UDP source plugin: implemented AM with DC filtering and AGC

plugins/channelrx/udpsrc/udpsrc.cpp

@@ -32,11 +32,13 @@ MESSAGE_CLASS_DEFINITION(UDPSrc::MsgUDPSrcSpectrum, Message)
 UDPSrc::UDPSrc(MessageQueue* uiMessageQueue, UDPSrcGUI* udpSrcGUI, BasebandSampleSink* spectrum) :
     m_outMovingAverage(480, 1e-10),
     m_inMovingAverage(480, 1e-10),
+    m_amMovingAverage(480, 1e-10),
     m_audioFifo(4, 24000),
     m_squelchOpen(false),
     m_squelchOpenCount(0),
     m_squelchCloseCount(0),
     m_squelchThreshold(4800),
+    m_agc(12000, m_agcTarget, 1e-6),
     m_settingsMutex(QMutex::Recursive)
 {
 	setObjectName("UDPSrc");
@@ -78,6 +80,9 @@ UDPSrc::UDPSrc(MessageQueue* uiMessageQueue, UDPSrcGUI* udpSrcGUI, BasebandSampl
 		qWarning("UDPSrc::UDPSrc: cannot bind audio port");
 	}
 
+    m_agc.setClampMax(32768.0*32768.0);
+    m_agc.setClamping(true);
+
 	//DSPEngine::instance()->addAudioSink(&m_audioFifo);
 }
 
@@ -122,6 +127,7 @@ void UDPSrc::configureImmediate(MessageQueue* messageQueue,
 		Real squelchDB,
 		Real squelchGate,
 		bool squelchEnabled,
+		bool agc,
 		bool force)
 {
 	Message* cmd = MsgUDPSrcConfigureImmediate::create(
@@ -132,6 +138,7 @@ void UDPSrc::configureImmediate(MessageQueue* messageQueue,
 			squelchDB,
 			squelchGate,
 			squelchEnabled,
+			agc,
 			force);
 	messageQueue->push(cmd);
 }
@@ -158,7 +165,21 @@ void UDPSrc::feed(const SampleVector::const_iterator& begin, const SampleVector:
 
 		if(m_interpolator.decimate(&m_sampleDistanceRemain, c, &ci))
 		{
-		    double inMagSq = ci.real()*ci.real() + ci.imag()*ci.imag();
+		    double inMagSq;
+		    double agcFactor = 1.0;
+
+            if ((m_running.m_agc) &&
+                (m_running.m_sampleFormat != FormatNFM) &&
+                (m_running.m_sampleFormat != FormatNFMMono) &&
+                (m_running.m_sampleFormat != FormatS16LE))
+            {
+                agcFactor = m_agc.feedAndGetValue(ci);
+                inMagSq = m_agc.getMagSq();
+            }
+            else
+            {
+                inMagSq = ci.real()*ci.real() + ci.imag()*ci.imag();
+            }
 
 		    m_inMovingAverage.feed(inMagSq / (1<<30));
 		    m_inMagsq = m_inMovingAverage.average();
@@ -172,6 +193,7 @@ void UDPSrc::feed(const SampleVector::const_iterator& begin, const SampleVector:
 
 			if (m_running.m_sampleFormat == FormatLSB) // binaural LSB
 			{
+			    ci *= agcFactor;
 				int n_out = UDPFilter->runSSB(ci, &sideband, false);
 
 				if (n_out)
@@ -187,6 +209,7 @@ void UDPSrc::feed(const SampleVector::const_iterator& begin, const SampleVector:
 			}
 			if (m_running.m_sampleFormat == FormatUSB) // binaural USB
 			{
+			    ci *= agcFactor;
 				int n_out = UDPFilter->runSSB(ci, &sideband, true);
 
 				if (n_out)
@@ -214,6 +237,7 @@ void UDPSrc::feed(const SampleVector::const_iterator& begin, const SampleVector:
 			}
 			else if (m_running.m_sampleFormat == FormatLSBMono) // Monaural LSB
 			{
+			    ci *= agcFactor;
 				int n_out = UDPFilter->runSSB(ci, &sideband, false);
 
 				if (n_out)
@@ -228,6 +252,7 @@ void UDPSrc::feed(const SampleVector::const_iterator& begin, const SampleVector:
 			}
 			else if (m_running.m_sampleFormat == FormatUSBMono) // Monaural USB
 			{
+			    ci *= agcFactor;
 				int n_out = UDPFilter->runSSB(ci, &sideband, true);
 
 				if (n_out)
@@ -242,10 +267,26 @@ void UDPSrc::feed(const SampleVector::const_iterator& begin, const SampleVector:
 			}
 			else if (m_running.m_sampleFormat == FormatAMMono)
 			{
-				FixReal demod = m_squelchOpen ? (FixReal) (sqrt(inMagSq) * m_running.m_gain) : 0;
+				FixReal demod = m_squelchOpen ? (FixReal) (sqrt(inMagSq) * agcFactor * m_running.m_gain) : 0;
 				m_udpBufferMono->write(demod);
-				m_outMovingAverage.feed((demod * demod) / (1<<30));
+				m_outMovingAverage.feed((demod * demod) / 1073741824.0);
 			}
+            else if (m_running.m_sampleFormat == FormatAMNoDCMono)
+            {
+                m_amMovingAverage.feed(inMagSq);
+
+                if (m_squelchOpen)
+                {
+                    FixReal demod = (FixReal) ((sqrt(inMagSq) - sqrt(m_amMovingAverage.average())) * agcFactor * m_running.m_gain);
+                    m_udpBufferMono->write(demod);
+                    m_outMovingAverage.feed((demod * demod) / 1073741824.0);
+                }
+                else
+                {
+                    m_udpBufferMono->write(0);
+                    m_outMovingAverage.feed(0);
+                }
+            }
 			else // Raw I/Q samples
 			{
 			    if (m_squelchOpen)
@@ -314,6 +355,7 @@ bool UDPSrc::handleMessage(const Message& cmd)
 		m_config.m_squelch = CalcDb::powerFromdB(cfg.getSquelchDB());
 		m_config.m_squelchGate = cfg.getSquelchGate();
 		m_config.m_squelchEnabled = cfg.getSquelchEnabled();
+		m_config.m_agc = cfg.getAGC();
 
 		apply(cfg.getForce());
 
@@ -324,7 +366,8 @@ bool UDPSrc::handleMessage(const Message& cmd)
 				<< " m_squelchEnabled: " << m_config.m_squelchEnabled
                 << " m_squelch: " << m_config.m_squelch
                 << " getSquelchDB: " << cfg.getSquelchDB()
-                << " m_squelchGate" << m_config.m_squelchGate;
+                << " m_squelchGate" << m_config.m_squelchGate
+                << " m_agc" << m_config.m_agc;
 
 		return true;
 
@@ -388,10 +431,16 @@ void UDPSrc::apply(bool force)
         m_interpolator.create(16, m_config.m_inputSampleRate, m_config.m_rfBandwidth / 2.0);
         m_sampleDistanceRemain = m_config.m_inputSampleRate / m_config.m_outputSampleRate;
 
-        m_squelchThreshold = m_config.m_outputSampleRate * m_config.m_squelchGate;
+        int gateNbSamples = m_config.m_inputSampleRate * m_config.m_squelchGate;
+        int agcTimeNbSamples = m_config.m_inputSampleRate * 0.2; // Fixed 200 ms
+        m_squelchThreshold = gateNbSamples;
         initSquelch(m_squelchOpen);
+        m_agc.resize(agcTimeNbSamples, m_agcTarget);
+        m_agc.setStepDownDelay(gateNbSamples);
+        m_agc.setGate(gateNbSamples);
 
-        m_inMovingAverage.resize(m_config.m_outputSampleRate * 0.01, 1e-10);  // 10 ms
+        m_inMovingAverage.resize(m_config.m_inputSampleRate * 0.01, 1e-10);   // 10 ms
+        m_amMovingAverage.resize(m_config.m_inputSampleRate * 0.01, 1e-10);   // 10 ms
         m_outMovingAverage.resize(m_config.m_outputSampleRate * 0.01, 1e-10); // 10 ms
     }
 
@@ -410,8 +459,16 @@ void UDPSrc::apply(bool force)
 
     if ((m_config.m_squelchGate != m_running.m_squelchGate) || force)
     {
-        m_squelchThreshold = m_config.m_outputSampleRate * m_config.m_squelchGate;
+        int gateNbSamples = m_config.m_inputSampleRate * m_config.m_squelchGate;
+        m_squelchThreshold = gateNbSamples;
         initSquelch(m_squelchOpen);
+        m_agc.setStepDownDelay(gateNbSamples); // same delay for up and down
+        m_agc.setGate(gateNbSamples);
+    }
+
+    if ((m_config.m_squelch != m_running.m_squelch) || force)
+    {
+        m_agc.setThreshold(m_config.m_squelch * (1<<30));
     }
 
     if ((m_config.m_udpAddressStr != m_running.m_udpAddressStr) || force)

plugins/channelrx/udpsrc/udpsrc.h

@@ -26,6 +26,7 @@
 #include "dsp/interpolator.h"
 #include "dsp/phasediscri.h"
 #include "dsp/movingaverage.h"
+#include "dsp/agc.h"
 #include "util/udpsink.h"
 #include "util/message.h"
 #include "audio/audiofifo.h"
@@ -47,6 +48,7 @@ public:
 		FormatLSBMono,
 		FormatUSBMono,
 		FormatAMMono,
+		FormatAMNoDCMono,
 		FormatNone
 	};
 
@@ -77,6 +79,7 @@ public:
 			Real squelchDB,
 			Real squelchGate,
 			bool squelchEnabled,
+			bool agc,
 			bool force);
 	void setSpectrum(MessageQueue* messageQueue, bool enabled);
 	double getMagSq() const { return m_magsq; }
@@ -168,6 +171,7 @@ protected:
 		Real getSquelchDB() const { return m_squelchDB; }
 		Real getSquelchGate() const { return m_squelchGate; }
 		bool getSquelchEnabled() const { return m_squelchEnabled; }
+		bool getAGC() const { return m_agc; }
 		bool getForce() const { return m_force; }
 
 		static MsgUDPSrcConfigureImmediate* create(
@@ -178,6 +182,7 @@ protected:
 				Real squelchDB,
 				Real squelchGate,
 				bool squelchEnabled,
+				bool agc,
 				bool force)
 		{
 			return new MsgUDPSrcConfigureImmediate(
@@ -188,6 +193,7 @@ protected:
 					squelchDB,
 					squelchGate,
 					squelchEnabled,
+					agc,
 					force);
 		}
 
@@ -199,6 +205,7 @@ protected:
 		Real m_squelchDB;
         Real m_squelchGate; // seconds
 		bool m_squelchEnabled;
+		bool m_agc;
 		bool m_force;
 
 		MsgUDPSrcConfigureImmediate(
@@ -209,6 +216,7 @@ protected:
                 Real squelchDB,
                 Real squelchGate,
                 bool squelchEnabled,
+                bool agc,
                 bool force) :
 			Message(),
 			m_gain(gain),
@@ -218,6 +226,7 @@ protected:
 			m_squelchDB(squelchDB),
             m_squelchGate(squelchGate),
 			m_squelchEnabled(squelchEnabled),
+			m_agc(agc),
 			m_force(force)
 		{ }
 	};
@@ -254,6 +263,7 @@ protected:
         Real m_squelch; //!< squared magnitude
         Real m_squelchGate; //!< seconds
         bool m_squelchEnabled;
+        bool m_agc;
         bool m_audioActive;
         bool m_audioStereo;
         int m_volume;
@@ -274,6 +284,7 @@ protected:
             m_squelch(1e-6),
             m_squelchGate(0.0),
             m_squelchEnabled(true),
+            m_agc(false),
             m_audioActive(false),
             m_audioStereo(false),
             m_volume(20),
@@ -294,6 +305,7 @@ protected:
     double m_inMagsq;
     MovingAverage<double> m_outMovingAverage;
     MovingAverage<double> m_inMovingAverage;
+    MovingAverage<double> m_amMovingAverage;
 
 	Real m_scale;
 	Complex m_last, m_this;
@@ -319,6 +331,7 @@ protected:
 
 	char *m_udpAudioBuf;
 	static const int m_udpAudioPayloadSize = 8192; //!< UDP audio samples buffer. No UDP block on Earth is larger than this
+	static const Real m_agcTarget = 16384.0f;
 
     PhaseDiscriminators m_phaseDiscri;
 
@@ -327,6 +340,8 @@ protected:
     int  m_squelchCloseCount;
     int m_squelchThreshold; //!< number of samples computed from given gate
 
+    MagAGC m_agc;
+
 	QMutex m_settingsMutex;
 
 	void apply(bool force);

plugins/channelrx/udpsrc/udpsrcgui.cpp

@@ -347,6 +347,7 @@ void UDPSrcGUI::applySettingsImmediate(bool force)
 			ui->squelch->value() * 1.0f,
 			ui->squelchGate->value() * 0.01f,
 			ui->squelch->value() != -100,
+			ui->agc->isChecked(),
 			force);
 	}
 }
@@ -448,6 +449,10 @@ void UDPSrcGUI::applySettings(bool force)
 				sampleFormat = UDPSrc::FormatAMMono;
 				ui->fmDeviation->setEnabled(false);
 				break;
+            case 8:
+                sampleFormat = UDPSrc::FormatAMNoDCMono;
+                ui->fmDeviation->setEnabled(false);
+                break;
 			default:
 				sampleFormat = UDPSrc::FormatS16LE;
 				ui->fmDeviation->setEnabled(false);
@@ -544,6 +549,11 @@ void UDPSrcGUI::on_audioStereo_toggled(bool stereo __attribute__((unused)))
 	applySettingsImmediate();
 }
 
+void UDPSrcGUI::on_agc_toggled(bool agc __attribute__((unused)))
+{
+    applySettingsImmediate();
+}
+
 void UDPSrcGUI::on_gain_valueChanged(int value)
 {
 	ui->gainText->setText(tr("%1").arg(value/10.0, 0, 'f', 1));

plugins/channelrx/udpsrc/udpsrcgui.h

@@ -76,6 +76,7 @@ private slots:
 	void on_volume_valueChanged(int value);
 	void on_squelch_valueChanged(int value);
 	void on_squelchGate_valueChanged(int value);
+	void on_agc_toggled(bool agc);
 	void tick();
 
 private:

plugins/channelrx/udpsrc/udpsrcgui.ui

@@ -333,6 +333,19 @@
         </property>
        </widget>
       </item>
+      <item>
+       <widget class="ButtonSwitch" name="agc">
+        <property name="toolTip">
+         <string>Toggle AGC (only for AM and SSB)</string>
+        </property>
+        <property name="text">
+         <string>AGC</string>
+        </property>
+        <property name="checkable">
+         <bool>true</bool>
+        </property>
+       </widget>
+      </item>
       <item>
        <widget class="QToolButton" name="audioActive">
         <property name="toolTip">
@@ -504,6 +517,11 @@
           <string>S16LE AM Mono</string>
          </property>
         </item>
+        <item>
+         <property name="text">
+          <string>S16LE AM !DC Mono</string>
+         </property>
+        </item>
        </widget>
       </item>
      </layout>
@@ -782,6 +800,11 @@
    <header>gui/valuedialz.h</header>
    <container>1</container>
   </customwidget>
+  <customwidget>
+   <class>ButtonSwitch</class>
+   <extends>QToolButton</extends>
+   <header>gui/buttonswitch.h</header>
+  </customwidget>
  </customwidgets>
  <resources>
   <include location="../../../sdrbase/resources/res.qrc"/>