Make a dedicated CW transition smoothing class

plugins/channeltx/modssb/ssbmod.cpp

@@ -52,12 +52,7 @@ SSBMod::SSBMod(BasebandSampleSink* sampleSink) :
 	m_afInput(SSBModInputNone),
 	m_levelCalcCount(0),
 	m_peakLevel(0.0f),
-	m_levelSum(0.0f),
-	m_fadeInCounter(0),
-	m_fadeOutCounter(0),
-	m_nbFadeSamples(96),
-	m_fadeInSamples(0),
-	m_fadeOutSamples(0)
+	m_levelSum(0.0f)
 {
 	setObjectName("SSBMod");
 
@@ -98,7 +93,7 @@ SSBMod::SSBMod(BasebandSampleSink* sampleSink) :
 	m_cwKeyer.setWPM(13);
 	m_cwKeyer.setMode(CWKeyer::CWNone);
 
-	makeFadeSamples();
+	m_cwSmoother.setNbFadeSamples(96); // 2 ms at 48 kHz
     apply();
 }
 
@@ -120,9 +115,6 @@ SSBMod::~SSBMod()
         delete m_DSBFilterBuffer;
     }
 
-    delete[] m_fadeInSamples;
-    delete[] m_fadeOutSamples;
-
     DSPEngine::instance()->removeAudioSource(&m_audioFifo);
 }
 
@@ -314,17 +306,7 @@ void SSBMod::pullAF(Complex& sample)
 
         if (m_cwKeyer.getSample())
         {
-        	m_fadeOutCounter = 0;
-
-        	if (m_fadeInCounter < m_nbFadeSamples)
-        	{
-        		fadeFactor = m_fadeInSamples[m_fadeInCounter];
-        		m_fadeInCounter++;
-        	}
-        	else
-        	{
-        		fadeFactor = 1.0f;
-        	}
+            m_cwSmoother.getFadeSample(true, fadeFactor);
 
         	if (m_running.m_dsb)
         	{
@@ -343,13 +325,8 @@ void SSBMod::pullAF(Complex& sample)
         }
         else
         {
-        	m_fadeInCounter = 0;
-
-        	if (m_fadeOutCounter < m_nbFadeSamples)
+        	if (m_cwSmoother.getFadeSample(false, fadeFactor))
         	{
-        		fadeFactor = m_fadeOutSamples[m_fadeOutCounter];
-        		m_fadeOutCounter++;
-
             	if (m_running.m_dsb)
             	{
             		Real t = m_toneNco.next() * fadeFactor;
@@ -502,29 +479,6 @@ void SSBMod::pullAF(Complex& sample)
     }
 }
 
-void SSBMod::makeFadeSamples()
-{
-	if (m_fadeInSamples) {
-		delete[] m_fadeInSamples;
-	}
-
-	if (m_fadeOutSamples) {
-		delete[] m_fadeOutSamples;
-	}
-
-	m_fadeInSamples = new Real[m_nbFadeSamples];
-	m_fadeOutSamples = new Real[m_nbFadeSamples];
-
-	for (int i = 0; i < m_nbFadeSamples; i++)
-	{
-		m_fadeInSamples[i] = sin((i/ (Real) m_nbFadeSamples) * M_PI_2);
-		m_fadeOutSamples[i] = cos((i/ (Real) m_nbFadeSamples) * M_PI_2);
-	}
-
-	m_fadeInCounter = 0;
-	m_fadeOutCounter = 0;
-}
-
 void SSBMod::calculateLevel(Complex& sample)
 {
     Real t = sample.real(); // TODO: possibly adjust depending on sample type
@@ -720,8 +674,7 @@ void SSBMod::apply()
 	{
         m_settingsMutex.lock();
 	    m_cwKeyer.setSampleRate(m_config.m_audioSampleRate);
-	    m_nbFadeSamples = m_config.m_audioSampleRate / 500;     // 2ms
-	    makeFadeSamples();
+	    m_cwSmoother.setNbFadeSamples(m_config.m_audioSampleRate / 500); // 2 ms
         m_settingsMutex.unlock();
 	}
 

plugins/channeltx/modssb/ssbmod.h

@@ -383,11 +383,7 @@ private:
     Real m_peakLevel;
     Real m_levelSum;
     CWKeyer m_cwKeyer;
-    int m_fadeInCounter;
-    int m_fadeOutCounter;
-    int m_nbFadeSamples;
-    Real *m_fadeInSamples;
-    Real *m_fadeOutSamples;
+    CWSmoother m_cwSmoother;
 
     static const int m_levelNbSamples;
 
@@ -395,7 +391,6 @@ private:
     void pullAF(Complex& sample);
     void calculateLevel(Complex& sample);
     void modulateSample();
-    void makeFadeSamples();
     void openFileStream();
     void seekFileStream(int seekPercentage);
 };

sdrbase/dsp/cwkeyer.cpp

@@ -451,3 +451,82 @@ bool CWKeyer::eom()
 {
     return !(m_textPointer < m_text.length());
 }
+
+CWSmoother::CWSmoother() :
+        m_fadeInCounter(0),
+        m_fadeOutCounter(0),
+        m_nbFadeSamples(0),
+        m_fadeInSamples(0),
+        m_fadeOutSamples(0)
+{
+    setNbFadeSamples(96); // default is 2ms at 48 kHz sample rate
+}
+
+CWSmoother::~CWSmoother()
+{
+    delete[] m_fadeInSamples;
+    delete[] m_fadeOutSamples;
+}
+
+void CWSmoother::setNbFadeSamples(unsigned int nbFadeSamples)
+{
+    if (nbFadeSamples != m_nbFadeSamples)
+    {
+        QMutexLocker mutexLocker(&m_mutex);
+
+        m_nbFadeSamples = nbFadeSamples;
+
+        if (m_fadeInSamples) delete[] m_fadeInSamples;
+        if (m_fadeOutSamples) delete[] m_fadeOutSamples;
+
+        m_fadeInSamples = new float[m_nbFadeSamples];
+        m_fadeOutSamples = new float[m_nbFadeSamples];
+
+        for (int i = 0; i < m_nbFadeSamples; i++)
+        {
+            m_fadeInSamples[i] = sin((i/ (float) m_nbFadeSamples) * M_PI_2);
+            m_fadeOutSamples[i] = cos((i/ (float) m_nbFadeSamples) * M_PI_2);
+        }
+
+        m_fadeInCounter = 0;
+        m_fadeOutCounter = 0;
+    }
+}
+
+bool CWSmoother::getFadeSample(bool on, float& sample)
+{
+    QMutexLocker mutexLocker(&m_mutex);
+
+    if (on)
+    {
+        m_fadeOutCounter = 0;
+
+        if (m_fadeInCounter < m_nbFadeSamples)
+        {
+            sample = m_fadeInSamples[m_fadeInCounter];
+            m_fadeInCounter++;
+            return true;
+        }
+        else
+        {
+            sample = 1.0f;
+            return false;
+        }
+    }
+    else
+    {
+        m_fadeInCounter = 0;
+
+        if (m_fadeOutCounter < m_nbFadeSamples)
+        {
+            sample = m_fadeOutSamples[m_fadeOutCounter];
+            m_fadeOutCounter++;
+            return true;
+        }
+        else
+        {
+            sample = 0.0f;
+            return false;
+        }
+    }
+}

sdrbase/dsp/cwkeyer.h

@@ -99,6 +99,25 @@ private:
     void nextStateText();
 };
 
+/**
+ * Ancillary class to smooth out CW transitions with a sine shape
+ */
+class CWSmoother
+{
+public:
+    CWSmoother();
+    ~CWSmoother();
 
+    void setNbFadeSamples(unsigned int nbFadeSamples);
+    bool getFadeSample(bool on, float& sample);
+
+private:
+    QMutex m_mutex;
+    int m_fadeInCounter;
+    int m_fadeOutCounter;
+    unsigned int m_nbFadeSamples;
+    float *m_fadeInSamples;
+    float *m_fadeOutSamples;
+};
 
 #endif /* SDRBASE_DSP_CWKEYER_H_ */