SSB demod: implement audio mute button squelch light indicator

plugins/channelrx/demodssb/ssbdemod.cpp

@@ -38,6 +38,7 @@ SSBDemod::SSBDemod(BasebandSampleSink* sampleSink) :
     m_agcNbSamples(12000),
     m_agcPowerThreshold(1e-2),
     m_agcThresholdGate(0),
+    m_audioActive(false),
     m_sampleSink(sampleSink),
     m_audioFifo(4, 24000),
     m_settingsMutex(QMutex::Recursive)
@@ -181,6 +182,9 @@ void SSBDemod::feed(const SampleVector::const_iterator& begin, const SampleVecto
                 m_sum.imag(0.0);
 			}
 
+            double agcVal = m_agcActive ? m_agc.feedAndGetValue(sideband[i]) : 1.0;
+            m_audioActive = agcVal != 0.0;
+
 			if (m_audioMute)
 			{
 				m_audioBuffer[m_audioBufferFill].r = 0;
@@ -188,8 +192,6 @@ void SSBDemod::feed(const SampleVector::const_iterator& begin, const SampleVecto
 			}
 			else
 			{
-			    double agcVal = m_agcActive ? m_agc.feedAndGetValue(sideband[i]) : 1.0;
-
 				if (m_audioBinaual)
 				{
 					if (m_audioFlipChannels)

plugins/channelrx/demodssb/ssbdemod.h

@@ -56,6 +56,7 @@ public:
 	virtual bool handleMessage(const Message& cmd);
 
 	double getMagSq() const { return m_magsq; }
+	bool getAudioActive() const { return m_audioActive; }
 
     void getMagSqLevels(double& avg, double& peak, int& nbSamples)
     {
@@ -185,6 +186,7 @@ private:
     int m_agcNbSamples;         //!< number of audio (48 kHz) samples for AGC averaging
     double m_agcPowerThreshold; //!< AGC power threshold (linear)
     int m_agcThresholdGate;     //!< Gate length in number of samples befor threshold triggers
+    bool m_audioActive;         //!< True if an audio signal is produced (no AGC or AGC and above threshold)
 
 	NCOF m_nco;
 	Interpolator m_interpolator;

plugins/channelrx/demodssb/ssbdemodgui.cpp

@@ -357,7 +357,8 @@ SSBDemodGUI::SSBDemodGUI(PluginAPI* pluginAPI, DeviceSourceAPI *deviceAPI, QWidg
 	m_audioFlipChannels(false),
 	m_dsb(false),
     m_audioMute(false),
-	m_channelPowerDbAvg(20,0)
+	m_channelPowerDbAvg(20,0),
+	m_squelchOpen(false)
 {
 	ui->setupUi(this);
 	setAttribute(Qt::WA_DeleteOnClose, true);
@@ -549,4 +550,17 @@ void SSBDemodGUI::tick()
             nbMagsqSamples);
 
     ui->channelPower->setText(tr("%1 dB").arg(powDbAvg, 0, 'f', 1));
+
+    bool squelchOpen = m_ssbDemod->getAudioActive();
+
+    if (squelchOpen != m_squelchOpen)
+    {
+        if (squelchOpen) {
+            ui->audioMute->setStyleSheet("QToolButton { background-color : green; }");
+        } else {
+            ui->audioMute->setStyleSheet("QToolButton { background:rgb(79,79,79); }");
+        }
+
+        m_squelchOpen = squelchOpen;
+    }
 }

plugins/channelrx/demodssb/ssbdemodgui.h

@@ -72,6 +72,7 @@ private:
 	bool m_dsb;
 	bool m_audioMute;
 	MovingAverage<double> m_channelPowerDbAvg;
+	bool m_squelchOpen;
 
 	ThreadedBasebandSampleSink* m_threadedChannelizer;
 	DownChannelizer* m_channelizer;

plugins/channelrx/demodssb/ssbdemodgui.ui

@@ -521,7 +521,7 @@
          </size>
         </property>
         <property name="toolTip">
-         <string>AGC power threshold (dB)</string>
+         <string>Power threshold (dB)</string>
         </property>
         <property name="minimum">
          <number>-99</number>
@@ -546,7 +546,7 @@
          </size>
         </property>
         <property name="toolTip">
-         <string>AGC power threshold (dB)</string>
+         <string>Power threshold (dB)</string>
         </property>
         <property name="text">
          <string>-00</string>
@@ -565,7 +565,7 @@
          </size>
         </property>
         <property name="toolTip">
-         <string>Set threshiold gate (ms)</string>
+         <string>Power threshiold gate (ms)</string>
         </property>
         <property name="maximum">
          <number>20</number>
@@ -587,7 +587,7 @@
          </size>
         </property>
         <property name="toolTip">
-         <string>Threshiold gate (ms)</string>
+         <string>Power threshiold gate (ms)</string>
         </property>
         <property name="text">
          <string>00</string>