Initial commit of redesigned internal processing and audio management.

Note: Several of the decoders are currently non-functioning in this
commit.  If you want the latest functioning codebase, please checkout
the commit prior to this one.  All decoders will eventually be updated
with this new architecture.

Currently broken:
- Logging and recording
- Aux decoders (Fleetsync/MDC/LoJack/Tait)
- LTR/Passport decoders

Changes in this commit:
- Module architecture for decoders and components with central
provisioning by the DecoderFactory
- Transition from Complex sample stream processing to float buffer
processing for improved memory management
- Redesigned filter structures - to support buffers and streams
- Resolved several memory leak issues
- Universal sharing of the thread pool manager
- Added centralized audio management with call/user prioritization and
new gui with mute/volume controls
- Embedded audio metadata for eventual streaming support
- Redesigned ProcessingChain to support independent re-use
- Added new TrafficChannelManager to handle traffic channel allocations
- Traffic Channel pool size and Call timeout available in P25 and
MPT1327 configs
- Redesigned channel and decoder gui components

src/module/demodulate/fm/FMDemodulatorModule.java

@@ -0,0 +1,196 @@
+/*******************************************************************************
+ *     SDR Trunk 
+ *     Copyright (C) 2014,2015 Dennis Sheirer
+ * 
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ * 
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ * 
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program.  If not, see <http://www.gnu.org/licenses/>
+ ******************************************************************************/
+package module.demodulate.fm;
+
+import module.Module;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import sample.Broadcaster;
+import sample.Listener;
+import sample.complex.ComplexBuffer;
+import sample.complex.IComplexBufferListener;
+import sample.real.IRealBufferProvider;
+import sample.real.RealBuffer;
+import source.tuner.frequency.AutomaticFrequencyControl_RB;
+import source.tuner.frequency.FrequencyCorrectionControl;
+import source.tuner.frequency.IFrequencyCorrectionController;
+import dsp.filter.FilterFactory;
+import dsp.filter.Window.WindowType;
+import dsp.filter.dc.AveragingDCRemovalFilter_RB;
+import dsp.filter.dc.DCRemovalFilter_RB;
+import dsp.filter.fir.complex.ComplexFIRFilter_CB_CB;
+import dsp.fm.FMDemodulator_CB;
+
+public class FMDemodulatorModule extends Module implements IComplexBufferListener, 
+				IFrequencyCorrectionController,	IRealBufferProvider
+{
+	private final static Logger mLog = LoggerFactory.getLogger( FMDemodulatorModule.class );
+	
+	/* Determines responsiveness of DC filter to frequency changes */
+	private static final float DC_REMOVAL_RATIO = 0.000003f;
+
+	private static final int SAMPLE_RATE = 48000;
+	
+	private ComplexFIRFilter_CB_CB mIQFilter;
+	private FMDemodulator_CB mDemodulator;
+	private Broadcaster<RealBuffer> mUnfilteredBufferBroadcaster = new Broadcaster<RealBuffer>();
+	private DCRemovalFilter_RB mDCRemovalFilter;
+	private AutomaticFrequencyControl_RB mAutomaticFrequencyControl;
+	private boolean mRemoveDC = true;
+
+	private Listener<RealBuffer> mListener;
+	
+	/**
+	 * FM Demodulator with integrated DC removal and automatic frequency
+	 * correction control.
+	 * 
+	 * @param pass - pass frequency for IQ filtering prior to demodulation.  This
+	 * frequency should be half of the signal bandwidth since the filter will
+	 * be applied against each of the inphase and quadrature signals and the 
+	 * combined pass bandwidth will be twice this value.
+	 * 
+	 * @param stop - stop frequency for IQ filtering prior to demodulation.
+	 * 
+	 * @param maxFrequencyCorrection - defines the maximum frequency +/- that 
+	 * the correction controller can adjust from the center tuned frequency.
+	 * Set this value to 0 for no frequency correction control.
+	 */
+	public FMDemodulatorModule( int pass, int stop, int maxFrequencyCorrection )
+	{
+		this( pass, stop, maxFrequencyCorrection, true );
+	}
+
+	public FMDemodulatorModule( int pass, int stop, int maxFrequencyCorrection, boolean removeDC )
+	{
+		assert( stop > pass );
+
+		mRemoveDC = removeDC;
+		
+		mIQFilter = new ComplexFIRFilter_CB_CB( FilterFactory.getLowPass( 
+				SAMPLE_RATE, pass, stop, 60, WindowType.HAMMING, true ), 1.0f );
+		
+		mDemodulator = new FMDemodulator_CB( 1.0f );
+		mIQFilter.setListener( mDemodulator );
+
+		mUnfilteredBufferBroadcaster = new Broadcaster<RealBuffer>();			
+		mDemodulator.setListener( mUnfilteredBufferBroadcaster );
+
+		if( maxFrequencyCorrection > 0 )
+		{
+			/* Frequency correction requires unfiltered samples in order to detect
+			 * the DC component present in a mistuned FM demodulated sample stream */
+			mAutomaticFrequencyControl = new AutomaticFrequencyControl_RB( maxFrequencyCorrection );
+			mUnfilteredBufferBroadcaster.addListener( mAutomaticFrequencyControl );
+		}
+		
+		if( mRemoveDC )
+		{
+			mDCRemovalFilter = new AveragingDCRemovalFilter_RB( DC_REMOVAL_RATIO );
+			mUnfilteredBufferBroadcaster.addListener( mDCRemovalFilter );
+		}
+	}
+
+	@Override
+	public boolean hasFrequencyCorrectionControl()
+	{
+		return mAutomaticFrequencyControl != null;
+	}
+
+	@Override
+	public FrequencyCorrectionControl getFrequencyCorrectionControl()
+	{
+		return mAutomaticFrequencyControl;
+	}
+
+	@Override
+	public Listener<ComplexBuffer> getComplexBufferListener()
+	{
+		return mIQFilter;
+	}
+
+	@Override
+	public void dispose()
+	{
+		mIQFilter.dispose();
+		mIQFilter = null;
+		
+		mDemodulator.dispose();
+		mDemodulator = null;
+		
+		mDCRemovalFilter.dispose();
+		mDCRemovalFilter = null;
+		
+		if( mAutomaticFrequencyControl != null )
+		{
+			mAutomaticFrequencyControl.dispose();
+			mAutomaticFrequencyControl = null;
+		}
+		
+		if( mUnfilteredBufferBroadcaster != null )
+		{
+			mUnfilteredBufferBroadcaster.dispose();
+			mUnfilteredBufferBroadcaster = null;
+		}
+	}
+
+	@Override
+	public void init()
+	{
+		mDemodulator.reset();
+		
+		if( mDCRemovalFilter != null )
+		{
+			mDCRemovalFilter.reset();
+		}
+		
+		if( mAutomaticFrequencyControl != null )
+		{
+			mAutomaticFrequencyControl.reset();
+		}
+	}
+
+	@Override
+	public void setRealBufferListener( Listener<RealBuffer> listener )
+	{
+		mListener = listener;
+		
+		if( mRemoveDC )
+		{
+			mDCRemovalFilter.setListener( listener );
+		}
+		else
+		{
+			mUnfilteredBufferBroadcaster.addListener( listener );
+		}
+	}
+
+	@Override
+	public void removeRealBufferListener()
+	{
+		if( mRemoveDC )
+		{
+			mDCRemovalFilter.removeListener();
+		}
+		else
+		{
+			mUnfilteredBufferBroadcaster.removeListener( mListener );
+		}
+	}
+}