SSB demod: clamp AGC value

plugins/channelrx/demodssb/ssbdemod.cpp

@@ -68,6 +68,9 @@ SSBDemod::SSBDemod(BasebandSampleSink* sampleSink) :
 	m_magsqPeak = 0.0f;
 	m_magsqCount = 0;
 
+	m_agc.setClampMax(32768.0*32768.0);
+	m_agc.setClamping(true);
+
 	SSBFilter = new fftfilt(m_LowCutoff / m_audioSampleRate, m_Bandwidth / m_audioSampleRate, ssbFftLen);
 	DSBFilter = new fftfilt((2.0f * m_Bandwidth) / m_audioSampleRate, 2 * ssbFftLen);
 

sdrbase/dsp/agc.cpp

@@ -71,12 +71,14 @@ void MagAGC::resize(int historySize, Real R)
     m_stepUpCounter = 0;
     m_stepDownCounter = m_stepLength;
     AGC::resize(historySize, R);
+    m_moving_average.fill(0);
 }
 
 void MagAGC::setOrder(double R)
 {
     m_R2 = R*R;
     AGC::setOrder(R);
+    m_moving_average.fill(0);
 }
 
 void MagAGC::setThresholdEnable(bool enable)
@@ -110,7 +112,7 @@ double MagAGC::feedAndGetValue(const Complex& ci)
         else
         {
             double u02 = m_R2 / m_moving_average.average();
-            m_u0 = (u02 * m_magsq > m_clampMax) ? m_clampMax / sqrt(m_magsq) : sqrt(u02);
+            m_u0 = (u02 * m_magsq > m_clampMax) ? sqrt(m_clampMax / m_magsq) : sqrt(u02);
         }
     }
     else

sdrbase/dsp/agc.h

@@ -24,7 +24,7 @@ public:
 
 protected:
 	double m_u0;                            //!< AGC factor
-	double m_R;                             //!< objective mag
+	double m_R;                             //!< ordered magnitude
 	MovingAverage<double> m_moving_average; //!< Averaging engine. The stack length conditions the smoothness of AGC.
 	int m_historySize;                      //!< Averaging length (attack)
 	int m_count;                            //!< Samples counter
@@ -61,8 +61,8 @@ private:
     int m_gateCounter;     //!< threshold gate samples counter
     int m_stepDownDelay;   //!< delay in samples before cutoff (release)
     bool m_clamping;       //!< clamping active
-    double m_R2;           //!< square of objective magnitude
-    double m_clampMax;     //!< maximum to clamp to
+    double m_R2;           //!< square of ordered magnitude
+    double m_clampMax;     //!< maximum to clamp to as power value
 };