diff --git a/src/freqshift.hh b/src/freqshift.hh
index 7b035ae..c18fe4b 100644
--- a/src/freqshift.hh
+++ b/src/freqshift.hh
@@ -4,6 +4,7 @@
 #include "config.hh"
 #include "traits.hh"
 #include "node.hh"
+#include "operators.hh"
 
 namespace sdr {
 
@@ -95,7 +96,7 @@ protected:
 
 protected:
   /** The size of the LUT. */
-  static const size_t _lut_size = 127;
+  static const size_t _lut_size = 128;
 };
 
 
diff --git a/src/gui/spectrum.cc b/src/gui/spectrum.cc
index 7eec3ba..811b5c4 100644
--- a/src/gui/spectrum.cc
+++ b/src/gui/spectrum.cc
@@ -5,8 +5,25 @@ using namespace sdr;
 using namespace sdr::gui;
 
 
+/* ********************************************************************************************* *
+ * SpectrumProvider
+ * ********************************************************************************************* */
+SpectrumProvider::SpectrumProvider(QObject *parent)
+  : QObject(parent)
+{
+  // pass...
+}
+
+SpectrumProvider::~SpectrumProvider() {
+  // pass...
+}
+
+
+/* ********************************************************************************************* *
+ * Spectrum
+ * ********************************************************************************************* */
 Spectrum::Spectrum(double rrate, size_t fftsize, size_t max_avg, QObject *parent) :
-  QObject(parent), _rrate(rrate), _fft_size(fftsize), _fft_buffer(fftsize),
+  SpectrumProvider(parent), _rrate(rrate), _fft_size(fftsize), _fft_buffer(fftsize),
   _compute(fftsize), _spectrum(fftsize), _sample_count(0), _N_samples(0),
   _trafo_count(0), _Ntrafo(max_avg),
   _samples_left(0), _input_type(Config::Type_UNDEFINED), _sample_rate(0)
@@ -69,6 +86,20 @@ Spectrum::isInputReal() const {
   return false;
 }
 
+double
+Spectrum::sampleRate() const {
+  return _sample_rate;
+}
+
+size_t
+Spectrum::fftSize() const {
+  return _fft_size;
+}
+
+const Buffer<double> &
+Spectrum::spectrum() const {
+  return _spectrum;
+}
 
 void
 Spectrum::handleBuffer(const RawBuffer &buffer, bool allow_overwrite)
diff --git a/src/gui/spectrum.hh b/src/gui/spectrum.hh
index 2780d77..60ed7e6 100644
--- a/src/gui/spectrum.hh
+++ b/src/gui/spectrum.hh
@@ -9,9 +9,39 @@
 namespace sdr {
 namespace gui {
 
+
+class SpectrumProvider: public QObject
+{
+  Q_OBJECT
+
+public:
+  SpectrumProvider(QObject *parent=0);
+
+  virtual ~SpectrumProvider();
+
+  /** Returns true if the input is real. */
+  virtual bool isInputReal() const = 0;
+
+  /** Retunrs the sample rate. */
+  virtual double sampleRate() const = 0;
+
+  /** Returns the FFT size. */
+  virtual size_t fftSize() const = 0;
+
+  /** Returns the current spectrum. */
+  virtual const Buffer<double> &spectrum() const = 0;
+
+signals:
+  /** Gets emitted once the spectrum was updated. */
+  void spectrumUpdated();
+  /** Gets emitted once the spectrum was reconfigured. */
+  void spectrumConfigured();
+};
+
+
 /** Calculates the power spectrum of a singnal. The spectrum gets updated with a specified
  * rate (if possible). */
-class Spectrum : public QObject, public SinkBase
+class Spectrum : public SpectrumProvider, public SinkBase
 {
   Q_OBJECT
 
@@ -36,20 +66,13 @@ public:
   bool isInputReal() const;
 
   /** Retunrs the sample rate. */
-  inline double sampleRate() const { return _sample_rate; }
+  double sampleRate() const;
 
   /** Returns the FFT size. */
-  inline size_t fftSize() const { return _fft_size; }
+  size_t fftSize() const;
 
   /** Returns the current spectrum. */
-  inline const Buffer<double> &spectrum() const { return _spectrum; }
-
-
-signals:
-  /** Gets emitted once the spectrum was updated. */
-  void spectrumUpdated();
-  /** Gets emitted once the spectrum was reconfigured. */
-  void spectrumConfigured();
+  const Buffer<double> &spectrum() const;
 
 protected:
   /** Updates the FFT in the _compute buffer. */
diff --git a/src/gui/spectrumview.cc b/src/gui/spectrumview.cc
index 395a660..dc98ed0 100644
--- a/src/gui/spectrumview.cc
+++ b/src/gui/spectrumview.cc
@@ -8,7 +8,7 @@
 using namespace sdr;
 using namespace sdr::gui;
 
-SpectrumView::SpectrumView(Spectrum *spectrum, QWidget *parent)
+SpectrumView::SpectrumView(SpectrumProvider *spectrum, QWidget *parent)
   : QWidget(parent), _spectrum(spectrum), _numXTicks(11), _numYTicks(6),
     _maxF(std::numeric_limits<double>::infinity()), _mindB(-60)
 {
diff --git a/src/gui/spectrumview.hh b/src/gui/spectrumview.hh
index 12cb351..b61205d 100644
--- a/src/gui/spectrumview.hh
+++ b/src/gui/spectrumview.hh
@@ -18,7 +18,7 @@ Q_OBJECT
 
 public:
   /** @param rrate Specifies the (approx) refreshrate of the FFT plot. */
-  explicit SpectrumView(Spectrum *spectrum, QWidget *parent=0);
+  explicit SpectrumView(SpectrumProvider *spectrum, QWidget *parent=0);
 
   inline size_t numXTicks() const { return _numXTicks; }
   inline void setNumXTicks(size_t N) { _numXTicks=N; update(); }
@@ -51,7 +51,7 @@ protected:
 
 protected:
   /** Holds a weak reference to the spectrum recorder object. */
-  Spectrum *_spectrum;
+  SpectrumProvider *_spectrum;
   /// The font being used for axis labels
   QFont _axisFont;
   /// The plot area
diff --git a/src/gui/waterfallview.cc b/src/gui/waterfallview.cc
index c39ba35..6735ddf 100644
--- a/src/gui/waterfallview.cc
+++ b/src/gui/waterfallview.cc
@@ -73,7 +73,7 @@ LinearColorMap::map(const double &value) {
 /* ****************************************************************************************** *
  *  Implementation of WaterFallView
  * ****************************************************************************************** */
-WaterFallView::WaterFallView(Spectrum *spectrum, size_t height, QWidget *parent)
+WaterFallView::WaterFallView(SpectrumProvider *spectrum, size_t height, QWidget *parent)
   : QWidget(parent), _spectrum(spectrum), _N(_spectrum->fftSize()), _M(height), _waterfall(_N,_M)
 {
   setMinimumHeight(height);
diff --git a/src/gui/waterfallview.hh b/src/gui/waterfallview.hh
index b6af394..c53265b 100644
--- a/src/gui/waterfallview.hh
+++ b/src/gui/waterfallview.hh
@@ -75,7 +75,7 @@ public:
    * @param spectrum Specifies the spectrum sink.
    * @param height Specifies the number of PSDs to display.
    * @param parent The parent widget. */
-  explicit WaterFallView(Spectrum *spectrum, size_t height=100, QWidget *parent = 0);
+  explicit WaterFallView(SpectrumProvider *spectrum, size_t height=100, QWidget *parent = 0);
 
 signals:
   void click(double f);
@@ -93,7 +93,7 @@ protected slots:
 
 protected:
   /** The spectrum sink. */
-  Spectrum *_spectrum;
+  SpectrumProvider *_spectrum;
   /** The size of the spectrum. */
   size_t _N;
   /** "Height of the spectrum. */
diff --git a/src/subsample.hh b/src/subsample.hh
index 7941865..f5ac16d 100644
--- a/src/subsample.hh
+++ b/src/subsample.hh
@@ -247,11 +247,18 @@ public:
   }
 
   /** Performs the sub-sampling. */
-  virtual void process(const Buffer<iScalar> &buffer, bool allow_overwrite) {
+  virtual void process(const Buffer<iScalar> &buffer, bool allow_overwrite)
+  {
+    // Short cut
+    if (1 == _frac) {
+      this->send(buffer, allow_overwrite);
+      return;
+    }
+
     size_t i=0, o=0;
     while (i<buffer.size()) {
       // First, fill sampler...
-      while ( (_mu > 1) && (i<buffer.size()) ) {
+      while ( (_mu >= 1) && (i<buffer.size()) ) {
         _dl[_dl_idx] = _dl[_dl_idx+8] = buffer[i]; i++;
         _dl_idx = (_dl_idx + 1) % 8; _mu -= 1;
       }
diff --git a/src/wavfile.cc b/src/wavfile.cc
index c8fd260..ad87d29 100644
--- a/src/wavfile.cc
+++ b/src/wavfile.cc
@@ -203,9 +203,7 @@ WavSource::next()
   if ((0 == _frames_left)) {
     // Close file
     _file.close();
-    Logger::get().log(LogMessage(LOG_DEBUG, "WavSource: End of file -> stop queue."));
-    // and signal queue to stop
-    Queue::get().stop();
+    signalEOS();
     return;
   }