Automatic Frequency Control enhancement. Provides default AFC and ability to disable in the Decoder tab of each channel. Spectral display includes visual indicators of frequency center (grey) and current AFC offset (yellow).

src/controller/channel/Channel.java

@@ -56,6 +56,7 @@ import controller.system.System;
 import decode.config.AuxDecodeConfiguration;
 import decode.config.DecodeConfigFactory;
 import decode.config.DecodeConfiguration;
+import dsp.afc.AutomaticFrequencyControl;
 import eventlog.config.EventLogConfiguration;
 
 @XmlSeeAlso( { Configuration.class } )
@@ -134,6 +135,27 @@ public class Channel extends Configuration
 		return mChannelType;
 	}
 
+	/**
+	 * Indicates if the channel is using Automatic Frequency Control
+	 * @return
+	 */
+	public boolean hasAFC()
+	{
+		return getAFC() != null;
+	}
+	
+	public AutomaticFrequencyControl getAFC()
+	{
+		if( isProcessing() )
+		{
+			return getProcessingChain().getAFC();
+		}
+		else
+		{
+			return null;
+		}
+	}
+
 	/**
 	 * Sets the resource manager responsible for this channel and registers
 	 * the channel manager as a listener to this channel.  Fires channel add

src/controller/channel/ProcessingChain.java

@@ -34,13 +34,11 @@ import record.wave.ComplexWaveRecorder;
 import record.wave.FloatWaveRecorder;
 import sample.Broadcaster;
 import sample.Listener;
-import sample.Provider;
 import sample.complex.ComplexSample;
 import source.ComplexSource;
 import source.FloatArraySource;
 import source.FloatSource;
 import source.Source;
-import source.Source.SampleType;
 import source.SourceException;
 import source.config.SourceConfigMixer;
 import source.tuner.Tuner;
@@ -57,6 +55,8 @@ import controller.state.ChannelState;
 import controller.state.ChannelState.State;
 import decode.Decoder;
 import decode.DecoderFactory;
+import dsp.afc.AutomaticFrequencyControl;
+import dsp.afc.FrequencyErrorListener;
 import eventlog.EventLogType;
 import eventlog.EventLogger;
 
@@ -73,6 +73,7 @@ public class ProcessingChain implements Listener<Message>
 	protected List<Recorder> mRecorders = new ArrayList<Recorder>();
 	protected ArrayList<EventLogger> mEventLoggers = new ArrayList<EventLogger>();
 	protected AudioOutput mAudioOutput;
+	protected AutomaticFrequencyControl mAFC;
 	protected ChannelState mChannelState;
 	protected ResourceManager mResourceManager;
 	private ScheduledFuture<?> mProcessorTask;
@@ -101,6 +102,14 @@ public class ProcessingChain implements Listener<Message>
 							mChannel.getAliasListName() );
 		}
 	}
+
+	/**
+	 * Automatic Frequency Control, or null if disabled
+	 */
+	public AutomaticFrequencyControl getAFC()
+	{
+		return mAFC;
+	}
 	
 	public Listener<List<ComplexSample>> getComplexListener()
 	{
@@ -379,6 +388,28 @@ public class ProcessingChain implements Listener<Message>
 					
 					mAudioOutput = new AudioOutput( threadName );
 					addFloatListener( mAudioOutput );
+					
+					/* Automatic frequency control */
+					if( mAFC != null )
+					{
+						mAFC.dispose();
+						mAFC = null;
+					}
+					
+					if( mSource instanceof FrequencyErrorListener &&
+						mChannel.getDecodeConfiguration().isAFCEnabled() )
+					{
+						FrequencyErrorListener listener = 
+								(FrequencyErrorListener)mSource;
+						
+						mAFC = new AutomaticFrequencyControl( listener );
+
+						/* Register AFC to receive frequency change events */
+						listener.addListener( mAFC );
+
+						/* Add AFC as listener to the decoder */
+						mDecoder.addUnfilteredFloatListener( mAFC );
+					}
 				}
 			}
 

src/decode/DecodeEditor.java

@@ -17,6 +17,11 @@
  ******************************************************************************/
 package decode;
 
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+import javax.swing.JCheckBox;
+
 import controller.Editor;
 import decode.config.DecodeConfiguration;
 
@@ -25,10 +30,25 @@ public class DecodeEditor extends Editor
     private static final long serialVersionUID = 1L;
 
     protected DecodeConfiguration mConfig;
-	
+    
+    protected JCheckBox mAFC;
+
 	public DecodeEditor( DecodeConfiguration config )
 	{
 		mConfig = config;
+
+		mAFC = new JCheckBox( "Automatic Frequency Control" );
+		mAFC.setSelected( mConfig.isAFCEnabled() );
+		mAFC.addActionListener( new ActionListener()
+		{
+			@Override
+			public void actionPerformed( ActionEvent arg0 )
+			{
+				mConfig.setAFC( mAFC.isSelected() );				
+			}
+		} );
+
+		add( mAFC, "wrap" );
 	}
 
 	public DecodeConfiguration getConfig()

src/decode/Decoder.java

@@ -20,6 +20,7 @@ package decode;
 import java.util.ArrayList;
 import java.util.List;
 
+import dsp.afc.AutomaticFrequencyControl;
 import message.Message;
 import sample.Broadcaster;
 import sample.Listener;
@@ -130,6 +131,8 @@ public abstract class Decoder implements Listener<Message>
     {
 		mFloatBroadcaster.addListener( listener );
     }
+    
+    public abstract void addUnfilteredFloatListener( Listener<Float> listener );
 
     public void removeFloatListener( Listener<Float> listener )
     {

src/decode/config/DecodeConfiguration.java

@@ -17,6 +17,7 @@
  ******************************************************************************/
 package decode.config;
 
+import javax.xml.bind.annotation.XmlElement;
 import javax.xml.bind.annotation.XmlRootElement;
 import javax.xml.bind.annotation.XmlSeeAlso;
 
@@ -32,6 +33,7 @@ import decode.DecoderType;
 public abstract class DecodeConfiguration extends Configuration
 {
 	private DecoderType mDecoderType = DecoderType.NBFM;
+	private boolean mAFCEnabled = true;
 
 	public DecodeConfiguration()
 	{
@@ -47,4 +49,20 @@ public abstract class DecodeConfiguration extends Configuration
 	{
 		return mDecoderType;
 	}
+
+	@XmlElement( name = "afc" )
+	public boolean getAFC()
+	{
+		return mAFCEnabled;
+	}
+	
+	public boolean isAFCEnabled()
+	{
+		return mAFCEnabled;
+	}
+	
+	public void setAFC( boolean enabled )
+	{
+		mAFCEnabled = enabled;
+	}
 }

src/decode/fleetsync2/Fleetsync2Decoder.java

@@ -181,4 +181,10 @@ public class Fleetsync2Decoder extends Decoder implements Instrumentable
 		        break;
 		}
     }
+
+	@Override
+    public void addUnfilteredFloatListener( Listener<Float> listener )
+    {
+		//Not implemented
+    }
 }

src/decode/ltrnet/LTRNetDecoder.java

@@ -24,6 +24,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 import message.MessageDirection;
+import sample.Listener;
 import source.Source.SampleType;
 import alias.AliasList;
 import bits.MessageFramer;
@@ -148,4 +149,14 @@ public class LTRNetDecoder extends Decoder implements Instrumentable
     {
         mLTRFSKDecoder.removeTap( tap );
     }
+
+	@Override
+    public void addUnfilteredFloatListener( Listener<Float> listener )
+    {
+		if( mDemodulator != null )
+		{
+			mDemodulator.addListener( listener );
+		}
+	    // TODO Auto-generated method stub
+    }
 }

src/decode/ltrnet/LTRNetEditor.java

@@ -21,6 +21,7 @@ import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 
 import javax.swing.DefaultComboBoxModel;
+import javax.swing.JCheckBox;
 import javax.swing.JComboBox;
 
 import message.MessageDirection;

src/decode/ltrstandard/LTRStandardDecoder.java

@@ -18,6 +18,7 @@
 package decode.ltrstandard;
 
 import message.MessageDirection;
+import sample.Listener;
 import source.Source.SampleType;
 import alias.AliasList;
 import bits.MessageFramer;
@@ -115,4 +116,13 @@ public class LTRStandardDecoder extends Decoder
     {
 	    return DecoderType.LTR_STANDARD;
     }
+
+	@Override
+    public void addUnfilteredFloatListener( Listener<Float> listener )
+    {
+		if( mDemodulator != null )
+		{
+			mDemodulator.addListener( listener );
+		}
+    }
 }

src/decode/mdc1200/MDCDecoder.java

@@ -25,6 +25,7 @@ import instrument.tap.stream.FloatTap;
 import java.util.ArrayList;
 import java.util.List;
 
+import sample.Listener;
 import source.Source.SampleType;
 import alias.AliasList;
 import bits.MessageFramer;
@@ -199,4 +200,10 @@ public class MDCDecoder extends Decoder implements Instrumentable
 			default:
 		}
     }
+
+	@Override
+    public void addUnfilteredFloatListener( Listener<Float> listener )
+    {
+		//Not implemented
+    }
 }

src/decode/mpt1327/MPT1327ChannelState.java

@@ -43,6 +43,7 @@ public class MPT1327ChannelState extends ChannelState
 	private ChannelMap mChannelMap;
 	private MPT1327ActivitySummary mActivitySummary;
 	
+	
 	public MPT1327ChannelState( ProcessingChain processingChain, 
 								AliasList aliasList,
 								ChannelMap channelMap )
@@ -156,72 +157,72 @@ public class MPT1327ChannelState extends ChannelState
 						setState( State.CONTROL );
 						break;
 					case GTC:
-						int channelNumber = mpt.getChannel();
-						
-						if( !getProcessingChain().getChannel()
-									.hasTrafficChannel( channelNumber ) )
+						if( mpt.isValidCall() )
 						{
-							String aliasListName = mProcessingChain
-										.getChannel().getAliasListName();
+							int channelNumber = mpt.getChannel();
 							
-							Channel traffic = getTrafficChannel( channelNumber, 
-															aliasListName );
-							
-							/* Set the system and site to same as control channel */
-							traffic.setSystem( getProcessingChain().getChannel()
-									.getSystem(), false );
-							traffic.setSite( getProcessingChain().getChannel()
-									.getSite(), false );
+							if( !getProcessingChain().getChannel()
+										.hasTrafficChannel( channelNumber ) )
+							{
+								String aliasListName = mProcessingChain
+											.getChannel().getAliasListName();
+								
+								Channel traffic = getTrafficChannel( channelNumber, 
+																aliasListName );
+								
+								/* Set the system and site to same as control channel */
+								traffic.setSystem( getProcessingChain().getChannel()
+										.getSystem(), false );
+								traffic.setSite( getProcessingChain().getChannel()
+										.getSite(), false );
 
-							/* Add the traffic channel to the parent control channel */
-							getProcessingChain().getChannel()
-										.addTrafficChannel( channelNumber, traffic );
+								/* Add the traffic channel to the parent control channel */
+								getProcessingChain().getChannel()
+											.addTrafficChannel( channelNumber, traffic );
 
-							/* Start the traffic channel */
-							traffic.setEnabled( true );
-							
-							/* Set traffic channel state info */
-							MPT1327ChannelState trafficState = 
-									(MPT1327ChannelState)traffic
-										.getProcessingChain().getChannelState();
-							
-							MPT1327ChannelState controlState = 
-									(MPT1327ChannelState)getProcessingChain()
-												.getChannelState();
-							
-							trafficState.setChannelMap( controlState.getChannelMap() );
-							trafficState.setChannelNumber( channelNumber );
-							trafficState.setFromTalkgroup( mpt.getFromID() );
-							trafficState.setToTalkgroup( mpt.getToID() );
+								/* Start the traffic channel */
+								traffic.setEnabled( true );
+								
+								/* Set traffic channel state info */
+								MPT1327ChannelState trafficState = 
+										(MPT1327ChannelState)traffic
+											.getProcessingChain().getChannelState();
+								
+								MPT1327ChannelState controlState = 
+										(MPT1327ChannelState)getProcessingChain()
+													.getChannelState();
+								
+								trafficState.setChannelMap( controlState.getChannelMap() );
+								trafficState.setChannelNumber( channelNumber );
+								trafficState.setFromTalkgroup( mpt.getFromID() );
+								trafficState.setToTalkgroup( mpt.getToID() );
 
-							/* Add this control channel as message listener on the
-							 * traffic channel so we can receive call tear-down
-							 * messages */
-							traffic.addListener( (Listener<Message>)this );
-							
-							CallEventType type = traffic.isProcessing() ? 
-										CallEventType.CALL_START : 
-										CallEventType.CALL_START_NO_TUNER;
-							
-							/*
-							 * Set the traffic channel's call event model to
-							 * share the control channel's call event model
-							 */
-							traffic.getProcessingChain().getChannelState()
-									.setCallEventModel( mCallEventModel );
-							
-							mCallEventModel.add( 
-								new MPT1327CallEvent.Builder( type )
-									.aliasList( traffic.getProcessingChain().getAliasList() )
-									.channel( channelNumber )
-									.frequency( mChannelMap.getFrequency( channelNumber ) )
-									.from( mpt.getFromID() )
-									.to( mpt.getToID() )
-									.build() );
+								/* Add this control channel as message listener on the
+								 * traffic channel so we can receive call tear-down
+								 * messages */
+								traffic.addListener( (Listener<Message>)this );
+								
+								CallEventType type = traffic.isProcessing() ? 
+											CallEventType.CALL_START : 
+											CallEventType.CALL_START_NO_TUNER;
+								
+								/*
+								 * Set the traffic channel's call event model to
+								 * share the control channel's call event model
+								 */
+								traffic.getProcessingChain().getChannelState()
+										.setCallEventModel( mCallEventModel );
+								
+								mCallEventModel.add( 
+									new MPT1327CallEvent.Builder( type )
+										.aliasList( traffic.getProcessingChain().getAliasList() )
+										.channel( channelNumber )
+										.frequency( mChannelMap.getFrequency( channelNumber ) )
+										.from( mpt.getFromID() )
+										.to( mpt.getToID() )
+										.build() );
+							}
 						}
-						
-						long frequency = mChannelMap.getFrequency( channelNumber );
-						
 						break;
 					case CLEAR:
 					case MAINT:
@@ -237,7 +238,7 @@ public class MPT1327ChannelState extends ChannelState
 						mCallEventModel.add( 
 								new MPT1327CallEvent.Builder( CallEventType.SDM )
 									.aliasList( mAliasList )
-									.details( mpt.getMessageType().getDescription() )
+									.details( mpt.getMessage() )
 									.from( mpt.getFromID() )
 									.to( mpt.getToID() )
 									.build() );
@@ -378,6 +379,7 @@ public class MPT1327ChannelState extends ChannelState
 		traffic.setSourceConfiguration( source );
 
 		DecodeConfigMPT1327 decode = new DecodeConfigMPT1327();
+		
 		traffic.setDecodeConfiguration( decode );
 		
 		traffic.setAliasListName( aliasListName );

src/decode/mpt1327/MPT1327Decoder.java

@@ -25,13 +25,16 @@ import instrument.tap.stream.FloatTap;
 import java.util.ArrayList;
 import java.util.List;
 
+import log.Log;
 import sample.Broadcaster;
+import sample.Listener;
 import source.Source.SampleType;
 import alias.AliasList;
 import bits.MessageFramer;
 import bits.SyncPattern;
 import decode.Decoder;
 import decode.DecoderType;
+import dsp.afc.AutomaticFrequencyControl;
 import dsp.filter.DCRemovalFilter;
 import dsp.filter.FilterFactory;
 import dsp.filter.Filters;
@@ -95,7 +98,7 @@ public class MPT1327Decoder extends Decoder implements Instrumentable
 			/* I/Q low pass filtering narrow band FM demodulator */
 			mNBFMDemodulator = new NBFMDemodulator( 
 				FilterFactory.getLowPass( 48000, 4000, 73, WindowType.HAMMING ), 
-			    1.0002 );
+			    1.0002, true );
 			
 			this.addComplexListener( mNBFMDemodulator );
 			
@@ -166,6 +169,15 @@ public class MPT1327Decoder extends Decoder implements Instrumentable
         mControlMessageFramer.addMessageListener( mMessageProcessor );
         mTrafficMessageFramer.addMessageListener( mMessageProcessor );
 	}
+    
+	@Override
+    public void addUnfilteredFloatListener( Listener<Float> listener )
+    {
+		if( mNBFMDemodulator != null )
+		{
+			mNBFMDemodulator.addListener( listener );
+		}
+    }
 
 	@Override
     public DecoderType getType()

src/decode/mpt1327/MPT1327Message.java

@@ -281,6 +281,13 @@ public class MPT1327Message extends Message
         return mCRC[ 0 ] == CRC.PASSED || 
         	   mCRC[ 0 ] == CRC.CORRECTED;
     }
+    
+    public boolean isValidCall()
+    {
+    	return getPrefix() != 0 &&
+    		   getIdent1() != 0 &&
+    		   getIdent2() != 0;
+    }
 
     /**
      * Constructs a decoded message string
@@ -312,9 +319,9 @@ public class MPT1327Message extends Message
      */
     public MPTMessageType getMessageType()
     {
-    	int type = mMessage.getInt( B1_MESSAGE_TYPE );
+    	int value = mMessage.getInt( B1_MESSAGE_TYPE );
 
-    	return MPTMessageType.fromNumber( type );
+    	return MPTMessageType.fromNumber( value );
     }
 
     /**
@@ -766,6 +773,7 @@ public class MPT1327Message extends Message
     		case HEAD_PLUS2:
     		case HEAD_PLUS3:
     		case HEAD_PLUS4:
+    			sb.append( " " );
     			sb.append( getSDM() );
     			break;
     	}
@@ -947,9 +955,12 @@ public class MPT1327Message extends Message
     			break;
     		case USER:
 			default:
-            	sb.append( format( prefix, 3 ) );
-            	sb.append( "-" );
-            	sb.append( format( ident, 4) );
+				if( prefix != 0 || ident != 0 )
+				{
+	            	sb.append( format( prefix, 3 ) );
+	            	sb.append( "-" );
+	            	sb.append( format( ident, 4) );
+				}
             	break;
     	}
 
@@ -1701,7 +1712,7 @@ public class MPT1327Message extends Message
 	public enum Descriptor
 	{
 		DESC0( "EXTENDED ADDRESSING INFORMATION", 
-			   "SERIAL NUMBER", 
+			   "ESN", 
 			   "SINGLE SEGMENT TRANSACTIONS (SST) ONLY" ),
 		DESC1( "PSTN DIALED DIGITS", "RESERVED", "N/A" ),
 		DESC2( "PABX EXTENSION", "RESERVED", "N/A" ),

src/decode/nbfm/NBFMConventionalDecoder.java

@@ -17,9 +17,11 @@
  ******************************************************************************/
 package decode.nbfm;
 
+import sample.Listener;
 import source.Source.SampleType;
 import decode.Decoder;
 import decode.DecoderType;
+import dsp.afc.AutomaticFrequencyControl;
 import dsp.filter.DCRemovalFilter2;
 import dsp.nbfm.FilteringNBFMDemodulator;
 
@@ -32,7 +34,7 @@ public class NBFMConventionalDecoder extends Decoder
 	private static final double sDC_REMOVAL_RATIO = 0.000003;
 
 	private FilteringNBFMDemodulator mDemodulator;
-	private DCRemovalFilter2 mDCRemovalFilter; 
+	private DCRemovalFilter2 mDCRemovalFilter;
 	
 	public NBFMConventionalDecoder( SampleType sampleType )
 	{
@@ -60,7 +62,7 @@ public class NBFMConventionalDecoder extends Decoder
 			 */
 			mDCRemovalFilter = new DCRemovalFilter2( sDC_REMOVAL_RATIO );
 			mDemodulator.addListener( mDCRemovalFilter );
-
+			
 			/**
 			 * Route the demodulated, filtered samples back to this class to send
 			 * to all registered listeners
@@ -74,4 +76,13 @@ public class NBFMConventionalDecoder extends Decoder
     {
 	    return DecoderType.NBFM;
     }
+
+	@Override
+    public void addUnfilteredFloatListener( Listener<Float> listener )
+    {
+		if( mDemodulator != null )
+		{
+			mDemodulator.addListener( listener );
+		}
+    }
 }

src/decode/nbfm/NBFMEditor.java

@@ -17,12 +17,16 @@
  ******************************************************************************/
 package decode.nbfm;
 
+import javax.swing.JCheckBox;
+
 import decode.DecodeEditor;
 import decode.config.DecodeConfiguration;
 
 public class NBFMEditor extends DecodeEditor
 {
     private static final long serialVersionUID = 1L;
+    
+    private JCheckBox mAFC;
 
 	public NBFMEditor( DecodeConfiguration config )
 	{

src/decode/p25/P25Decoder.java

@@ -24,10 +24,12 @@ import instrument.tap.stream.FloatTap;
 import java.util.ArrayList;
 import java.util.List;
 
+import sample.Listener;
 import source.Source.SampleType;
 import alias.AliasList;
 import decode.Decoder;
 import decode.DecoderType;
+import dsp.afc.AutomaticFrequencyControl;
 import dsp.filter.DCRemovalFilter2;
 import dsp.fsk.C4FMDecoder;
 import dsp.nbfm.FilteringNBFMDemodulator;
@@ -141,4 +143,11 @@ public class P25Decoder extends Decoder implements Instrumentable
 				break;
 		}
     }
+
+	@Override
+    public void addUnfilteredFloatListener( Listener<Float> listener )
+    {
+	    // TODO Auto-generated method stub
+	    
+    }
 }

src/decode/passport/PassportDecoder.java

@@ -23,12 +23,14 @@ import instrument.tap.Tap;
 import java.util.ArrayList;
 import java.util.List;
 
+import sample.Listener;
 import source.Source.SampleType;
 import alias.AliasList;
 import bits.MessageFramer;
 import bits.SyncPattern;
 import decode.Decoder;
 import decode.DecoderType;
+import dsp.afc.AutomaticFrequencyControl;
 import dsp.filter.DCRemovalFilter2;
 import dsp.fsk.LTRFSKDecoder;
 import dsp.nbfm.FilteringNBFMDemodulator;
@@ -138,4 +140,13 @@ public class PassportDecoder extends Decoder implements Instrumentable
     {
 		mPassportFSKDecoder.removeTap( tap );
     }
+
+	@Override
+    public void addUnfilteredFloatListener( Listener<Float> listener )
+    {
+		if( mNBFMDemodulator != null )
+		{
+			mNBFMDemodulator.addListener( listener );
+		}
+    }
 }

src/dsp/afc/AutomaticFrequencyControl.java

@@ -0,0 +1,169 @@
+package dsp.afc;
+
+import sample.Listener;
+import source.tuner.FrequencyChangeListener;
+import buffer.FloatAveragingBuffer;
+
+public class AutomaticFrequencyControl implements Listener<Float>, 
+												  FrequencyChangeListener
+{
+	private static float LARGE_ERROR = 10000.0f;
+	private static float MEDIUM_ERROR = 5000.0f;
+	private static float SMALL_ERROR = 1000.0f;
+	private static float FINE_ERROR = 500.0f;
+	private static int SAMPLE_THRESHOLD = 15000;
+	private Mode mMode = Mode.FAST;
+	
+	private FloatAveragingBuffer mBuffer = 
+			new FloatAveragingBuffer( SAMPLE_THRESHOLD );
+
+	private int mSampleCounter = 0;
+	private int mSkipCounter = 0;
+	private int mSkipThreshold = 4;
+	private int mErrorCorrection = 0;
+	private long mCurrentFrequency;
+	private int mCurrentSampleRate;
+	private FrequencyErrorListener mListener;
+	
+	public enum Mode
+	{
+		NORMAL,FAST;
+	}
+	
+	public AutomaticFrequencyControl( FrequencyErrorListener listener )
+	{
+		mListener = listener;
+	}
+	
+	public void dispose()
+	{
+		mListener = null;
+		mBuffer = null;
+	}
+	
+	public int getErrorCorrection()
+	{
+		return mErrorCorrection;
+	}
+	
+	public void reset()
+	{
+		mErrorCorrection = 0;
+		mMode = Mode.FAST;
+		dispatch();
+	}
+	
+	private void dispatch()
+	{
+		if( mListener != null )
+		{
+			mListener.setError( mErrorCorrection );
+		}
+	}
+
+	@Override
+    public void receive( Float sample )
+    {
+		if( mMode == Mode.FAST )
+		{
+			float average = mBuffer.get( sample.floatValue() );
+			
+			mSampleCounter++;
+			
+			if( mSampleCounter >= SAMPLE_THRESHOLD )
+			{
+				mSampleCounter = 0;
+				
+				update( average );
+			}
+		}
+		else
+		{
+			mSkipCounter++;
+			
+			if( mSkipCounter >= mSkipThreshold )
+			{
+				mSkipCounter = 0;
+
+				float average = mBuffer.get( sample.floatValue() );
+				
+				mSampleCounter++;
+				
+				if( mSampleCounter >= SAMPLE_THRESHOLD )
+				{
+					mSampleCounter = 0;
+					
+					update( average );
+				}
+			}
+		}
+    }
+	
+	private void update( float average )
+	{
+		int correction = 0;
+		
+		if( average > LARGE_ERROR )
+		{
+			correction = -1000;
+			mMode = Mode.FAST;
+		}
+		else if( average > MEDIUM_ERROR )
+		{
+			correction = -500;
+			mMode = Mode.FAST;
+		}
+		else if( average > SMALL_ERROR )
+		{
+			correction = -100;
+			mMode = Mode.NORMAL;
+		}
+		else if( average > FINE_ERROR )
+		{
+			correction = -50;
+			mMode = Mode.NORMAL;
+		}
+		else if( average < -LARGE_ERROR )
+		{
+			correction = 1000;
+			mMode = Mode.FAST;
+		}
+		else if( average < -MEDIUM_ERROR )
+		{
+			correction = 500;
+			mMode = Mode.FAST;
+		}
+		else if( average < -SMALL_ERROR )
+		{
+			correction = 100;
+			mMode = Mode.NORMAL;
+		}
+		else if( average < -FINE_ERROR )
+		{
+			correction = 50;
+			mMode = Mode.NORMAL;
+		}
+
+		if( correction != 0 )
+		{
+			mErrorCorrection -= correction;
+			dispatch();
+		}
+		else
+		{
+			mMode = Mode.NORMAL;
+		}
+	}
+
+	@Override
+    public void frequencyChanged( long frequency, int bandwidth )
+    {
+		if( mCurrentFrequency != frequency || mCurrentSampleRate != bandwidth )
+		{
+			mCurrentFrequency = frequency;
+			mCurrentSampleRate = bandwidth;
+			
+			reset();
+		}
+    }
+}

src/dsp/afc/FrequencyErrorListener.java

@@ -0,0 +1,10 @@
+package dsp.afc;
+
+import source.tuner.FrequencyChangeListener;
+
+public interface FrequencyErrorListener
+{
+	public void setError( int error );
+	
+	public void addListener( FrequencyChangeListener listener );
+}

src/dsp/nbfm/NBFMDemodulator.java

@@ -17,9 +17,11 @@
  ******************************************************************************/
 package dsp.nbfm;
 
+import log.Log;
 import sample.Broadcaster;
 import sample.Listener;
 import sample.complex.ComplexSample;
+import dsp.afc.AutomaticFrequencyControl;
 import dsp.filter.ComplexFIRFilter;
 import dsp.filter.FilterFactory;
 import dsp.filter.Window.WindowType;
@@ -30,7 +32,17 @@ public class NBFMDemodulator implements Listener<ComplexSample>
 	private ComplexFIRFilter mIQFilter;
 	private FMDiscriminator mDiscriminator;
 
-	public NBFMDemodulator( double[] iqFilter, double iqGain )
+	/**
+	 * Implements a quadrature narrow-band demodulator that produces float
+	 * valued demodulated, audio filtered output samples.
+	 */
+	public NBFMDemodulator()
+	{
+		this( FilterFactory.getLowPass( 48000, 4000, 73, WindowType.HAMMING ), 
+			  1.0002, true );
+	}
+
+	public NBFMDemodulator( double[] iqFilter, double iqGain, boolean afc )
 	{
 		mIQFilter = new ComplexFIRFilter( iqFilter, iqGain );
 
@@ -54,16 +66,6 @@ public class NBFMDemodulator implements Listener<ComplexSample>
 		mIQFilter.dispose();
 	}
 	
-	/**
-	 * Implements a quadrature narrow-band demodulator that produces float
-	 * valued demodulated, audio filtered output samples.
-	 */
-	public NBFMDemodulator()
-	{
-		this( FilterFactory.getLowPass( 48000, 4000, 73, WindowType.HAMMING ), 
-			  1.0002 );
-	}
-
 	/**
 	 * Receive method for complex samples that are fed into this class to be
 	 * processed

src/source/tuner/TunerChannelSource.java

@@ -24,22 +24,23 @@ import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
+import log.Log;
 import sample.Listener;
-import sample.Provider;
 import sample.complex.ComplexSample;
 import sample.complex.ComplexSampleAssembler;
 import source.ComplexSource;
-import source.Source.SampleType;
 import source.SourceException;
 import util.Oscillator;
 import controller.ThreadPoolManager;
 import controller.ThreadPoolManager.ThreadType;
+import dsp.afc.FrequencyErrorListener;
 import dsp.filter.ComplexFilter;
 import dsp.filter.FilterFactory;
 import dsp.filter.Window.WindowType;
 
 public class TunerChannelSource extends ComplexSource
 							 implements FrequencyChangeListener,
+							 			FrequencyErrorListener,
 							 			Listener<Float[]>
 {
 	private static int sCHANNEL_RATE = 48000;
@@ -55,8 +56,10 @@ public class TunerChannelSource extends ComplexSource
 
 	private ComplexSampleAssembler mBufferAssembler = 
 								new ComplexSampleAssembler( 3000 );
-	private long mTunerFrequency;
+	private long mTunerFrequency = 0;
+	private int mTunerFrequencyError = 0;
 	private int mTunerSampleRate;
+	private FrequencyChangeListener mFrequencyChangeListener;
 	private ThreadPoolManager mThreadPoolManager;
 	private ScheduledFuture<?> mTaskHandle;
 	
@@ -95,6 +98,8 @@ public class TunerChannelSource extends ComplexSource
     @Override
     public void dispose()
     {
+    	mFrequencyChangeListener = null;
+    	
 		//Tell the tuner to release our resources
 		mTuner.removeListener( (FrequencyChangeListener)this );
 		mTuner.releaseChannel( this );
@@ -155,43 +160,33 @@ public class TunerChannelSource extends ComplexSource
 	@Override
     public void frequencyChanged( long frequency, int bandwidth )
     {
-		
-		/* Frequency change */
-		if( frequency != mTunerFrequency )
+		/* Send change to Automatic Frequency Control */
+		if( mFrequencyChangeListener != null )
 		{
-			long frequencyOffset = frequency - mTunerChannel.getFrequency();
-			
-			if( mSineWaveGenerator == null )
-			{
-				mSineWaveGenerator = 
-					new Oscillator( frequencyOffset, bandwidth );
-			}
-			else
-			{
-				mSineWaveGenerator.setFrequency( frequencyOffset );
-			}
-			
-			/* Clear the buffer for the frequency to take immediate effect */
-			mBuffer.clear();
-			
-			mTunerFrequency = frequency;
+			mFrequencyChangeListener.frequencyChanged( frequency, bandwidth );
 		}
+		
+		long frequencyOffset = frequency - 
+				   mTunerChannel.getFrequency() -
+				   mTunerFrequencyError;
+
+		if( mSineWaveGenerator == null )
+		{
+			mSineWaveGenerator = new Oscillator( frequencyOffset, bandwidth );
+		}
+		else
+		{
+			mSineWaveGenerator.setFrequency( frequencyOffset );
+		}
+		
+		/* Clear the buffer for the frequency to take immediate effect */
+//		mBuffer.clear();
+		
+		mTunerFrequency = frequency;
 
 		/* Bandwidth/Sample rate change */
 		if( bandwidth != mTunerSampleRate )
 		{
-			long frequencyOffset = frequency - mTunerChannel.getFrequency();
-			
-			if( mSineWaveGenerator == null )
-			{
-				mSineWaveGenerator = 
-					new Oscillator( frequencyOffset, bandwidth );
-			}
-			else
-			{
-				mSineWaveGenerator.setSampleRate( bandwidth );
-			}
-
 			/* Get the original decimation filter output listener */
 			Listener<ComplexSample> listener = null;
 			
@@ -270,4 +265,26 @@ public class TunerChannelSource extends ComplexSource
 			}
         }
 	}
+
+	/**
+	 * Automatic Frequency Control
+	 */
+	@Override
+    public void setError( int error )
+    {
+		if( mTunerFrequencyError != error )
+		{
+			mTunerFrequencyError = error;
+			frequencyChanged( mTunerFrequency, mTunerSampleRate );
+		}
+		
+		Log.info( "TunerChannelSource - mistuned quantity:" + 
+						mTunerFrequencyError + " Hz" );
+    }
+
+	@Override
+    public void addListener( FrequencyChangeListener listener )
+    {
+		mFrequencyChangeListener = listener;
+    }
 }

src/source/tuner/rtl/RTL2832TunerController.java

@@ -1354,7 +1354,7 @@ public abstract class RTL2832TunerController extends TunerController
 		RATE_1_440MHZ( 0x0500, 0x0000, 1440000, "1.440 MHz" ),
 		RATE_1_680MHZ( 0x044A, 0x0000, 1680000, "1.680 MHz" ),
 		RATE_1_824MHZ( 0x03F3, 0x0000, 1824000, "1.824 MHz" ),
-		RATE_2_016MHZ( 0x0387, 0x0000, 2016000, "2.016 MHz" );
+		RATE_2_016MHZ( 0x038F, 0x0000, 2016000, "2.016 MHz" );
 
 		/* Note: usb4java library buffer processing scheme doesn't seem capable 
 		 * of supporting these rates */

src/spectrum/OverlayPanel.java

@@ -302,6 +302,32 @@ public class OverlayPanel extends JPanel
 					 xaxis, (float)(getSize().getHeight()) - mSpectrumInset ) );
     }
 
+    /**
+     * Draws a vertical line at the xaxis
+     */
+    private void drawAFC( Graphics2D graphics, float xaxis, boolean isError )
+    {
+    	float height = (float)(getSize().getHeight()) - mSpectrumInset;
+
+    	if( isError )
+    	{
+        	graphics.setColor( Color.YELLOW );
+
+        	graphics.draw( new Line2D.Float( xaxis, height * 0.75f, 
+					 xaxis, height - 1.0f ) );
+    	}
+    	else
+    	{
+        	graphics.setColor( Color.LIGHT_GRAY );
+
+        	graphics.draw( new Line2D.Float( xaxis, height * 0.65f, 
+					 xaxis, height - 1.0f ) );
+    	}
+    	
+    	
+    }
+
+    
     /**
      * Returns the x-axis value corresponding to the frequency
      */
@@ -436,8 +462,22 @@ public class OverlayPanel extends JPanel
                 		   yAxis,
                 		   width );
             }
+            
+            /* Draw Automatic Frequency Control line */
+            if( channel.hasAFC() )
+            {
+            	int frequency = (int)tunerChannel.getFrequency();
+            	
+            	int error = frequency + channel.getAFC().getErrorCorrection();
+            	
+                drawAFC( graphics, getAxisFromFrequency( frequency ), false );
+
+                drawAFC( graphics, getAxisFromFrequency( error ), true );
+            }
     	}
     }
+    
+    
     /**
      * Draws a textual label at the x/y position, clipping the end of the text
      * to fit within the maxwidth value.