diff --git a/include-gpl/dsp/channelizer.h b/include-gpl/dsp/channelizer.h
index d988bd0b8..a45b21fed 100644
--- a/include-gpl/dsp/channelizer.h
+++ b/include-gpl/dsp/channelizer.h
@@ -2,6 +2,7 @@
 #define INCLUDE_CHANNELIZER_H
 
 #include <list>
+#include <QMutex>
 #include "dsp/samplesink.h"
 #include "util/export.h"
 #include "util/message.h"
@@ -70,6 +71,7 @@ protected:
 	int m_currentOutputSampleRate;
 	int m_currentCenterFrequency;
 	SampleVector m_sampleBuffer;
+	QMutex m_mutex;
 
 	void applyConfiguration();
 	bool signalContainsChannel(Real sigStart, Real sigEnd, Real chanStart, Real chanEnd) const;
@@ -81,53 +83,3 @@ signals:
 };
 
 #endif // INCLUDE_CHANNELIZER_H
-
-#if 0
-
-#ifndef INCLUDE_CHANNELIZER_H
-#define INCLUDE_CHANNELIZER_H
-
-#include "samplesink.h"
-#include "spectrum.h"
-#include "nco.h"
-#include "interpolator.h"
-#include "pidcontroller.h"
-#include "hardware/audiofifo.h"
-
-class AudioOutput;
-
-class Channelizer : public SampleSink {
-public:
-	Channelizer();
-	~Channelizer();
-
-#if 0
-	void setGLSpectrum(GLSpectrum* glSpectrum);
-#endif
-
-	size_t workUnitSize();
-	size_t work(SampleVector::const_iterator begin, SampleVector::const_iterator end);
-
-private:
-#if 0
-	NCO m_nco;
-	Interpolator m_interpolator;
-	Real m_distance;
-	Interpolator m_interpolator2;
-	Real m_distance2;
-
-	SampleVector m_buffer;
-	size_t m_bufferFill;
-	Complex m_lastSample;
-
-	AudioOutput* m_audioOutput;
-	AudioFifo m_audioFifo;
-	Real m_resampler;
-	PIDController m_resamplerCtrl;
-
-	Spectrum m_spectrum;
-#endif
-};
-
-#endif // INCLUDE_CHANNELIZER_H
-#endif
diff --git a/sdrbase/dsp/channelizer.cpp b/sdrbase/dsp/channelizer.cpp
index 23988779c..1481cd3fc 100644
--- a/sdrbase/dsp/channelizer.cpp
+++ b/sdrbase/dsp/channelizer.cpp
@@ -37,18 +37,29 @@ void Channelizer::feed(const SampleVector::const_iterator& begin, const SampleVe
 		return;
 	}
 
-	for(SampleVector::const_iterator sample = begin; sample != end; ++sample) {
+	m_mutex.lock();
+
+	for(SampleVector::const_iterator sample = begin; sample != end; ++sample)
+	{
 		Sample s(*sample);
 		FilterStages::iterator stage = m_filterStages.begin();
-		while(stage != m_filterStages.end()) {
+
+		for (; stage != m_filterStages.end(); ++stage)
+		{
 			if(!(*stage)->work(&s))
+			{
 				break;
-			++stage;
+			}
 		}
+
 		if(stage == m_filterStages.end())
+		{
 			m_sampleBuffer.push_back(s);
+		}
 	}
 
+	m_mutex.unlock();
+
 	m_sampleSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), positiveOnly);
 	m_sampleBuffer.clear();
 }
@@ -125,12 +136,16 @@ void Channelizer::applyConfiguration()
 		return;
 	}
 
+	m_mutex.lock();
+
 	freeFilterChain();
 
 	m_currentCenterFrequency = createFilterChain(
 		m_inputSampleRate / -2, m_inputSampleRate / 2,
 		m_requestedCenterFrequency - m_requestedOutputSampleRate / 2, m_requestedCenterFrequency + m_requestedOutputSampleRate / 2);
 
+	m_mutex.unlock();
+
 	m_currentOutputSampleRate = m_inputSampleRate / (1 << m_filterStages.size());
 
 	qDebug() << "Channelizer::applyConfiguration in=" << m_inputSampleRate