Changed AGC to enhanced NFM squelch

include-gpl/dsp/agc.h

@@ -71,7 +71,121 @@ private:
 	Real m_fill;    // refill average at this level
 	Real m_cutoff;  // consider samples only above this level
 	Real m_clip;    // never go below this level
-	MovingAverage m_moving_average; // Averaging engine. The stack length conditions the smoothness of AGC.
+	MovingAverage<Real> m_moving_average; // Averaging engine. The stack length conditions the smoothness of AGC.
+};
+
+
+class EvenSimplerAGC
+{
+public:
+
+	EvenSimplerAGC() :
+		m_u0(1.0),
+		m_R(1.0),
+		m_moving_average()
+	{}
+
+	EvenSimplerAGC(int historySize, Real R) :
+		m_u0(1.0),
+		m_R(R),
+		m_moving_average(historySize, m_R)
+	{}
+
+	void resize(int historySize, Real R)
+	{
+		m_R = R;
+		m_moving_average.resize(historySize, R);
+	}
+
+	Real getValue()
+	{
+		return m_u0;
+	}
+
+	void feed(Complex& ci)
+	{
+		ci *= m_u0;
+		Real magsq = ci.real()*ci.real() + ci.imag()*ci.imag();
+		m_moving_average.feed(magsq);
+		m_u0 = m_R / m_moving_average.average();
+	}
+
+	void close()
+	{
+		m_moving_average.fill(m_R);
+		m_u0 = 1.0;
+	}
+
+private:
+	Real m_u0;
+	Real m_R;       // objective magsq
+	MovingAverage<Real> m_moving_average; // Averaging engine. The stack length conditions the smoothness of AGC.
+};
+
+class AlphaAGC
+{
+public:
+
+	AlphaAGC() :
+		m_u0(1.0),
+		m_R(1.0),
+		m_alpha(0.1),
+		m_squelch(false),
+		m_moving_average()
+	{}
+
+	AlphaAGC(int historySize, Real R, Real alpha) :
+		m_u0(1.0),
+		m_R(R),
+		m_alpha(alpha),
+		m_squelch(false),
+		m_moving_average(historySize, m_R)
+	{}
+
+	void resize(int historySize, Real R, Real alpha)
+	{
+		m_R = R;
+		m_alpha = alpha;
+		m_squelch = false;
+		m_moving_average.resize(historySize, R);
+	}
+
+	Real getValue()
+	{
+		return m_u0;
+	}
+
+	void feed(Complex& ci)
+	{
+		ci *= m_u0;
+		Real magsq = ci.real()*ci.real() + ci.imag()*ci.imag();
+
+		if (m_squelch && (magsq < m_moving_average.average()))
+		{
+			m_moving_average.feed(m_moving_average.average() - m_alpha*(m_moving_average.average() - magsq));
+		}
+		else
+		{
+			m_squelch = true;
+			m_moving_average.feed(magsq);
+		}
+
+		m_u0 = m_R / m_moving_average.average();
+	}
+
+	void close()
+	{
+		m_moving_average.fill(m_R);
+		m_u0 = 1.0;
+		m_squelch = false;
+	}
+
+private:
+	Real m_u0;
+	Real m_R;       // objective magsq
+	Real m_alpha;
+	bool m_squelch;
+	MovingAverage<Real> m_moving_average; // Averaging engine. The stack length conditions the smoothness of AGC.
 };
 
 

include-gpl/dsp/movingaverage.h

@@ -4,7 +4,7 @@
 #include <vector>
 #include "dsp/dsptypes.h"
 
-class MovingAverage {
+template<class Type> class MovingAverage {
 public:
 	MovingAverage() :
 		m_history(),
@@ -13,23 +13,23 @@ public:
 	{
 	}
 
-	MovingAverage(int historySize, Real initial) :
+	MovingAverage(int historySize, Type initial) :
 		m_history(historySize, initial),
-		m_sum(historySize * initial),
+		m_sum((float) historySize * initial),
 		m_ptr(0)
 	{
 	}
 
-	void resize(int historySize, Real initial)
+	void resize(int historySize, Type initial)
 	{
 		m_history.resize(historySize);
 		for(size_t i = 0; i < m_history.size(); i++)
 			m_history[i] = initial;
-		m_sum = m_history.size() * initial;
+		m_sum = (float) m_history.size() * initial;
 		m_ptr = 0;
 	}
 
-	void feed(Real value)
+	void feed(Type value)
 	{
 		m_sum -= m_history[m_ptr];
 		m_history[m_ptr] = value;
@@ -39,21 +39,21 @@ public:
 			m_ptr = 0;
 	}
 
-	void fill(Real value)
+	void fill(Type value)
 	{
 		for(size_t i = 0; i < m_history.size(); i++)
 			m_history[i] = value;
-		m_sum = m_history.size() * value;
+		m_sum = (float) m_history.size() * value;
 	}
 
-	Real average() const
+	Type average() const
 	{
-		return m_sum / (Real)m_history.size();
+		return m_sum / (float) m_history.size();
 	}
 
 protected:
-	std::vector<Real> m_history;
+	std::vector<Type> m_history;
-	Real m_sum;
+	Type m_sum;
 	uint m_ptr;
 };
 

plugins/channel/am/amdemod.h

@@ -117,7 +117,7 @@ private:
 
 	Real m_lastArgument;
 	Complex m_lastSample;
-	MovingAverage m_movingAverage;
+	MovingAverage<Real> m_movingAverage;
 	SimpleAGC m_volumeAGC;
 
 	AudioVector m_audioBuffer;

plugins/channel/nfm/nfmdemod.cpp

@@ -26,7 +26,7 @@
 
 #include <iostream>
 
-static const Real afSqTones[2] = {2000.0, 8000.0};
+static const Real afSqTones[2] = {1200.0, 8000.0};
 
 MESSAGE_CLASS_DEFINITION(NFMDemod::MsgConfigureNFMDemod, Message)
 
@@ -53,10 +53,11 @@ NFMDemod::NFMDemod(AudioFifo* audioFifo, SampleSink* sampleSink) :
 
 	m_movingAverage.resize(16, 0);
 	m_agcLevel = 0.003;
-	m_AGC.resize(4096, m_agcLevel, 0, 0.1*m_agcLevel);
+	//m_AGC.resize(480, m_agcLevel, 0, 0.1*m_agcLevel);
+	m_AGC.resize(240, m_agcLevel*m_agcLevel, 0.1);
 
 	m_ctcssDetector.setCoefficients(3000, 6000.0); // 0.5s / 2 Hz resolution
-	m_afSquelch.setCoefficients(24, 48000.0, 1, 1); // 4000 Hz span, 250us
+	m_afSquelch.setCoefficients(24, 48000.0, 5, 1); // 4000 Hz span, 250us
 	m_afSquelch.setThreshold(0.001);
 }
 
@@ -117,8 +118,10 @@ void NFMDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iter
 
 				qint16 sample;
 
-				m_AGC.feed(abs(ci));
+				//m_AGC.feed(abs(ci));
-				ci *= (m_agcLevel / m_AGC.getValue());
+				//ci *= (m_agcLevel / m_AGC.getValue());
+
+				m_AGC.feed(ci);
 
 				// demod
 				/*

plugins/channel/nfm/nfmdemod.h

@@ -145,8 +145,8 @@ private:
 	Real m_lastArgument;
 	Complex m_m1Sample;
 	Complex m_m2Sample;
-	MovingAverage m_movingAverage;
+	MovingAverage<Real> m_movingAverage;
-	SimpleAGC m_AGC;
+	AlphaAGC m_AGC;
 	Real m_agcLevel; // AGC will aim to  this level
 	Real m_agcFloor; // AGC will not go below this level
 

plugins/channel/wfm/wfmdemod.h

@@ -122,7 +122,7 @@ private:
 	Real m_lastArgument;
 	Complex m_m1Sample; // x^-1 sample
 	Complex m_m2Sample; // x^-1 sample
-	MovingAverage m_movingAverage;
+	MovingAverage<Real> m_movingAverage;
 
 	AudioVector m_audioBuffer;
 	uint m_audioBufferFill;

sdrbase/dsp/afsquelch.cpp

@@ -189,7 +189,7 @@ void AFSquelch::evaluate()
 
 	if (open)
 	{
-		if (attackCount < samplesAttack)
+		if (samplesAttack && (attackCount < samplesAttack))
 		{
 			attackCount++;
 		}
@@ -201,7 +201,7 @@ void AFSquelch::evaluate()
 	}
 	else
 	{
-		if (decayCount < samplesDecay)
+		if (samplesDecay && (decayCount < samplesDecay))
 		{
 			decayCount++;
 		}