diff --git a/sdrbase/dsp/dspdevicesinkengine.cpp b/sdrbase/dsp/dspdevicesinkengine.cpp
index 71733fb5e..a5afbf317 100644
--- a/sdrbase/dsp/dspdevicesinkengine.cpp
+++ b/sdrbase/dsp/dspdevicesinkengine.cpp
@@ -168,10 +168,10 @@ QString DSPDeviceSinkEngine::sinkDeviceDescription()
 	return cmd.getDeviceDescription();
 }
 
-void DSPDeviceSinkEngine::work()
+void DSPDeviceSinkEngine::work(int nbWriteSamples)
 {
 	SampleSourceFifo* sampleFifo = m_deviceSampleSink->getSampleFifo();
-	unsigned int nbWriteSamples = sampleFifo->getChunkSize();
+	//unsigned int nbWriteSamples = sampleFifo->getChunkSize();
 	SampleVector::iterator writeBegin;
 	sampleFifo->getWriteIterator(writeBegin);
 	SampleVector::iterator writeAt = writeBegin;
@@ -407,7 +407,7 @@ void DSPDeviceSinkEngine::handleSetSink(DeviceSampleSink* sink)
 	if(m_deviceSampleSink != 0)
 	{
 		qDebug("DSPDeviceSinkEngine::handleSetSink: set %s", qPrintable(sink->getDeviceDescription()));
-		connect(m_deviceSampleSink->getSampleFifo(), SIGNAL(dataWrite()), this, SLOT(handleData()), Qt::QueuedConnection);
+		connect(m_deviceSampleSink->getSampleFifo(), SIGNAL(dataWrite(int)), this, SLOT(handleData(int)), Qt::QueuedConnection);
 	}
 	else
 	{
@@ -415,11 +415,11 @@ void DSPDeviceSinkEngine::handleSetSink(DeviceSampleSink* sink)
 	}
 }
 
-void DSPDeviceSinkEngine::handleData()
+void DSPDeviceSinkEngine::handleData(int nbSamples)
 {
 	if(m_state == StRunning)
 	{
-		work();
+		work(nbSamples);
 	}
 }
 
diff --git a/sdrbase/dsp/dspdevicesinkengine.h b/sdrbase/dsp/dspdevicesinkengine.h
index 45155dc38..5d4b72945 100644
--- a/sdrbase/dsp/dspdevicesinkengine.h
+++ b/sdrbase/dsp/dspdevicesinkengine.h
@@ -105,7 +105,7 @@ private:
 	quint64 m_centerFrequency;
 
 	void run();
-	void work(); //!< transfer samples from beseband sources to sink if in running state
+	void work(int nbWriteSamples); //!< transfer samples from beseband sources to sink if in running state
 
 	State gotoIdle();     //!< Go to the idle state
 	State gotoInit();     //!< Go to the acquisition init state from idle
@@ -115,7 +115,7 @@ private:
 	void handleSetSink(DeviceSampleSink* sink); //!< Manage sink setting
 
 private slots:
-	void handleData(); //!< Handle data when samples from source FIFO are ready to be processed
+	void handleData(int nbSamples); //!< Handle data when samples have to be written to the sample FIFO
 	void handleInputMessages(); //!< Handle input message queue
 	void handleSynchronousMessages(); //!< Handle synchronous messages with the thread
 	void handleForwardToSpectrumSink(int nbSamples);
diff --git a/sdrbase/dsp/samplesourcefifo.cpp b/sdrbase/dsp/samplesourcefifo.cpp
index 569f48977..87d561b09 100644
--- a/sdrbase/dsp/samplesourcefifo.cpp
+++ b/sdrbase/dsp/samplesourcefifo.cpp
@@ -52,7 +52,7 @@ void SampleSourceFifo::init()
 
 void SampleSourceFifo::readAdvance(SampleVector::iterator& readUntil, unsigned int nbSamples)
 {
-    QMutexLocker mutexLocker(&m_mutex);
+//    QMutexLocker mutexLocker(&m_mutex);
     assert(nbSamples < m_samplesChunkSize/2);
 
     m_ir = (m_ir + nbSamples) % m_size;
@@ -63,21 +63,21 @@ void SampleSourceFifo::readAdvance(SampleVector::iterator& readUntil, unsigned i
 
     if (m_init)
     {
-        emit dataWrite();
+        emit dataWrite(m_size);
         m_init = false;
     }
     else if (i_delta > 0)
     {
-        if (i_delta <= m_samplesChunkSize)
+        if (i_delta <= m_size/2) // m_samplesChunkSize)
         {
-            emit dataWrite();
+            emit dataWrite(m_size/2);
         }
     }
     else
     {
-        if (i_delta + m_size <= m_samplesChunkSize)
+        if (i_delta + m_size <= m_size/2) //m_samplesChunkSize)
         {
-            emit dataWrite();
+            emit dataWrite(m_size/2);
         }
     }
 }
@@ -88,7 +88,7 @@ void SampleSourceFifo::write(const Sample& sample)
     m_data[m_iw+m_size] = sample;
 
     {
-        QMutexLocker mutexLocker(&m_mutex);
+//        QMutexLocker mutexLocker(&m_mutex);
         m_iw = (m_iw+1) % m_size;
     }
 }
@@ -108,7 +108,7 @@ void SampleSourceFifo::bumpIndex(SampleVector::iterator& writeAt)
     m_data[m_iw+m_size] = m_data[m_iw];
 
     {
-        QMutexLocker mutexLocker(&m_mutex);
+//        QMutexLocker mutexLocker(&m_mutex);
         m_iw = (m_iw+1) % m_size;
     }
 
diff --git a/sdrbase/dsp/samplesourcefifo.h b/sdrbase/dsp/samplesourcefifo.h
index 83ed4ee9f..601e56cc8 100644
--- a/sdrbase/dsp/samplesourcefifo.h
+++ b/sdrbase/dsp/samplesourcefifo.h
@@ -54,8 +54,8 @@ private:
     QMutex m_mutex;
 
 signals:
-    void dataWrite();             // signal data is read past a read chunk of samples and write is needed
-    void dataRead(int nbSamples); // signal a read has been done for a number of samples
+    void dataWrite(int nbSamples); // signal data is read past a threshold and writing new samples to fill in is needed
+    void dataRead(int nbSamples);  // signal a read has been done for a number of samples
 };
 
 #endif /* SDRBASE_DSP_SAMPLESOURCEFIFO_H_ */