Merge branch 'f4exb:master' into freq_scanner

plugins/channelrx/demodssb/ssbdemodsink.cpp

@@ -69,10 +69,12 @@ SSBDemodSink::SSBDemodSink() :
     m_demodBufferFill = 0;
 
 	m_usb = true;
-	m_magsq = 0.0f;
+	m_magsq = 0.0;
-	m_magsqSum = 0.0f;
+	m_magsqSum = 0.0;
-	m_magsqPeak = 0.0f;
+	m_magsqPeak = 0.0;
 	m_magsqCount = 0;
+    m_magsqCur = 0.0;
+    m_magsqPrev = 0.0;
 
 	m_agc.setClampMax(SDR_RX_SCALED/100.0);
 	m_agc.setClamping(m_agcClamping);
@@ -170,10 +172,24 @@ void SSBDemodSink::processOneSample(Complex &ci)
             m_sum.imag(0.0);
         }
 
-        float agcVal = m_agcActive ? m_agc.feedAndGetValue(sideband[i]) : 0.1;
+        float agcVal = m_agcActive ? m_agc.feedAndGetValue(sideband[i]) : 1.0;
         fftfilt::cmplx& delayedSample = m_squelchDelayLine.readBack(m_agc.getStepDownDelay());
         m_audioActive = delayedSample.real() != 0.0;
-        m_squelchDelayLine.write(sideband[i]*agcVal);
+        m_magsqCur = std::norm(sideband[i]*agcVal);
+
+        // Prevent overload if squared magnitude variation is 90% full scale (0.9*.0.9 = 0.81)
+        // Only if AGC is active
+        if (m_agcActive && (m_magsqCur - m_magsqPrev > m_agcTarget*m_agcTarget*8.1))
+        {
+            m_agc.reset(m_agcTarget*100.0); // Quench AGC at -20dB the target
+            m_squelchDelayLine.write(sideband[i]);
+        }
+        else
+        {
+            m_squelchDelayLine.write(sideband[i]*agcVal);
+        }
+
+        m_magsqPrev = m_magsqCur;
 
         if (m_audioMute)
         {

plugins/channelrx/demodssb/ssbdemodsink.h

@@ -101,6 +101,8 @@ private:
 	double m_magsqSum;
 	double m_magsqPeak;
     int  m_magsqCount;
+    double m_magsqCur;
+    double m_magsqPrev;
     MagSqLevelsStore m_magSqLevelStore;
     MagAGC m_agc;
     bool m_agcActive;

sdrbase/dsp/agc.h

@@ -32,6 +32,7 @@ public:
 	void setOrder(double R) { m_R = R; }
 	Real getValue();
 	Real getAverage();
+    void reset(double R) { m_moving_average.fill(R); }
 	virtual void feed(Complex& ci) = 0;
 
 protected:

sdrbase/dsp/projector.cpp

@@ -60,6 +60,15 @@ Real Projector::run(const Sample& s)
             v = re*re + im*im;
         }
             break;
+        case ProjectionDMagSq:
+        {
+            Real re = s.m_real / SDR_RX_SCALEF;
+            Real im = s.m_imag / SDR_RX_SCALEF;
+            Real curMagSq = re*re + im*im;
+            v = curMagSq - m_prevVal;
+            m_prevVal = curMagSq;
+        }
+            break;
         case ProjectionMagDB:
         {
             Real re = s.m_real / SDR_RX_SCALEF;
@@ -235,6 +244,13 @@ Real Projector::run(const std::complex<float>& s)
         case ProjectionMagSq:
             v = std::norm(s);
             break;
+        case ProjectionDMagSq:
+        {
+            Real curMagSq = std::norm(s);
+            v = curMagSq - m_prevVal;
+            m_prevVal = curMagSq;
+        }
+            break;
         case ProjectionMagDB:
         {
             Real magsq = std::norm(s);

sdrbase/dsp/projector.h

@@ -33,6 +33,7 @@ public:
         ProjectionImag,     //!< Extract imaginary part
         ProjectionMagLin,   //!< Calculate linear magnitude or modulus
         ProjectionMagSq,    //!< Calculate linear squared magnitude or power
+        ProjectionDMagSq,   //!< Calculate time derivative of linear squared magnitude or power
         ProjectionMagDB,    //!< Calculate logarithmic (dB) of squared magnitude
         ProjectionPhase,    //!< Calculate phase
         ProjectionDOAP,     //!< Calculate ambiguous DOA from phase as phase difference (assuming positive)
@@ -60,6 +61,7 @@ private:
     static Real normalizeAngle(Real angle);
     ProjectionType m_projectionType;
     Real m_prevArg;
+    Real m_prevVal;
     Real *m_cache;
     bool m_cacheMaster;
 };

sdrgui/gui/glscope.cpp

@@ -1893,6 +1893,7 @@ void GLScope::setYScale(ScaleEngine &scale, uint32_t highlightedTraceIndex)
         break;
     case Projector::ProjectionMagLin:
     case Projector::ProjectionMagSq:
+    case Projector::ProjectionDMagSq:
         if (amp_range < 1e-9) {
             scale.setRange(Unit::None, amp_ofs * 1e12, amp_range * 1e12 + amp_ofs * 1e12);
         } else if (amp_range < 1e-6) {

sdrgui/gui/glscopegui.cpp

@@ -1315,6 +1315,7 @@ void GLScopeGUI::fillProjectionCombo(QComboBox* comboBox)
     comboBox->addItem("Imag", Projector::ProjectionImag);
     comboBox->addItem("Mag", Projector::ProjectionMagLin);
     comboBox->addItem("MagSq", Projector::ProjectionMagSq);
+    comboBox->addItem("dMagSq", Projector::ProjectionDMagSq);
     comboBox->addItem("MagdB", Projector::ProjectionMagDB);
     comboBox->addItem("Phi", Projector::ProjectionPhase);
     comboBox->addItem("DOAP", Projector::ProjectionDOAP);