleRate);
 	}
 
 	if((m_config.m_outputSampleRate != m_running.m_outputSampleRate) ||
@@ -150,7 +175,7 @@ void AMMod::apply()
 	m_running.m_inputFrequencyOffset = m_config.m_inputFrequencyOffset;
 	m_running.m_rfBandwidth = m_config.m_rfBandwidth;
 	m_running.m_afBandwidth = m_config.m_afBandwidth;
-	m_running.m_modPercent = m_config.m_modPercent;
+	m_running.m_modFactor = m_config.m_modFactor;
 	m_running.m_audioSampleRate = m_config.m_audioSampleRate;
 	m_running.m_audioMute = m_config.m_audioMute;
 }

plugins/channeltx/modam/ammod.h

@@ -51,7 +51,7 @@ private:
     public:
         Real getRFBandwidth() const { return m_rfBandwidth; }
         Real getAFBandwidth() const { return m_afBandwidth; }
-        Real getModPercent() const { return m_modPercent; }
+        float getModFactor() const { return m_modFactor; }
         bool getAudioMute() const { return m_audioMute; }
 
         static MsgConfigureAMMod* create(Real rfBandwidth, Real afBandwidth, int modPercent, bool audioMute)
@@ -62,14 +62,14 @@ private:
     private:
         Real m_rfBandwidth;
         Real m_afBandwidth;
-        Real m_modPercent;
+        float m_modFactor;
         bool m_audioMute;
 
-        MsgConfigureAMMod(Real rfBandwidth, Real afBandwidth, int modPercent, bool audioMute) :
+        MsgConfigureAMMod(Real rfBandwidth, Real afBandwidth, float modFactor, bool audioMute) :
             Message(),
             m_rfBandwidth(rfBandwidth),
             m_afBandwidth(afBandwidth),
-            m_modPercent(modPercent),
+            m_modFactor(modFactor),
             m_audioMute(audioMute)
         { }
     };
@@ -90,7 +90,7 @@ private:
         qint64 m_inputFrequencyOffset;
         Real m_rfBandwidth;
         Real m_afBandwidth;
-        int m_modPercent;
+        float m_modFactor;
         quint32 m_audioSampleRate;
         bool m_audioMute;
 
@@ -99,7 +99,7 @@ private:
             m_inputFrequencyOffset(0),
             m_rfBandwidth(-1),
             m_afBandwidth(-1),
-            m_modPercent(20),
+            m_modFactor(0.2f),
             m_audioSampleRate(0),
             m_audioMute(false)
         { }
@@ -110,6 +110,7 @@ private:
 
     NCO m_carrierNco;
     NCO m_toneNco;
+    Complex m_modSample;
     Interpolator m_interpolator;
     Real m_interpolatorDistance;
     Real m_interpolatorDistanceRemain;

plugins/channeltx/modam/ammodgui.cpp

@@ -278,7 +278,7 @@ void AMModGUI::applySettings()
 		m_amMod->configure(m_amMod->getInputMessageQueue(),
 			m_rfBW[ui->rfBW->value()],
 			ui->afBW->value() * 1000.0,
-			ui->modPercent->value(),
+			ui->modPercent->value() / 100.0f,
 			ui->audioMute->isChecked());
 	}
 }

sdrbase/dsp/nco.cpp

@@ -49,22 +49,28 @@ void NCO::setFreq(Real freq, Real sampleRate)
 
 float NCO::next()
 {
-	m_phase += m_phaseIncrement;
+	nextPhase();
-	while(m_phase >= TableSize)
-		m_phase -= TableSize;
-	while(m_phase < 0)
-		m_phase += TableSize;
-
 	return m_table[m_phase];
 }
 
 Complex NCO::nextIQ()
 {
-	m_phase += m_phaseIncrement;
+	nextPhase();
-	while(m_phase >= TableSize)
-		m_phase -= TableSize;
-	while(m_phase < 0)
-		m_phase += TableSize;
-
 	return Complex(m_table[m_phase], -m_table[(m_phase + TableSize / 4) % TableSize]);
 }
+
+float NCO::get()
+{
+	return m_table[m_phase];
+}
+
+Complex NCO::getIQ()
+{
+	return Complex(m_table[m_phase], -m_table[(m_phase + TableSize / 4) % TableSize]);
+}
+
+void NCO::getIQ(Complex& c)
+{
+	c.real(m_table[m_phase]);
+	c.imag(-m_table[(m_phase + TableSize / 4) % TableSize]);
+}

sdrbase/dsp/nco.h

@@ -38,8 +38,21 @@ public:
 	NCO();
 
 	void setFreq(Real freq, Real sampleRate);
-	Real next();
+
-	Complex nextIQ();
+	void nextPhase()        //!< Increment phase
+	{
+		m_phase += m_phaseIncrement;
+		while(m_phase >= TableSize)
+			m_phase -= TableSize;
+		while(m_phase < 0)
+			m_phase += TableSize;
+	}
+
+	Real next();            //!< Return next real sample
+	Complex nextIQ();       //!< Return next complex 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)
 };
 
 #endif // INCLUDE_NCO_H