Updates version to 0.4.0 alpha 5

429 polyphase channelizer 25khz channel rate

build.gradle

@@ -15,7 +15,7 @@ repositories {
     mavenCentral()
 }
 
-version = '0.4.0-alpha.3'
+version = '0.4.0-alpha.5'
 sourceCompatibility = 1.8
 
 sourceSets {

src/main/java/io/github/dsheirer/channel/metadata/Attribute.java

@@ -20,6 +20,7 @@ package io.github.dsheirer.channel.metadata;
 
 public enum Attribute
 {
+    BUFFER_OVERFLOW,
     CHANNEL_CONFIGURATION_NAME,
     CHANNEL_CONFIGURATION_SITE,
     CHANNEL_CONFIGURATION_SYSTEM,

src/main/java/io/github/dsheirer/channel/metadata/AttributeChangeRequest.java

@@ -116,6 +116,16 @@ public class AttributeChangeRequest<T>
         return null;
     }
 
+    public Boolean getBooleanValue()
+    {
+        if(mValue instanceof Boolean)
+        {
+            return (Boolean)mValue;
+        }
+
+        return false;
+    }
+
     /**
      * Returns the value as a DecoderType or null if the value is not a DecoderType instance.
      */

src/main/java/io/github/dsheirer/channel/metadata/ChannelMetadataModel.java

@@ -1,19 +1,16 @@
 /*******************************************************************************
- * sdrtrunk
- * Copyright (C) 2014-2017 Dennis Sheirer
+ * sdr-trunk
+ * Copyright (C) 2014-2018 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 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.
+ * 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/>
+ * 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 io.github.dsheirer.channel.metadata;
@@ -21,9 +18,11 @@ package io.github.dsheirer.channel.metadata;
 import io.github.dsheirer.channel.state.State;
 import io.github.dsheirer.controller.channel.Channel;
 import io.github.dsheirer.sample.Listener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import javax.swing.table.AbstractTableModel;
-import java.awt.*;
+import java.awt.EventQueue;
 import java.text.DecimalFormat;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -32,6 +31,8 @@ import java.util.Map;
 
 public class ChannelMetadataModel extends AbstractTableModel implements Listener<MutableMetadataChangeEvent>
 {
+    private final static Logger mLog = LoggerFactory.getLogger(ChannelMetadataModel.class);
+
     private final DecimalFormat FREQUENCY_FORMATTER = new DecimalFormat( "#.00000" );
 
     public static final int COLUMN_STATE = 0;
@@ -45,7 +46,7 @@ public class ChannelMetadataModel extends AbstractTableModel implements Listener
     public static final int COLUMN_CONFIGURATION_NAME = 8;
     public static final int COLUMN_MESSAGE = 9;
 
-    private static final String[] COLUMNS = {"State", "Decoder", "Channel", "Frequency", "Primary From", "Primary To",
+    private static final String[] COLUMNS = {"Status", "Decoder", "Channel", "Frequency", "Primary From", "Primary To",
          "Secondary From", "Secondary To", "Channel Name", "Message"};
 
     private List<MutableMetadata> mChannelMetadata = new ArrayList();
@@ -184,7 +185,11 @@ public class ChannelMetadataModel extends AbstractTableModel implements Listener
 
                     return null;
                 case COLUMN_MESSAGE:
-                    if(metadata.hasMessageType() | metadata.hasMessage())
+                    if(metadata.isBufferOverflow())
+                    {
+                        return "**OVERFLOW**";
+                    }
+                    else if(metadata.hasMessageType() || metadata.hasMessage())
                     {
                         StringBuilder sb = new StringBuilder();
                         if(metadata.hasMessageType())
@@ -248,6 +253,7 @@ public class ChannelMetadataModel extends AbstractTableModel implements Listener
                         case CHANNEL_STATE:
                             fireTableCellUpdated(rowIndex, COLUMN_STATE);
                             break;
+                        case BUFFER_OVERFLOW:
                         case MESSAGE:
                         case MESSAGE_TYPE:
                             fireTableCellUpdated(rowIndex, COLUMN_MESSAGE);

src/main/java/io/github/dsheirer/channel/metadata/ChannelMetadataPanel.java

@@ -120,8 +120,6 @@ public class ChannelMetadataPanel extends JPanel implements ListSelectionListene
         mForegroundColors.put(State.FADE, Color.DARK_GRAY);
         mBackgroundColors.put(State.IDLE, Color.WHITE);
         mForegroundColors.put(State.IDLE, Color.DARK_GRAY);
-        mBackgroundColors.put(State.OVERFLOW, Color.RED);
-        mForegroundColors.put(State.OVERFLOW, Color.YELLOW);
         mBackgroundColors.put(State.RESET, Color.PINK);
         mForegroundColors.put(State.RESET, Color.YELLOW);
         mBackgroundColors.put(State.TEARDOWN, Color.DARK_GRAY);

src/main/java/io/github/dsheirer/channel/metadata/Metadata.java

@@ -41,6 +41,7 @@ public class Metadata
     protected boolean mUpdated;
     protected DecoderType mPrimaryDecoderType;
     protected boolean mSelected;
+    protected boolean mBufferOverflow;
     protected State mState = State.IDLE;
     protected String mChannelConfigurationSystem;
     protected String mChannelConfigurationSite;
@@ -173,6 +174,14 @@ public class Metadata
         return mSelected;
     }
 
+    /**
+     * Indicates if the channel for this metadata is in a buffer overflow state.
+     */
+    public boolean isBufferOverflow()
+    {
+        return mBufferOverflow;
+    }
+
     /**
      * List of de-duplicated broadcast channels aggregated from the primary and secondary TO/FROM aliases.
      */

src/main/java/io/github/dsheirer/channel/metadata/MutableMetadata.java

@@ -80,6 +80,10 @@ public class MutableMetadata extends Metadata implements Listener<AttributeChang
     {
         switch(request.getAttribute())
         {
+            case BUFFER_OVERFLOW:
+                mBufferOverflow = request.getBooleanValue();
+                broadcast(Attribute.BUFFER_OVERFLOW);
+                break;
             case CHANNEL_CONFIGURATION_SYSTEM:
                 mChannelConfigurationSystem = request.getStringValue();
                 broadcast(Attribute.CHANNEL_CONFIGURATION_SYSTEM);
@@ -164,6 +168,7 @@ public class MutableMetadata extends Metadata implements Listener<AttributeChang
     public void resetTemporalAttributes()
     {
         mDoNotRecord = null;
+        mBufferOverflow = false;
 
         if(hasMessage())
         {

src/main/java/io/github/dsheirer/channel/state/ChannelState.java

@@ -135,21 +135,8 @@ public class ChannelState extends Module implements ICallEventProvider, IDecoder
     @Override
     public void stop()
     {
-        mMutableMetadata.resetAllAttributes();
-
-        mTrafficChannelEndListener = null;
-
-        if(mTrafficChannelCallEvent != null)
-        {
-            mTrafficChannelCallEvent.end();
-            broadcast(mTrafficChannelCallEvent);
-        }
-
-        mTrafficChannelCallEvent = null;
-
+        processTeardownState();
         mSquelchLocked = false;
-
-        setState(State.TEARDOWN);
     }
 
     public void dispose()
@@ -346,8 +333,7 @@ public class ChannelState extends Module implements ICallEventProvider, IDecoder
                     break;
             }
 
-            mMutableMetadata.receive(new AttributeChangeRequest<State>(Attribute.CHANNEL_STATE,
-                mSourceOverflow ? State.OVERFLOW : mState));
+            mMutableMetadata.receive(new AttributeChangeRequest<State>(Attribute.CHANNEL_STATE, mState));
         }
     }
 
@@ -370,8 +356,19 @@ public class ChannelState extends Module implements ICallEventProvider, IDecoder
     {
         mSourceOverflow = overflow;
 
-        mMutableMetadata.receive(new AttributeChangeRequest<State>(Attribute.CHANNEL_STATE,
-            mSourceOverflow ? State.OVERFLOW : mState));
+        mMutableMetadata.receive(new AttributeChangeRequest<Boolean>(Attribute.BUFFER_OVERFLOW, mSourceOverflow));
+    }
+
+    /**
+     * Indicates if this channel's sample buffer is in overflow state, meaning that the inbound sample
+     * stream is not being processed fast enough and samples are being thrown away until the processing can
+     * catch up.
+     *
+     * @return true if the channel is in overflow state.
+     */
+    public boolean isOverflow()
+    {
+        return mSourceOverflow;
     }
 
     /**
@@ -410,9 +407,13 @@ public class ChannelState extends Module implements ICallEventProvider, IDecoder
 
         mMutableMetadata.receive(new AttributeChangeRequest<State>(Attribute.CHANNEL_STATE, mState));
 
-        if(mTrafficChannelEndListener != null)
+        if(mTrafficChannelEndListener != null && mTrafficChannelCallEvent != null)
         {
+            mTrafficChannelCallEvent.end();
+            broadcast(mTrafficChannelCallEvent);
             mTrafficChannelEndListener.callEnd(mTrafficChannelCallEvent.getChannel());
+            mTrafficChannelEndListener = null;
+            mTrafficChannelCallEvent = null;
         }
     }
 

src/main/java/io/github/dsheirer/channel/state/State.java

@@ -34,7 +34,7 @@ public enum State
             @Override
             public boolean canChangeTo(State state)
             {
-                return state == CALL |
+                return state == CALL ||
                        state == CONTROL ||
                        state == DATA ||
                        state == ENCRYPTED ||
@@ -108,8 +108,7 @@ public enum State
             public boolean canChangeTo(State state)
             {
                 return state != FADE &&
-                       state != RESET &&
-                       state != OVERFLOW;
+                       state != RESET;
             }
         },
     /**
@@ -121,25 +120,10 @@ public enum State
             public boolean canChangeTo(State state)
             {
                 return state != TEARDOWN &&
-                       state != RESET &&
-                       state != OVERFLOW;
-            }
-        },
-    /**
-     * Indicates that the channel's sample buffer has overflowed and new buffer samples are no longer being
-     * delivered to the channel.  This state persists until the processing catches up and reduces the number
-     * of samples in the input buffer below a threshold value.  Transition to and from this state is exclusively
-     * managed by the Channel State and no other channel states can be processed from the channel decoders
-     * until the channel state is taken out of overflow.
-     */
-    OVERFLOW("OVERFLOW")
-        {
-            @Override
-            public boolean canChangeTo(State state)
-            {
-                return false;
+                       state != RESET;
             }
         },
+
     /**
      * Indicates that the channel has been reset and is ready to use for a new decoding session.
      */
@@ -191,4 +175,10 @@ public enum State
     {
         return mDisplayValue;
     }
+
+    @Override
+    public String toString()
+    {
+        return mDisplayValue;
+    }
 }

src/main/java/io/github/dsheirer/channel/traffic/TrafficChannelManager.java

@@ -186,7 +186,7 @@ public class TrafficChannelManager extends Module implements ICallEventProvider,
             if(frequency > 0)
             {
                 Channel channel = getChannel(callEvent.getChannel(), new TunerChannel(frequency,
-                    mDecodeConfiguration.getDecoderType().getChannelBandwidth()));
+                    mDecodeConfiguration.getChannelSpecification().getBandwidth()));
 
                 if(channel != null)
                 {

src/main/java/io/github/dsheirer/controller/channel/Channel.java

@@ -489,14 +489,14 @@ public class Channel extends Configuration implements Listener<SourceEvent>
                 SourceConfigTuner config = (SourceConfigTuner)mSourceConfiguration;
 
                 mTunerChannel = new TunerChannel(config.getFrequency(),
-                    mDecodeConfiguration.getDecoderType().getChannelBandwidth());
+                    mDecodeConfiguration.getChannelSpecification().getBandwidth());
             }
             else if(mSourceConfiguration.getSourceType() == SourceType.RECORDING)
             {
                 SourceConfigRecording config = (SourceConfigRecording)mSourceConfiguration;
 
                 mTunerChannel = new TunerChannel(config.getFrequency(),
-                    mDecodeConfiguration.getDecoderType().getChannelBandwidth());
+                    mDecodeConfiguration.getChannelSpecification().getBandwidth());
             }
         }
 

src/main/java/io/github/dsheirer/controller/channel/ChannelProcessingManager.java

@@ -212,7 +212,7 @@ public class ChannelProcessingManager implements ChannelEventListener
         try
         {
             source = mSourceManager.getSource(channel.getSourceConfiguration(),
-                channel.getDecodeConfiguration().getDecoderType().getChannelBandwidth());
+                channel.getDecodeConfiguration().getChannelSpecification());
         }
         catch(SourceException se)
         {

src/main/java/io/github/dsheirer/dsp/filter/channelizer/ComplexPolyphaseChannelizerM2.java

@@ -63,7 +63,7 @@ public class ComplexPolyphaseChannelizerM2 extends AbstractComplexPolyphaseChann
 {
     private final static Logger mLog = LoggerFactory.getLogger(ComplexPolyphaseChannelizerM2.class);
 
-    private static final int DEFAULT_MINIMUM_CHANNEL_BANDWIDTH = 12500;
+    private static final int DEFAULT_MINIMUM_CHANNEL_BANDWIDTH = 25000;
 
     //Sized at 152 buffers a second where max = 5 seconds and reset = 2 seconds worth of buffers
     private IFFTProcessor mIFFTProcessor = new IFFTProcessor((5 * 152), (2 * 152));

src/main/java/io/github/dsheirer/dsp/filter/channelizer/PolyphaseChannelManager.java

@@ -29,6 +29,7 @@ import io.github.dsheirer.source.Source;
 import io.github.dsheirer.source.SourceEvent;
 import io.github.dsheirer.source.SourceException;
 import io.github.dsheirer.source.tuner.TunerController;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 import io.github.dsheirer.source.tuner.channel.TunerChannel;
 import io.github.dsheirer.source.tuner.channel.TunerChannelSource;
 import org.slf4j.Logger;
@@ -62,7 +63,7 @@ import java.util.concurrent.CopyOnWriteArrayList;
 public class PolyphaseChannelManager implements ISourceEventProcessor
 {
     private final static Logger mLog = LoggerFactory.getLogger(PolyphaseChannelManager.class);
-    private static final double MINIMUM_CHANNEL_BANDWIDTH = 12500.0;
+    private static final double MINIMUM_CHANNEL_BANDWIDTH = 25000.0;
     private static final double CHANNEL_OVERSAMPLING = 2.0;
     private static final int POLYPHASE_CHANNELIZER_TAPS_PER_CHANNEL = 9;
     private static final int POLYPHASE_SYNTHESIZER_TAPS_PER_CHANNEL = 9;
@@ -141,7 +142,7 @@ public class PolyphaseChannelManager implements ISourceEventProcessor
      * @param tunerChannel specifying center frequency and bandwidth.
      * @return source or null.
      */
-    public TunerChannelSource getChannel(TunerChannel tunerChannel)
+    public TunerChannelSource getChannel(TunerChannel tunerChannel, ChannelSpecification channelSpecification)
     {
         PolyphaseChannelSource channelSource = null;
 
@@ -155,10 +156,17 @@ public class PolyphaseChannelManager implements ISourceEventProcessor
             {
                 long centerFrequency = mChannelCalculator.getCenterFrequencyForIndexes(polyphaseIndexes);
 
-                channelSource = new PolyphaseChannelSource(tunerChannel, outputProcessor, mChannelSourceEventListener,
-                    mChannelCalculator.getChannelSampleRate(), centerFrequency);
+                try
+                {
+                    channelSource = new PolyphaseChannelSource(tunerChannel, outputProcessor, mChannelSourceEventListener,
+                        mChannelCalculator.getChannelSampleRate(), centerFrequency, channelSpecification);
 
-                mChannelSources.add(channelSource);
+                    mChannelSources.add(channelSource);
+                }
+                catch(FilterDesignException fde)
+                {
+                    mLog.debug("Couldn't design final output low pass filter for polyphase channel source");
+                }
             }
         }
         catch(IllegalArgumentException iae)

src/main/java/io/github/dsheirer/dsp/filter/channelizer/PolyphaseChannelSource.java

@@ -16,22 +16,35 @@
 package io.github.dsheirer.dsp.filter.channelizer;
 
 import io.github.dsheirer.dsp.filter.channelizer.output.IPolyphaseChannelOutputProcessor;
+import io.github.dsheirer.dsp.filter.design.FilterDesignException;
+import io.github.dsheirer.dsp.filter.fir.FIRFilterSpecification;
+import io.github.dsheirer.dsp.filter.fir.complex.ComplexFIRFilter2;
+import io.github.dsheirer.dsp.filter.fir.remez.RemezFIRFilterDesigner;
 import io.github.dsheirer.sample.Listener;
 import io.github.dsheirer.sample.buffer.ReusableChannelResultsBuffer;
 import io.github.dsheirer.sample.buffer.ReusableComplexBuffer;
 import io.github.dsheirer.sample.buffer.ReusableComplexBufferAssembler;
 import io.github.dsheirer.source.SourceEvent;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 import io.github.dsheirer.source.tuner.channel.TunerChannel;
 import io.github.dsheirer.source.tuner.channel.TunerChannelSource;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.HashMap;
+import java.util.Map;
+
 public class PolyphaseChannelSource extends TunerChannelSource
 {
     private final static Logger mLog = LoggerFactory.getLogger(PolyphaseChannelSource.class);
 
     private ReusableComplexBufferAssembler mReusableComplexBufferAssembler;
     private IPolyphaseChannelOutputProcessor mPolyphaseChannelOutputProcessor;
+    private IPolyphaseChannelOutputProcessor mReplacementPolyphaseChannelOutputProcessor;
+    private long mReplacementFrequency;
+    private ComplexFIRFilter2 mLowPassFilter;
+    private static Map<Integer,float[]> sLowPassFilters = new HashMap();
+
     private double mChannelSampleRate;
     private long mIndexCenterFrequency;
     private long mChannelFrequencyCorrection;
@@ -46,15 +59,22 @@ public class PolyphaseChannelSource extends TunerChannelSource
      * @param producerSourceEventListener to receive source event requests (e.g. start/stop sample stream)
      * @param channelSampleRate for the downstream sample output
      * @param centerFrequency of the incoming polyphase channel(s)
+     * @throws FilterDesignException if a channel low pass filter can't be designed to the channel specification
      */
     public PolyphaseChannelSource(TunerChannel tunerChannel, IPolyphaseChannelOutputProcessor outputProcessor,
                                   Listener<SourceEvent> producerSourceEventListener, double channelSampleRate,
-                                  long centerFrequency)
+                                  long centerFrequency, ChannelSpecification channelSpecification)
+        throws FilterDesignException
     {
         super(producerSourceEventListener, tunerChannel);
         mPolyphaseChannelOutputProcessor = outputProcessor;
         mChannelSampleRate = channelSampleRate;
         mReusableComplexBufferAssembler = new ReusableComplexBufferAssembler(2500, mChannelSampleRate);
+
+        float[] filterCoefficients = getLowPassFilter(channelSampleRate, channelSpecification.getPassFrequency(),
+            channelSpecification.getStopFrequency());
+        mLowPassFilter = new ComplexFIRFilter2(filterCoefficients, 1.0f);
+
         setFrequency(centerFrequency);
     }
 
@@ -93,14 +113,33 @@ public class PolyphaseChannelSource extends TunerChannelSource
      */
     public void setPolyphaseChannelOutputProcessor(IPolyphaseChannelOutputProcessor outputProcessor, long frequency)
     {
-        //Lock on the channel output processor to block the channel results processor thread from servicing the
-        //channel output processor's buffer while we change out the processors.
-        synchronized(mPolyphaseChannelOutputProcessor)
+        //If this is the first time, simply assign the output processor
+        if(mPolyphaseChannelOutputProcessor == null)
+        {
+            mPolyphaseChannelOutputProcessor = outputProcessor;
+        }
+        //Otherwise, we have to swap out the processor on the sample processing thread
+        else
+        {
+            mReplacementPolyphaseChannelOutputProcessor = outputProcessor;
+            mReplacementFrequency = frequency;
+        }
+    }
+
+    /**
+     * Updates the output processor to use the new output processor provided by the external
+     * polyphase channel manager.  This method should only be executed on the sample processing
+     * thread, within the processChannelResults() method.
+     */
+    private void swapOutputProcessor()
+    {
+        if(mReplacementPolyphaseChannelOutputProcessor != null)
         {
             IPolyphaseChannelOutputProcessor existingProcessor = mPolyphaseChannelOutputProcessor;
 
             //Swap out the processor so that incoming samples can accumulate in the new channel output processor
-            mPolyphaseChannelOutputProcessor = outputProcessor;
+            mPolyphaseChannelOutputProcessor = mReplacementPolyphaseChannelOutputProcessor;
+            mReplacementPolyphaseChannelOutputProcessor = null;
 
             //Remove the buffer overflow listener and clear any previous buffer overflow state
             existingProcessor.setSourceOverflowListener(null);
@@ -109,18 +148,9 @@ public class PolyphaseChannelSource extends TunerChannelSource
             //Register to receive buffer overflow notifications so we can push them up through the source chain
             mPolyphaseChannelOutputProcessor.setSourceOverflowListener(this);
 
-            //Fully process the residual channel results buffer of the previous channel output processor
-            if(existingProcessor != null)
-            {
-                existingProcessor.processChannelResults(mReusableComplexBufferAssembler);
-            }
-
-            //Finally, setup the frequency offset for the output processor and reset the frequency correction value
-            //to allow consumers to adjust and calculate a new frequency correction value, if needed.
-            mIndexCenterFrequency = frequency;
-            mChannelFrequencyCorrection = 0;
+            //Finally, setup the frequency offset for the output processor.
+            mIndexCenterFrequency = mReplacementFrequency;
             mPolyphaseChannelOutputProcessor.setFrequencyOffset(getFrequencyOffset());
-            broadcastConsumerSourceEvent(SourceEvent.frequencyCorrectionChange(mChannelFrequencyCorrection));
         }
     }
 
@@ -133,12 +163,13 @@ public class PolyphaseChannelSource extends TunerChannelSource
      */
     public void receiveChannelResults(ReusableChannelResultsBuffer channelResultsBuffer)
     {
-        mReusableComplexBufferAssembler.updateTimestamp(channelResultsBuffer.getTimestamp());
-
-        if(mPolyphaseChannelOutputProcessor != null)
+        if(mReplacementPolyphaseChannelOutputProcessor != null)
         {
-            mPolyphaseChannelOutputProcessor.receiveChannelResults(channelResultsBuffer);
+            swapOutputProcessor();
         }
+
+        mReusableComplexBufferAssembler.updateTimestamp(channelResultsBuffer.getTimestamp());
+        mPolyphaseChannelOutputProcessor.receiveChannelResults(channelResultsBuffer);
     }
 
     /**
@@ -173,7 +204,6 @@ public class PolyphaseChannelSource extends TunerChannelSource
         if(mPolyphaseChannelOutputProcessor != null)
         {
             mPolyphaseChannelOutputProcessor.dispose();
-            mPolyphaseChannelOutputProcessor = null;
         }
     }
 
@@ -213,11 +243,7 @@ public class PolyphaseChannelSource extends TunerChannelSource
     @Override
     protected void processSamples()
     {
-        //Lock on the output processor so that it can't be changed in the middle of processing
-        synchronized(mPolyphaseChannelOutputProcessor)
-        {
-            mPolyphaseChannelOutputProcessor.processChannelResults(mReusableComplexBufferAssembler);
-        }
+        mPolyphaseChannelOutputProcessor.processChannelResults(mReusableComplexBufferAssembler);
     }
 
     /**
@@ -236,10 +262,7 @@ public class PolyphaseChannelSource extends TunerChannelSource
      */
     private void updateFrequencyOffset()
     {
-        synchronized(mPolyphaseChannelOutputProcessor)
-        {
-            mPolyphaseChannelOutputProcessor.setFrequencyOffset(getFrequencyOffset());
-        }
+        mPolyphaseChannelOutputProcessor.setFrequencyOffset(getFrequencyOffset());
     }
 
     @Override
@@ -248,4 +271,42 @@ public class PolyphaseChannelSource extends TunerChannelSource
         return "POLYPHASE [" + mPolyphaseChannelOutputProcessor.getInputChannelCount() + "] " +
             getTunerChannel().getFrequency();
     }
+
+    /**
+     * Creates a low-pass filter to use as the final cleanup filter for the decimated output stream
+     *
+     * @param sampleRate for the final output channel rate
+     * @param passFrequency for half of the desired channel rate
+     * @param stopFrequency for the attenuated band
+     * @return a newly designed filter or a previously designed (cached) filter
+     * @throws FilterDesignException
+     */
+    private float[] getLowPassFilter(double sampleRate, double passFrequency, double stopFrequency) throws FilterDesignException
+    {
+        //Use existing filter if we've already designed one
+        if(sLowPassFilters.containsKey((int)sampleRate))
+        {
+            return sLowPassFilters.get((int)sampleRate);
+        }
+
+        FIRFilterSpecification specification = FIRFilterSpecification.lowPassBuilder()
+            .sampleRate(sampleRate)
+            .gridDensity(16)
+            .passBandCutoff(passFrequency)
+            .passBandAmplitude(1.0)
+            .passBandRipple(0.01)
+            .stopBandStart(stopFrequency)
+            .stopBandAmplitude(0.0)
+            .stopBandRipple(0.01)
+            .build();
+
+        RemezFIRFilterDesigner designer = new RemezFIRFilterDesigner(specification);
+
+        //This will throw an exception if the filter cannot be designed
+        float[] taps = designer.getImpulseResponse();
+
+        sLowPassFilters.put((int)sampleRate, taps);
+
+        return taps;
+    }
 }

src/main/java/io/github/dsheirer/dsp/filter/channelizer/output/TwoChannelOutputProcessor.java

@@ -16,29 +16,18 @@
 package io.github.dsheirer.dsp.filter.channelizer.output;
 
 import io.github.dsheirer.dsp.filter.channelizer.TwoChannelSynthesizerM2;
-import io.github.dsheirer.dsp.filter.design.FilterDesignException;
-import io.github.dsheirer.dsp.filter.fir.FIRFilterSpecification;
-import io.github.dsheirer.dsp.filter.fir.complex.ComplexFIRFilter2;
-import io.github.dsheirer.dsp.filter.fir.remez.RemezFIRFilterDesigner;
 import io.github.dsheirer.dsp.mixer.FS4DownConverter;
 import io.github.dsheirer.sample.buffer.ReusableChannelResultsBuffer;
 import io.github.dsheirer.sample.buffer.ReusableComplexBuffer;
 import io.github.dsheirer.sample.buffer.ReusableComplexBufferAssembler;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 
 public class TwoChannelOutputProcessor extends ChannelOutputProcessor
 {
-    private final static Logger mLog = LoggerFactory.getLogger(TwoChannelOutputProcessor.class);
-
-    private static Map<Integer,float[]> sLowPassFilterKernelMap = new HashMap<>();
+//    private final static Logger mLog = LoggerFactory.getLogger(TwoChannelOutputProcessor.class);
     private TwoChannelSynthesizerM2 mSynthesizer;
     private FS4DownConverter mFS4DownConverter = new FS4DownConverter();
-    private ComplexFIRFilter2 mLowPassFilter;
 
     private int mChannelOffset1;
     private int mChannelOffset2;
@@ -58,28 +47,11 @@ public class TwoChannelOutputProcessor extends ChannelOutputProcessor
         super(2, sampleRate, gain);
         setPolyphaseChannelIndices(channelIndexes);
         setSynthesisFilter(filter);
-
-        float[] lowPassFilter = sLowPassFilterKernelMap.get((int)sampleRate);
-
-        if(lowPassFilter == null)
-        {
-            try
-            {
-                lowPassFilter = getLowPassFilter(sampleRate);
-                sLowPassFilterKernelMap.put((int)sampleRate, lowPassFilter);
-            }
-            catch(FilterDesignException fde)
-            {
-                mLog.error("Couldn't design a low-pass filter for 2-channel synthesizer", fde);
-                throw new IllegalStateException("Cannot design low-pass filter for 2 channel synthesizer", fde);
-            }
-        }
-
-        mLowPassFilter = new ComplexFIRFilter2(lowPassFilter, 1.0f);
     }
 
     /**
      * Sets the frequency offset to apply to the incoming samples to mix the desired signal to baseband.
+     *
      * @param frequencyOffset in hertz
      */
     @Override
@@ -126,7 +98,7 @@ public class TwoChannelOutputProcessor extends ChannelOutputProcessor
     public void process(List<ReusableChannelResultsBuffer> channelResultsBuffers,
                         ReusableComplexBufferAssembler reusableComplexBufferAssembler)
     {
-        for(ReusableChannelResultsBuffer buffer: channelResultsBuffers)
+        for(ReusableChannelResultsBuffer buffer : channelResultsBuffers)
         {
             ReusableComplexBuffer channel1 = buffer.getChannel(mChannelOffset1);
             ReusableComplexBuffer channel2 = buffer.getChannel(mChannelOffset2);
@@ -140,48 +112,11 @@ public class TwoChannelOutputProcessor extends ChannelOutputProcessor
             //Apply offset and frequency correction to center the signal of interest within the synthesized channel
             getFrequencyCorrectionMixer().mixComplex(synthesized.getSamples());
 
-            ReusableComplexBuffer lowPassFiltered = mLowPassFilter.filter(synthesized);
+            synthesized.applyGain(getGain());
 
-            lowPassFiltered.applyGain(getGain());
-
-            reusableComplexBufferAssembler.receive(lowPassFiltered);
+            reusableComplexBufferAssembler.receive(synthesized);
 
             buffer.decrementUserCount();
         }
     }
-
-    /**
-     * Creates a low-pass filter kernel for the specified sample rate.
-     * @param sampleRate for the channel
-     * @return filter
-     * @throws FilterDesignException if the filter cannot be designed
-     */
-    private static float[] getLowPassFilter(double sampleRate) throws FilterDesignException
-    {
-        double cutoff = sampleRate / 4.0;
-        int passBandCutoff = (int)(cutoff * 0.92);
-        int stopBandStart = (int)(cutoff * 1.08);
-
-        FIRFilterSpecification specification = FIRFilterSpecification.lowPassBuilder()
-            .sampleRate(sampleRate)
-            .gridDensity(16)
-            .oddLength(true)
-            .passBandCutoff((int)passBandCutoff)
-            .passBandAmplitude(1.0)
-            .passBandRipple(0.01)
-            .stopBandStart((int)stopBandStart)
-            .stopBandAmplitude(0.0)
-            .stopBandRipple(0.005) //Approximately 94 dB attenuation
-            .build();
-
-        RemezFIRFilterDesigner designer = new RemezFIRFilterDesigner(specification);
-
-        if(designer.isValid())
-        {
-            return designer.getImpulseResponse();
-        }
-
-        throw new FilterDesignException("Couldn't design low-pass filter for sample rate: " + sampleRate +
-            " Pass End:" + passBandCutoff + " Stop Begin:" + stopBandStart);
-    }
 }

src/main/java/io/github/dsheirer/dsp/filter/cic/ComplexPrimeCICDecimate.java

@@ -104,7 +104,7 @@ public class ComplexPrimeCICDecimate implements Listener<ReusableComplexBuffer>
      * @throws FilterDesignException if a final low-pass cleanup filter cannot be created for the output channel rate
      *                               and specified pass/stop frequencies.
      */
-    public ComplexPrimeCICDecimate(double sampleRate, int decimation, int passFrequency, int stopFrequency)
+    public ComplexPrimeCICDecimate(double sampleRate, int decimation, double passFrequency, double stopFrequency)
         throws FilterDesignException
     {
         Validate.isTrue(decimation <= PRIMES[PRIMES.length - 1]);
@@ -400,7 +400,7 @@ public class ComplexPrimeCICDecimate implements Listener<ReusableComplexBuffer>
         private ComplexFIRFilter2 mLowPassFilter;
         private Listener<ReusableComplexBuffer> mReusableComplexBufferListener;
 
-        public Output(double outputSampleRate, int passFrequency, int stopFrequency) throws FilterDesignException
+        public Output(double outputSampleRate, double passFrequency, double stopFrequency) throws FilterDesignException
         {
             mBufferAssembler = new ReusableComplexBufferAssembler(2400, outputSampleRate);
 
@@ -461,7 +461,7 @@ public class ComplexPrimeCICDecimate implements Listener<ReusableComplexBuffer>
          * @return a newly designed filter or a previously designed (cached) filter
          * @throws FilterDesignException
          */
-        private float[] getLowPassFilter(double sampleRate, int passFrequency, int stopFrequency) throws FilterDesignException
+        private float[] getLowPassFilter(double sampleRate, double passFrequency, double stopFrequency) throws FilterDesignException
         {
             //Use existing filter if we've already designed one
             if(sLowPassFilters.containsKey((int)sampleRate))

src/main/java/io/github/dsheirer/dsp/filter/design/FilterViewer.java

@@ -1,7 +1,7 @@
 package io.github.dsheirer.dsp.filter.design;
 
-import io.github.dsheirer.dsp.filter.FilterFactory;
 import io.github.dsheirer.dsp.filter.fir.FIRFilterSpecification;
+import io.github.dsheirer.dsp.filter.fir.remez.RemezFIRFilterDesigner;
 import javafx.application.Application;
 import javafx.scene.Scene;
 import javafx.stage.Stage;
@@ -61,14 +61,15 @@ public class FilterViewer extends Application
 //            .passBandRipple(0.01)
 //            .build();
 
-        FIRFilterSpecification specification = FIRFilterSpecification.bandPassBuilder()
-            .sampleRate(8000)
-            .stopFrequency1(1000)
-            .passFrequencyBegin(1100)
-            .passFrequencyEnd(1900)
-            .stopFrequency2(2000)
-            .stopRipple(0.000001)
-            .passRipple(0.00001)
+        FIRFilterSpecification specification = FIRFilterSpecification.lowPassBuilder()
+            .sampleRate(25000.0)
+            .gridDensity(16)
+            .passBandCutoff(11800)
+            .passBandAmplitude(1.0)
+            .passBandRipple(0.01)
+            .stopBandStart(12400)
+            .stopBandAmplitude(0.0)
+            .stopBandRipple(0.01)
             .build();
 
         float[] taps = null;
@@ -81,37 +82,25 @@ public class FilterViewer extends Application
 //        catch(FilterDesignException fde)
 //        {
 //            mLog.error("Error");
-//        }
-
-//        try
-//        {
-//            RemezFIRFilterDesigner designer = new RemezFIRFilterDesigner(specification);
-//
-//            if(designer.isValid())
-//            {
-//                taps = designer.getImpulseResponse();
-//            }
-//        }
-//        catch(FilterDesignException fde)
-//        {
-//            mLog.error("Filter design error", fde);
-//        }
-//
-//        if(taps == null)
-//        {
-//            throw new IllegalStateException("Couldn't design filter");
 //        }
 
         try
         {
-//            taps = FilterFactory.getSincM2Synthesizer(0.25, 2, 9);
-//            taps = FilterFactory.getSincM2Channelizer(12500.0, 2, 9, true);
-            taps = FilterFactory.getSincM2Synthesizer( 25000.0, 12500.0, 2, 9);
+            RemezFIRFilterDesigner designer = new RemezFIRFilterDesigner(specification);
 
+            if(designer.isValid())
+            {
+                taps = designer.getImpulseResponse();
+            }
         }
-        catch(FilterDesignException e)
+        catch(FilterDesignException fde)
         {
-            e.printStackTrace();
+            mLog.error("Filter design error", fde);
+        }
+
+        if(taps == null)
+        {
+            throw new IllegalStateException("Couldn't design filter");
         }
 
         return taps;

src/main/java/io/github/dsheirer/dsp/filter/fir/FIRFilterSpecification.java

@@ -299,8 +299,8 @@ public class FIRFilterSpecification
         private int mOrder;
         private Boolean mOddLength;
         private int mGridDensity = 16;
-        private int mPassBandEndFrequency;
-        private int mStopBandStartFrequency;
+        private double mPassBandEndFrequency;
+        private double mStopBandStartFrequency;
         private double mPassBandRipple;
         private double mStopBandRipple;
         private double mPassBandAmplitude = 1.0;
@@ -342,13 +342,13 @@ public class FIRFilterSpecification
             return this;
         }
 
-        public LowPassBuilder passBandCutoff(int frequencyHz)
+        public LowPassBuilder passBandCutoff(double frequencyHz)
         {
             mPassBandEndFrequency = frequencyHz;
             return this;
         }
 
-        public LowPassBuilder stopBandStart(int frequencyHz)
+        public LowPassBuilder stopBandStart(double frequencyHz)
         {
             mStopBandStartFrequency = frequencyHz;
             return this;
@@ -905,7 +905,7 @@ public class FIRFilterSpecification
      * @param stopBandRipple stop band ripple in dB
      * @return estimated filter length
      */
-    public static int estimateFilterOrder(double sampleRate, int frequency1, int frequency2,
+    public static int estimateFilterOrder(double sampleRate, double frequency1, double frequency2,
                                           double passBandRipple, double stopBandRipple)
     {
         double df = Math.abs(frequency2 - frequency1) / sampleRate;
@@ -1013,13 +1013,13 @@ public class FIRFilterSpecification
          * @param amplitude of the frequency band relative to unity (0.0 - 1.0)
          * @param ripple of the frequency band specified as db ripple
          */
-        public FrequencyBand(double sampleRate, int start, int end, double amplitude, double ripple)
+        public FrequencyBand(double sampleRate, double start, double end, double amplitude, double ripple)
         {
-            this((double)start / sampleRate, (double)end / sampleRate,
+            this(start / sampleRate, end / sampleRate,
                 amplitude, ripple);
         }
 
-        public FrequencyBand(double sampleRate, int start, int end, double amplitude, double ripple, double weight)
+        public FrequencyBand(double sampleRate, double start, double end, double amplitude, double ripple, double weight)
         {
             this(sampleRate, start, end, amplitude, ripple);
             mWeight = weight;

src/main/java/io/github/dsheirer/dsp/psk/DQPSKDecisionDirectedSymbolEvaluator.java

@@ -95,10 +95,45 @@ public class DQPSKDecisionDirectedSymbolEvaluator implements IPSKSymbolEvaluator
 
         //Since we've rotated the error symbol back to 0 radians, the quadrature value closely approximates the
         //arctan of the error angle relative to 0 radians and this provides our error value
-        mPhaseError = -mEvaluationSymbol.quadrature();
+        float errorNormalized = normalize(mEvaluationSymbol.quadrature(), 0.3f);
+
+        mPhaseError = -errorNormalized;
 
         //Timing error is the same as phase error with the sign corrected according to the vector's angular rotation
-        mTimingError = mEvaluationSymbol.quadrature() * mTimingErrorPolarity;
+        mTimingError = errorNormalized * mTimingErrorPolarity;
+    }
+
+    /**
+     * Constrains value to the range of ( -maximum <> maximum )
+     */
+    private static float clip(float value, float maximum)
+    {
+        if(value > maximum)
+        {
+            return maximum;
+        }
+        else if(value < -maximum)
+        {
+            return -maximum;
+        }
+
+        return value;
+    }
+
+    /**
+     * Constrains timing error to +/- the maximum value and corrects any
+     * floating point invalid numbers
+     */
+    private float normalize(float error, float maximum)
+    {
+        if(Float.isNaN(error))
+        {
+            return 0.0f;
+        }
+        else
+        {
+            return clip(error, maximum);
+        }
     }
 
     /**

src/main/java/io/github/dsheirer/dsp/psk/DQPSKGardnerSymbolEvaluator.java

@@ -100,7 +100,7 @@ public class DQPSKGardnerSymbolEvaluator implements IPSKSymbolEvaluator<Dibit>
 
         //Since we've rotated the error symbol back to 0 radians, the quadrature value closely approximates the
         //arctan of the error angle relative to 0 radians and this provides our error value
-        mPhaseError = -mEvaluationSymbol.quadrature();
+        mPhaseError = normalize(-mEvaluationSymbol.quadrature(), 0.3f);
     }
 
     /**

src/main/java/io/github/dsheirer/dsp/psk/pll/PLLGain.java

@@ -20,11 +20,13 @@ package io.github.dsheirer.dsp.psk.pll;
  */
 public enum PLLGain
 {
-    LEVEL_1(50.0, 0, 1),
-    LEVEL_2(75.0, 2, 4),
-    LEVEL_3(100.0, 5, 6),
-    LEVEL_4(125.0, 7, 8),
-    LEVEL_5(150.0, 9, 10);
+    //NOTE: static gain level of 200 produced the best results for releases prior to 0.3.4b2
+
+    LEVEL_1(150.0, 0, 1),
+    LEVEL_2(170.0, 2, 4),
+    LEVEL_3(190.0, 5, 6),
+    LEVEL_4(200.0, 7, 8),
+    LEVEL_5(200.0, 9, 10);
 
     private double mLoopBandwidth;
     private int mRangeStart;

src/main/java/io/github/dsheirer/gui/channelizer/ChannelizerViewer.java

@@ -260,7 +260,7 @@ public class ChannelizerViewer extends JFrame
             for(int x = 0; x < mChannelCount; x++)
             {
                 TunerChannel tunerChannel = new TunerChannel(100000000, 12500);
-                TunerChannelSource source = mTestTuner.getChannelSourceManager().getSource(tunerChannel);
+                TunerChannelSource source = mTestTuner.getChannelSourceManager().getSource(tunerChannel, null);
                 DiscreteChannelPanel channelPanel = new DiscreteChannelPanel(mSettingsManager, source, x);
                 channelPanel.setDFTSize(mChannelPanelDFTSize);
 
@@ -362,7 +362,7 @@ public class ChannelizerViewer extends JFrame
             mComplexDecibelConverter.addListener(mSpectrumPanel);
 
             TunerChannel tunerChannel = new TunerChannel(frequency, bandwidth);
-            mSource = mTestTuner.getChannelSourceManager().getSource(tunerChannel);
+            mSource = mTestTuner.getChannelSourceManager().getSource(tunerChannel, null);
 
             if(mSource != null)
             {
@@ -556,7 +556,7 @@ public class ChannelizerViewer extends JFrame
             {
                 if(sourceCount < maxSourceCount)
                 {
-                    TunerChannelSource source = tuner.getChannelSourceManager().getSource(tunerChannel);
+                    TunerChannelSource source = tuner.getChannelSourceManager().getSource(tunerChannel, null);
 
                     if(source != null)
                     {

src/main/java/io/github/dsheirer/gui/channelizer/ChannelizerViewer2.java

@@ -23,6 +23,7 @@ import io.github.dsheirer.source.ISourceEventProcessor;
 import io.github.dsheirer.source.SourceEvent;
 import io.github.dsheirer.source.SourceException;
 import io.github.dsheirer.source.tuner.Tuner;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 import io.github.dsheirer.source.tuner.channel.TunerChannel;
 import io.github.dsheirer.source.tuner.channel.TunerChannelSource;
 import io.github.dsheirer.source.tuner.configuration.TunerConfigurationModel;
@@ -376,10 +377,11 @@ public class ChannelizerViewer2 extends JFrame
             mComplexDecibelConverter.addListener(mSpectrumPanel);
 
             TunerChannel tunerChannel = new TunerChannel(frequency, bandwidth);
-            mSource = mTestTuner.getChannelSourceManager().getSource(tunerChannel);
+            mSource = mTestTuner.getChannelSourceManager().getSource(tunerChannel, new ChannelSpecification(50000, 12500, 6000, 7000));
 
             if(mSource != null)
             {
+                mLog.debug("Channel: " + mSource.getTunerChannel() + " Rate:" + mSource.getSampleRate());
                 mSource.setListener(new Listener<ReusableComplexBuffer>()
                 {
                     @Override

src/main/java/io/github/dsheirer/gui/instrument/DemodulatorViewerFX.java

@@ -34,6 +34,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.File;
+import java.util.prefs.Preferences;
 
 /**
  * Application for viewing and working with demodulators and recording files.
@@ -42,6 +43,9 @@ public class DemodulatorViewerFX extends Application
 {
     private final static Logger mLog = LoggerFactory.getLogger(DemodulatorViewerFX.class);
 
+    private static final String PREFERENCE_FILE_OPEN_DEFAULT_FOLDER = "default.folder";
+
+    private Preferences mPreferences = Preferences.userNodeForPackage(DemodulatorViewerFX.class);
     private Stage mStage;
     private MenuBar mMenuBar;
     private RecentFilesMenu mRecentFilesMenu;
@@ -117,9 +121,22 @@ public class DemodulatorViewerFX extends Application
                 {
                     FileChooser fileChooser = new FileChooser();
                     fileChooser.setTitle("Open an I/Q recording file");
+
+                    String directory = mPreferences.get(PREFERENCE_FILE_OPEN_DEFAULT_FOLDER, null);
+
+                    if(directory != null)
+                    {
+                        fileChooser.setInitialDirectory(new File(directory));
+                    }
+
                     File file = fileChooser.showOpenDialog(mStage);
-                    getViewerDesktop().load(file);
-                    getRecentFilesMenu().add(file);
+
+                    if(file != null)
+                    {
+                        getViewerDesktop().load(file);
+                        getRecentFilesMenu().add(file);
+                        mPreferences.put(PREFERENCE_FILE_OPEN_DEFAULT_FOLDER, file.getParent());
+                    }
                 }
             });
 

src/main/java/io/github/dsheirer/gui/instrument/RecentFilesMenu.java

@@ -26,6 +26,7 @@ import java.util.prefs.Preferences;
 
 public class RecentFilesMenu extends Menu implements EventHandler<ActionEvent>
 {
+    private static final String PREFERENCE_RECENT_FILE = ".recent.file.";
     private Preferences mPreferences = Preferences.userNodeForPackage(RecentFilesMenu.class);
     private IFileSelectionListener mFileSelectionListener;
     private String mIdentifier;
@@ -111,7 +112,7 @@ public class RecentFilesMenu extends Menu implements EventHandler<ActionEvent>
      */
     private String getKey(int index)
     {
-        return mIdentifier + ".recent.file." + index;
+        return mIdentifier + PREFERENCE_RECENT_FILE + index;
     }
 
     /**

src/main/java/io/github/dsheirer/gui/instrument/chart/DoubleLineChart.java

@@ -21,6 +21,7 @@ import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
 import javafx.scene.chart.LineChart;
 import javafx.scene.chart.NumberAxis;
+import javafx.scene.chart.ValueAxis;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -42,6 +43,24 @@ public class DoubleLineChart extends LineChart implements Listener<Double>
         init(length);
     }
 
+    /**
+     * Sets the minimum displayable value for the y axis
+     * @param min
+     */
+    public void setMin(double min)
+    {
+        ((ValueAxis)getYAxis()).setLowerBound(min);
+    }
+
+    /**
+     * Sets the maximum displayable value for the y axis
+     * @param max
+     */
+    public void setMax(double max)
+    {
+        ((ValueAxis)getYAxis()).setUpperBound(max);
+    }
+
     private void init(int length)
     {
         mDoubleCircularBuffer = new DoubleCircularBuffer(length);

src/main/java/io/github/dsheirer/gui/instrument/chart/SamplesPerSymbolChart.java

@@ -0,0 +1,59 @@
+/*******************************************************************************
+ * sdr-trunk
+ * Copyright (C) 2014-2018 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 io.github.dsheirer.gui.instrument.chart;
+
+import javafx.collections.ObservableList;
+
+public class SamplesPerSymbolChart extends DoubleLineChart
+{
+    private double mFractionalSamplesPerSymbol;
+    private double mPreviousSamplesPerSymbol;
+
+    public SamplesPerSymbolChart(int length, double samplesPerSymbol)
+    {
+        super("Samples Per Symbol", -1.0, 1.0, 0.1, length);
+        setSamplesPerSymbol(samplesPerSymbol);
+    }
+
+    public void setSamplesPerSymbol(double samplesPerSymbol)
+    {
+        mFractionalSamplesPerSymbol = samplesPerSymbol - ((int)samplesPerSymbol);
+        mPreviousSamplesPerSymbol = samplesPerSymbol;
+
+        ObservableList<Series> seriesList = getData();
+        seriesList.get(0).setName("Samples Per Symbol:" + samplesPerSymbol);
+    }
+
+    @Override
+    public void receive(Double samplesPerSymbol)
+    {
+        double delta = samplesPerSymbol - mPreviousSamplesPerSymbol - mFractionalSamplesPerSymbol;
+
+        while(delta < (-1.0 + mFractionalSamplesPerSymbol))
+        {
+            delta++;
+        }
+
+        while(delta > 1.0)
+        {
+            delta--;
+        }
+
+        super.receive(delta);
+
+        mPreviousSamplesPerSymbol = samplesPerSymbol;
+    }
+}

src/main/java/io/github/dsheirer/gui/instrument/decoder/P25Phase1LSMPane.java

@@ -19,6 +19,7 @@ import io.github.dsheirer.gui.instrument.chart.ComplexSampleLineChart;
 import io.github.dsheirer.gui.instrument.chart.DoubleLineChart;
 import io.github.dsheirer.gui.instrument.chart.EyeDiagramChart;
 import io.github.dsheirer.gui.instrument.chart.PhaseLineChart;
+import io.github.dsheirer.gui.instrument.chart.SamplesPerSymbolChart;
 import io.github.dsheirer.gui.instrument.chart.SymbolChart;
 import io.github.dsheirer.message.Message;
 import io.github.dsheirer.module.decode.DecoderType;
@@ -34,14 +35,14 @@ public class P25Phase1LSMPane extends ComplexDecoderPane
 {
     private final static Logger mLog = LoggerFactory.getLogger(P25Phase1LSMPane.class);
 
-    private HBox mSampleChartBox;
-    private ComplexSampleLineChart mSampleLineChart;
+    private HBox mTopChartBox;
+    private ComplexSampleLineChart mDifferentialDemodulatedSamplesChartBox;
     private EyeDiagramChart mEyeDiagramChart;
-    private HBox mDecoderChartBox;
-    private SymbolChart mSymbolChart;
+    private HBox mBottomChartBox;
+    private SymbolChart mSymbolConstellationChart;
     private PhaseLineChart mPLLPhaseErrorLineChart;
     private DoubleLineChart mPLLFrequencyLineChart;
-    private DoubleLineChart mSamplesPerSymbolLineChart;
+    private SamplesPerSymbolChart mSamplesPerSymbolLineChart;
     private ReusableBufferBroadcaster mFilteredBufferBroadcaster = new ReusableBufferBroadcaster();
     private P25DecoderLSMInstrumented mDecoder = new P25DecoderLSMInstrumented(null);
 
@@ -56,16 +57,16 @@ public class P25Phase1LSMPane extends ComplexDecoderPane
         addListener(getDecoder());
 
         getDecoder().setFilteredBufferListener(mFilteredBufferBroadcaster);
-        getDecoder().setComplexSymbolListener(getSymbolChart());
+        getDecoder().setComplexSymbolListener(getSymbolConstellationChart());
         getDecoder().setPLLPhaseErrorListener(getPLLPhaseErrorLineChart());
         getDecoder().setPLLFrequencyListener(getPLLFrequencyLineChart());
         getDecoder().setSymbolDecisionDataListener(getEyeDiagramChart());
         getDecoder().setSamplesPerSymbolListener(getSamplesPerSymbolLineChart());
-        mFilteredBufferBroadcaster.addListener(getSampleLineChart());
+        mFilteredBufferBroadcaster.addListener(getDifferentialDemodulatedSamplesChartBox());
 
-        HBox.setHgrow(getSampleChartBox(), Priority.ALWAYS);
-        HBox.setHgrow(getDecoderChartBox(), Priority.ALWAYS);
-        getChildren().addAll(getSampleChartBox(), getDecoderChartBox());
+        HBox.setHgrow(getTopChartBox(), Priority.ALWAYS);
+        HBox.setHgrow(getBottomChartBox(), Priority.ALWAYS);
+        getChildren().addAll(getTopChartBox(), getBottomChartBox());
 
         mDecoder.setMessageListener(new Listener<Message>()
         {
@@ -86,7 +87,8 @@ public class P25Phase1LSMPane extends ComplexDecoderPane
         mDecoder.setSampleRate(sampleRate);
         double samplesPerSymbol = sampleRate / 4800.0;
 
-        getSampleLineChart().setSamplesPerSymbol((int)samplesPerSymbol);
+        getDifferentialDemodulatedSamplesChartBox().setSamplesPerSymbol((int)samplesPerSymbol);
+        getSamplesPerSymbolLineChart().setSamplesPerSymbol(samplesPerSymbol);
     }
 
     private P25DecoderLSMInstrumented getDecoder()
@@ -94,69 +96,69 @@ public class P25Phase1LSMPane extends ComplexDecoderPane
         return mDecoder;
     }
 
-    private SymbolChart getSymbolChart()
+    private SymbolChart getSymbolConstellationChart()
     {
-        if(mSymbolChart == null)
+        if(mSymbolConstellationChart == null)
         {
-            mSymbolChart = new SymbolChart(10);
+            mSymbolConstellationChart = new SymbolChart(10);
         }
 
-        return mSymbolChart;
+        return mSymbolConstellationChart;
     }
 
-    private HBox getDecoderChartBox()
+    private HBox getBottomChartBox()
     {
-        if(mDecoderChartBox == null)
+        if(mBottomChartBox == null)
         {
-            mDecoderChartBox = new HBox();
-            mDecoderChartBox.setMaxHeight(Double.MAX_VALUE);
-            getSymbolChart().setMaxWidth(Double.MAX_VALUE);
+            mBottomChartBox = new HBox();
+            mBottomChartBox.setMaxHeight(Double.MAX_VALUE);
+            getSymbolConstellationChart().setMaxWidth(Double.MAX_VALUE);
             getPLLPhaseErrorLineChart().setMaxWidth(Double.MAX_VALUE);
             getPLLFrequencyLineChart().setMaxWidth(Double.MAX_VALUE);
-            HBox.setHgrow(getSymbolChart(), Priority.ALWAYS);
+            HBox.setHgrow(getSymbolConstellationChart(), Priority.ALWAYS);
             HBox.setHgrow(getPLLPhaseErrorLineChart(), Priority.ALWAYS);
             HBox.setHgrow(getPLLFrequencyLineChart(), Priority.ALWAYS);
-            mDecoderChartBox.getChildren().addAll(getSymbolChart(), getPLLPhaseErrorLineChart(),
+            mBottomChartBox.getChildren().addAll(getSymbolConstellationChart(), getPLLPhaseErrorLineChart(),
                 getPLLFrequencyLineChart());
         }
 
-        return mDecoderChartBox;
+        return mBottomChartBox;
     }
 
-    private HBox getSampleChartBox()
+    private HBox getTopChartBox()
     {
-        if(mSampleChartBox == null)
+        if(mTopChartBox == null)
         {
-            mSampleChartBox = new HBox();
-            mSampleChartBox.setMaxHeight(Double.MAX_VALUE);
-            getSampleLineChart().setMaxWidth(Double.MAX_VALUE);
+            mTopChartBox = new HBox();
+            mTopChartBox.setMaxHeight(Double.MAX_VALUE);
+            getDifferentialDemodulatedSamplesChartBox().setMaxWidth(Double.MAX_VALUE);
             getEyeDiagramChart().setMaxWidth(Double.MAX_VALUE);
             getSamplesPerSymbolLineChart().setMaxWidth(Double.MAX_VALUE);
-            HBox.setHgrow(getSampleLineChart(), Priority.ALWAYS);
+            HBox.setHgrow(getDifferentialDemodulatedSamplesChartBox(), Priority.ALWAYS);
             HBox.setHgrow(getEyeDiagramChart(), Priority.ALWAYS);
             HBox.setHgrow(getSamplesPerSymbolLineChart(), Priority.ALWAYS);
-            mSampleChartBox.getChildren().addAll(getSampleLineChart(), getEyeDiagramChart(),
+            mTopChartBox.getChildren().addAll(getDifferentialDemodulatedSamplesChartBox(), getEyeDiagramChart(),
                 getSamplesPerSymbolLineChart());
         }
 
-        return mSampleChartBox;
+        return mTopChartBox;
     }
 
-    private ComplexSampleLineChart getSampleLineChart()
+    private ComplexSampleLineChart getDifferentialDemodulatedSamplesChartBox()
     {
-        if(mSampleLineChart == null)
+        if(mDifferentialDemodulatedSamplesChartBox == null)
         {
-            mSampleLineChart = new ComplexSampleLineChart(100, 10);
+            mDifferentialDemodulatedSamplesChartBox = new ComplexSampleLineChart(100, 10);
         }
 
-        return mSampleLineChart;
+        return mDifferentialDemodulatedSamplesChartBox;
     }
 
     private EyeDiagramChart getEyeDiagramChart()
     {
         if(mEyeDiagramChart == null)
         {
-            mEyeDiagramChart = new EyeDiagramChart(10, "Middle: 3-4 / Symbol: 8-9");
+            mEyeDiagramChart = new EyeDiagramChart(10, "Symbol/Eye Diagram");
         }
 
         return mEyeDiagramChart;
@@ -182,11 +184,11 @@ public class P25Phase1LSMPane extends ComplexDecoderPane
         return mPLLFrequencyLineChart;
     }
 
-    private DoubleLineChart getSamplesPerSymbolLineChart()
+    private SamplesPerSymbolChart getSamplesPerSymbolLineChart()
     {
         if(mSamplesPerSymbolLineChart == null)
         {
-            mSamplesPerSymbolLineChart = new DoubleLineChart( "Sample Point", 4.5, 7.0, 0.1, 40);
+            mSamplesPerSymbolLineChart = new SamplesPerSymbolChart(40, 6.25);
         }
 
         return mSamplesPerSymbolLineChart;

src/main/java/io/github/dsheirer/module/ProcessingChain.java

@@ -565,12 +565,6 @@ public class ProcessingChain implements IChannelEventListener
         {
             if(mSource != null)
             {
-                //Reset each of the modules
-                for(Module module : mModules)
-                {
-                    module.reset();
-                }
-
                 //Broadcast the source sample rate so that each of the modules can self-configure
                 mSourceEventBroadcaster.broadcast(SourceEvent.sampleRateChange(mSource.getSampleRate(), "Processing Chain Startup"));
 
@@ -652,6 +646,12 @@ public class ProcessingChain implements IChannelEventListener
             {
                 module.stop();
             }
+
+            //Reset each of the modules
+            for(Module module : mModules)
+            {
+                module.reset();
+            }
         }
     }
 

src/main/java/io/github/dsheirer/module/decode/DecoderFactory.java

@@ -347,7 +347,6 @@ public class DecoderFactory
                 filters.add(new MPT1327MessageFilter());
                 break;
             case P25_PHASE1:
-            case P25_PHASE2:
                 filters.add(new P25MessageFilterSet());
                 break;
             case PASSPORT:

src/main/java/io/github/dsheirer/module/decode/DecoderType.java

@@ -1,19 +1,17 @@
 /*******************************************************************************
- *     SDR Trunk 
- *     Copyright (C) 2014 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/>
+ * sdr-trunk
+ * Copyright (C) 2014-2018 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 io.github.dsheirer.module.decode;
 
@@ -25,37 +23,28 @@ import java.util.EnumSet;
  */
 public enum DecoderType
 {
-	ACARS( "ACARS", "ACARS", "images/acars.png", 12500 ),
-	AIS( "AIS", "AIS", "images/ais.png", 12500 ),
-    AM( "AM", "AM", "images/am.png", 10000 ),
-    APRS( "APRS", "APRS", "images/aprs.png", 12500 ),
-    DMR( "DMR", "DMR", "images/dmr.png", 12500 ),
-    FLEETSYNC2( "Fleetsync II", "Fleetsync2", "images/fm.png", 12500 ),
-    LJ_1200( "LJ1200 173.075", "LJ1200", "images/lj1200.png", 12500 ),
-    LTR_STANDARD( "LTR-Standard", "LTR", "images/ltr.png", 10000 ),
-    LTR_NET( "LTR-Net", "LTR-Net", "images/ltr_net.png", 12500 ),
-    MDC1200( "MDC1200", "MDC1200", "images/fm.png", 12500 ),
-    MOTOROLA_TYPE_2( "MOTO T2", "MOTO T2", "images/motorola_type_2.png", 15000 ),
-    MPT1327( "MPT1327", "MPT1327", "images/mpt1327.png", 12500 ),
-    NXDN( "NXDN", "NXDN", "images/nxdn.png", 8000 ),
-    NBFM( "NBFM", "NBFM", "images/fm.png", 12500 ),
-    PASSPORT( "Passport", "Passport", "images/passport.png", 12500 ),
-    P25_PHASE1( "P25 Phase I", "P25-1", "images/p25_1.png", 12500 ),
-    P25_PHASE2( "P25 Phase II", "P25-2", "images/p25_2.png", 15000 ),
-    TAIT_1200( "Tait 1200", "Tait 1200", "images/tait.png", 12500 );
-    
+    //Primary Decoders
+    AM("AM", "AM"),
+    LTR_STANDARD("LTR-Standard", "LTR"),
+    LTR_NET("LTR-Net", "LTR-Net"),
+    MPT1327("MPT1327", "MPT1327"),
+    NBFM("NBFM", "NBFM"),
+    PASSPORT("Passport", "Passport"),
+    P25_PHASE1("P25 Phase I", "P25-1"),
+
+    //Auxiliary Decoders
+    FLEETSYNC2("Fleetsync II", "Fleetsync2"),
+    LJ_1200("LJ1200 173.075", "LJ1200"),
+    MDC1200("MDC1200", "MDC1200"),
+    TAIT_1200("Tait 1200", "Tait 1200");
+
     private String mDisplayString;
     private String mShortDisplayString;
-    private String mIconFilename;
-    private int mChannelBandwidth;
-    
-    DecoderType( String displayString, String shortDisplayString, 
-    			 String iconFilename, int bandwidth )
+
+    DecoderType(String displayString, String shortDisplayString)
     {
         mDisplayString = displayString;
         mShortDisplayString = shortDisplayString;
-        mIconFilename = iconFilename;
-        mChannelBandwidth = bandwidth;
     }
 
     /**
@@ -63,68 +52,43 @@ public enum DecoderType
      */
     public static EnumSet<DecoderType> getPrimaryDecoders()
     {
-    	return EnumSet.of( DecoderType.AM,
-    	                   DecoderType.LTR_NET,
-    					   DecoderType.LTR_STANDARD,
-    					   DecoderType.MPT1327,
-    					   DecoderType.NBFM,
-    					   DecoderType.P25_PHASE1,
-    					   DecoderType.PASSPORT );
+        return EnumSet.of(DecoderType.AM,
+            DecoderType.LTR_NET,
+            DecoderType.LTR_STANDARD,
+            DecoderType.MPT1327,
+            DecoderType.NBFM,
+            DecoderType.P25_PHASE1,
+            DecoderType.PASSPORT);
     }
 
-    /**
-     * Decoders that can be used in the viewer application
-     */
-    public static EnumSet<DecoderType> getInstrumentableDecoders()
-    {
-    	return EnumSet.of( DecoderType.FLEETSYNC2,
-    				 	   DecoderType.LJ_1200,
-    	                   DecoderType.LTR_NET,
-    					   DecoderType.MDC1200,
-    					   DecoderType.MPT1327,
-    					   DecoderType.PASSPORT,
-    					   DecoderType.P25_PHASE1,
-    					   DecoderType.TAIT_1200 );
-    }
-    
     /**
      * Available auxiliary decoders.
      */
     public static ArrayList<DecoderType> getAuxDecoders()
     {
-    	ArrayList<DecoderType> decoders = new ArrayList<DecoderType>();
-    	
-    	decoders.add( DecoderType.FLEETSYNC2 );
-    	decoders.add( DecoderType.LJ_1200 );
-    	decoders.add( DecoderType.MDC1200 );
-    	decoders.add( DecoderType.TAIT_1200 );
-    	
-    	return decoders;
+        ArrayList<DecoderType> decoders = new ArrayList<DecoderType>();
+
+        decoders.add(DecoderType.FLEETSYNC2);
+        decoders.add(DecoderType.LJ_1200);
+        decoders.add(DecoderType.MDC1200);
+        decoders.add(DecoderType.TAIT_1200);
+
+        return decoders;
     }
-    
+
     public String getDisplayString()
     {
         return mDisplayString;
     }
-    
+
     public String getShortDisplayString()
     {
-    	return mShortDisplayString;
+        return mShortDisplayString;
     }
-    
-    public String getIconFilename()
-    {
-    	return mIconFilename;
-    }
-    
-    public int getChannelBandwidth()
-    {
-    	return mChannelBandwidth;
-    }
-    
+
     @Override
     public String toString()
     {
-    	return mDisplayString;
+        return mDisplayString;
     }
 }

src/main/java/io/github/dsheirer/module/decode/am/DecodeConfigAM.java

@@ -17,9 +17,11 @@
  ******************************************************************************/
 package io.github.dsheirer.module.decode.am;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
 import io.github.dsheirer.module.decode.DecoderType;
 import io.github.dsheirer.module.decode.config.DecodeConfiguration;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 
 public class DecodeConfigAM extends DecodeConfiguration
 {
@@ -27,6 +29,17 @@ public class DecodeConfigAM extends DecodeConfiguration
     {
     }
 
+    /**
+     * Source channel specification for this decoder
+     */
+    @JsonIgnore
+    @Override
+    public ChannelSpecification getChannelSpecification()
+    {
+        return new ChannelSpecification(25000.0,
+            3000, 3000.0, 5000.0);
+    }
+
     @JacksonXmlProperty(isAttribute = true, localName = "type", namespace = "http://www.w3.org/2001/XMLSchema-instance")
     public DecoderType getDecoderType()
     {

src/main/java/io/github/dsheirer/module/decode/config/DecodeConfiguration.java

@@ -29,6 +29,7 @@ import io.github.dsheirer.module.decode.mpt1327.DecodeConfigMPT1327;
 import io.github.dsheirer.module.decode.nbfm.DecodeConfigNBFM;
 import io.github.dsheirer.module.decode.p25.DecodeConfigP25Phase1;
 import io.github.dsheirer.module.decode.passport.DecodeConfigPassport;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
@@ -58,4 +59,7 @@ public abstract class DecodeConfiguration extends Configuration
 
     @JsonIgnore
     public abstract DecoderType getDecoderType();
+
+    @JsonIgnore
+    public abstract ChannelSpecification getChannelSpecification();
 }

src/main/java/io/github/dsheirer/module/decode/event/MessageActivityPanel.java

@@ -30,10 +30,17 @@ import net.miginfocom.swing.MigLayout;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import javax.swing.*;
+import javax.swing.JButton;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JPanel;
+import javax.swing.JScrollPane;
+import javax.swing.JSlider;
+import javax.swing.JTable;
+import javax.swing.SwingUtilities;
 import javax.swing.event.ChangeEvent;
 import javax.swing.event.ChangeListener;
-import java.awt.*;
+import java.awt.EventQueue;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 import java.awt.event.MouseEvent;
@@ -86,64 +93,6 @@ public class MessageActivityPanel extends JPanel implements Listener<ProcessingC
         });
     }
 
-    //    @Override
-//    public void channelChanged(ChannelEvent event)
-//    {
-//        boolean changed = false;
-//
-//        if(event.getEvent() == Event.NOTIFICATION_SELECTION_CHANGE &&
-//            event.getChannel().isSelected())
-//        {
-//            if(mDisplayedChannel == null || (mDisplayedChannel != null && mDisplayedChannel != event.getChannel()))
-//            {
-//                mDisplayedChannel = event.getChannel();
-//
-//                ProcessingChain chain = mChannelProcessingManager.getProcessingChain(mDisplayedChannel);
-//
-//                if(chain != null)
-//                {
-//                    mDisplayedModel = chain.getMessageActivityModel();
-//                }
-//                else
-//                {
-//                    mDisplayedModel = EMPTY_MODEL;
-//                }
-//
-//                mMessageTable.setModel(mDisplayedModel);
-//
-//                if(mDisplayedChannel != null)
-//                {
-//                    mManagementPanel.enableButtons();
-//                }
-//                else
-//                {
-//                    mManagementPanel.disableButtons();
-//                }
-//
-//                changed = true;
-//            }
-//        }
-//        else if(event.getEvent() == Event.NOTIFICATION_PROCESSING_STOP || event.getEvent() == Event.REQUEST_DISABLE)
-//        {
-//            if(mDisplayedChannel != null && mDisplayedChannel == event.getChannel())
-//            {
-//                mDisplayedChannel = null;
-//
-//                mMessageTable.setModel(EMPTY_MODEL);
-//
-//                mManagementPanel.disableButtons();
-//
-//                changed = true;
-//            }
-//        }
-//
-//        if(changed)
-//        {
-//            revalidate();
-//            repaint();
-//        }
-//    }
-
     public class MessageManagementPanel extends JPanel
     {
         private static final long serialVersionUID = 1L;

src/main/java/io/github/dsheirer/module/decode/ltrnet/DecodeConfigLTRNet.java

@@ -17,10 +17,12 @@
  ******************************************************************************/
 package io.github.dsheirer.module.decode.ltrnet;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
 import io.github.dsheirer.message.MessageDirection;
 import io.github.dsheirer.module.decode.DecoderType;
 import io.github.dsheirer.module.decode.config.DecodeConfiguration;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 
 public class DecodeConfigLTRNet extends DecodeConfiguration
 {
@@ -46,4 +48,15 @@ public class DecodeConfigLTRNet extends DecodeConfiguration
     {
         mMessageDirection = direction;
     }
+
+    /**
+     * Source channel specification for this decoder
+     */
+    @JsonIgnore
+    @Override
+    public ChannelSpecification getChannelSpecification()
+    {
+        return new ChannelSpecification(25000.0,
+            12500, 6000.0, 7000.0);
+    }
 }

src/main/java/io/github/dsheirer/module/decode/ltrstandard/DecodeConfigLTRStandard.java

@@ -17,10 +17,12 @@
  ******************************************************************************/
 package io.github.dsheirer.module.decode.ltrstandard;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
 import io.github.dsheirer.message.MessageDirection;
 import io.github.dsheirer.module.decode.DecoderType;
 import io.github.dsheirer.module.decode.config.DecodeConfiguration;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 
 public class DecodeConfigLTRStandard extends DecodeConfiguration
 {
@@ -47,4 +49,15 @@ public class DecodeConfigLTRStandard extends DecodeConfiguration
     {
         mMessageDirection = direction;
     }
+
+    /**
+     * Source channel specification for this decoder
+     */
+    @JsonIgnore
+    @Override
+    public ChannelSpecification getChannelSpecification()
+    {
+        return new ChannelSpecification(25000.0,
+            12500, 6000.0, 7000.0);
+    }
 }

src/main/java/io/github/dsheirer/module/decode/mpt1327/DecodeConfigMPT1327.java

@@ -17,9 +17,11 @@
  ******************************************************************************/
 package io.github.dsheirer.module.decode.mpt1327;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
 import io.github.dsheirer.module.decode.DecoderType;
 import io.github.dsheirer.module.decode.config.DecodeConfiguration;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 
 public class DecodeConfigMPT1327 extends DecodeConfiguration
 {
@@ -102,4 +104,15 @@ public class DecodeConfigMPT1327 extends DecodeConfiguration
     {
         mTrafficChannelPoolSize = size;
     }
+
+    /**
+     * Source channel specification for this decoder
+     */
+    @JsonIgnore
+    @Override
+    public ChannelSpecification getChannelSpecification()
+    {
+        return new ChannelSpecification(25000.0,
+            12500, 6000.0, 7000.0);
+    }
 }

src/main/java/io/github/dsheirer/module/decode/nbfm/DecodeConfigNBFM.java

@@ -17,12 +17,16 @@
  ******************************************************************************/
 package io.github.dsheirer.module.decode.nbfm;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
 import io.github.dsheirer.module.decode.DecoderType;
 import io.github.dsheirer.module.decode.config.DecodeConfiguration;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 
 public class DecodeConfigNBFM extends DecodeConfiguration
 {
+    private Bandwidth mBandwidth = Bandwidth.BW_12_5;
+
     public DecodeConfigNBFM()
     {
     }
@@ -33,4 +37,53 @@ public class DecodeConfigNBFM extends DecodeConfiguration
         return DecoderType.NBFM;
     }
 
+    /**
+     * Channel bandwidth
+     */
+    @JacksonXmlProperty(isAttribute = true, localName = "bandwidth")
+    public Bandwidth getBandwidth()
+    {
+        return mBandwidth;
+    }
+
+    @JsonIgnore
+    @Override
+    public ChannelSpecification getChannelSpecification()
+    {
+        if(mBandwidth == Bandwidth.BW_12_5)
+        {
+            return new ChannelSpecification(25000.0, 12500, 6000.0, 7000.0);
+        }
+        else
+        {
+            return new ChannelSpecification(50000.0, 25000, 12500.0, 13500.0);
+        }
+    }
+
+    /**
+     * Sets the channel bandwidth
+     */
+    public void setBandwidth(Bandwidth bandwidth)
+    {
+        mBandwidth = bandwidth;
+    }
+
+    public enum Bandwidth
+    {
+        BW_12_5("12.5 kHz"),
+        BW_25_0("25.0 kHz");
+
+        private String mLabel;
+
+        Bandwidth(String label)
+        {
+            mLabel = label;
+        }
+
+        @Override
+        public String toString()
+        {
+            return mLabel;
+        }
+    };
 }

src/main/java/io/github/dsheirer/module/decode/nbfm/NBFMDecoderEditor.java

@@ -1,19 +1,17 @@
 /*******************************************************************************
- *     SDR Trunk 
- *     Copyright (C) 2014-2016 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/>
+ * sdr-trunk
+ * Copyright (C) 2014-2018 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 io.github.dsheirer.module.decode.nbfm;
 
@@ -24,70 +22,94 @@ import io.github.dsheirer.gui.editor.ValidatingEditor;
 import io.github.dsheirer.module.decode.config.DecodeConfiguration;
 import net.miginfocom.swing.MigLayout;
 
+import javax.swing.DefaultComboBoxModel;
+import javax.swing.JComboBox;
 import javax.swing.JLabel;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
 
 public class NBFMDecoderEditor extends ValidatingEditor<Channel>
 {
     private static final long serialVersionUID = 1L;
-    
-	public NBFMDecoderEditor()
-	{
-		init();
-	}
-	
-	private void init()
-	{
-		setLayout( new MigLayout( "insets 0 0 0 0,wrap 2", "[right][grow,fill]", "" ) );
-		add( new JLabel( "Narrow Band FM Decoder" ) );
-	}
 
-	@Override
-	public void validate( Editor<Channel> editor ) throws EditorValidationException
-	{
-		//No validation
-	}
+    private JComboBox<DecodeConfigNBFM.Bandwidth> mComboBandwidth;
 
-	@Override
-	public void save()
-	{
-		if( hasItem() && isModified() )
-		{
-			DecodeConfigNBFM nbfm = new DecodeConfigNBFM();
-			getItem().setDecodeConfiguration( nbfm );
-		}
-		
-		setModified( false );
-	}
+    public NBFMDecoderEditor()
+    {
+        init();
+    }
 
-	private void setControlsEnabled( boolean enabled )
-	{
-	}
+    private void init()
+    {
+        setLayout(new MigLayout("insets 0 0 0 0,wrap 2", "[right][grow,fill]", ""));
 
-	@Override
-	public void setItem( Channel item )
-	{
-		super.setItem( item );
-		
-		if( hasItem() )
-		{
-			setControlsEnabled( true );
-			
-			DecodeConfiguration config = getItem().getDecodeConfiguration();
-			
-			if( config instanceof DecodeConfigNBFM )
-			{
-				DecodeConfigNBFM nbfm = (DecodeConfigNBFM)config;
-				setModified( false );
-			}
-			else
-			{
-				setModified( true );
-			}
-		}
-		else
-		{
-			setControlsEnabled( false );
-			setModified( false );
-		}
-	}
+        mComboBandwidth = new JComboBox<>();
+        mComboBandwidth.setModel(new DefaultComboBoxModel<DecodeConfigNBFM.Bandwidth>(
+            DecodeConfigNBFM.Bandwidth.values()));
+        mComboBandwidth.setEnabled(false);
+        mComboBandwidth.addActionListener(new ActionListener()
+        {
+            @Override
+            public void actionPerformed(ActionEvent e)
+            {
+                setModified(true);
+            }
+        });
+
+        add(new JLabel("Bandwidth:"));
+        add(mComboBandwidth);
+    }
+
+    @Override
+    public void validate(Editor<Channel> editor) throws EditorValidationException
+    {
+        //No validation
+    }
+
+    @Override
+    public void save()
+    {
+        if(hasItem() && isModified())
+        {
+            DecodeConfigNBFM nbfm = new DecodeConfigNBFM();
+            nbfm.setBandwidth((DecodeConfigNBFM.Bandwidth)mComboBandwidth.getSelectedItem());
+            getItem().setDecodeConfiguration(nbfm);
+        }
+
+        setModified(false);
+    }
+
+    private void setControlsEnabled(boolean enabled)
+    {
+        mComboBandwidth.setEnabled(enabled);
+    }
+
+    @Override
+    public void setItem(Channel item)
+    {
+        super.setItem(item);
+
+        if(hasItem())
+        {
+            setControlsEnabled(true);
+
+            DecodeConfiguration config = getItem().getDecodeConfiguration();
+
+            if(config instanceof DecodeConfigNBFM)
+            {
+                DecodeConfigNBFM nbfm = (DecodeConfigNBFM)config;
+                mComboBandwidth.setSelectedItem(nbfm.getBandwidth());
+                setModified(false);
+            }
+            else
+            {
+                setModified(true);
+            }
+        }
+        else
+        {
+            setControlsEnabled(false);
+            setModified(false);
+        }
+    }
 }

src/main/java/io/github/dsheirer/module/decode/p25/DecodeConfigP25Phase1.java

@@ -22,6 +22,7 @@ import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
 import io.github.dsheirer.module.decode.DecoderType;
 import io.github.dsheirer.module.decode.config.DecodeConfiguration;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 
 public class DecodeConfigP25Phase1 extends DecodeConfiguration
 {
@@ -104,4 +105,14 @@ public class DecodeConfigP25Phase1 extends DecodeConfiguration
     {
         mTrafficChannelPoolSize = size;
     }
+
+    /**
+     * Source channel specification for this decoder
+     */
+    @JsonIgnore
+    @Override
+    public ChannelSpecification getChannelSpecification()
+    {
+        return new ChannelSpecification(50000.0, 12500, 5750.0, 6500.0);
+    }
 }

src/main/java/io/github/dsheirer/module/decode/p25/Trellis_3_4_Rate.java

@@ -350,9 +350,13 @@ public class Trellis_3_4_Rate
 		public void add( Con con )
 		{
 			Node current = getLastNode();
-			
-			Tribit input = INPUT_FROM_CONSTELLATION_MAP
-					.get( con )[ current.getState().getValue() ];
+
+			Tribit input = null;
+
+			if(current != null)
+			{
+				input = INPUT_FROM_CONSTELLATION_MAP.get( con )[ current.getState().getValue() ];
+			}
 
 			/* A non-null input tribit from the lookup table is valid, otherwise
 			 * create 8 alternate branches from the original path to explore 

src/main/java/io/github/dsheirer/module/decode/passport/DecodeConfigPassport.java

@@ -1,7 +1,6 @@
-/*
- * *********************************************************************************************************************
- * sdrtrunk
- * Copyright (C) 2014-2017 Dennis Sheirer
+/*******************************************************************************
+ * sdr-trunk
+ * Copyright (C) 2014-2018 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
@@ -12,13 +11,15 @@
  *
  * 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 io.github.dsheirer.module.decode.passport;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
 import io.github.dsheirer.module.decode.DecoderType;
 import io.github.dsheirer.module.decode.config.DecodeConfiguration;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 
 public class DecodeConfigPassport extends DecodeConfiguration
 {
@@ -31,4 +32,14 @@ public class DecodeConfigPassport extends DecodeConfiguration
     {
         return DecoderType.PASSPORT;
     }
+
+    /**
+     * Source channel specification for this decoder
+     */
+    @JsonIgnore
+    @Override
+    public ChannelSpecification getChannelSpecification()
+    {
+        return new ChannelSpecification(25000.0, 12500, 6000.0, 7000.0);
+    }
 }

src/main/java/io/github/dsheirer/sample/buffer/ReusableComplexDelayBuffer.java

@@ -0,0 +1,268 @@
+/*******************************************************************************
+ * sdr-trunk
+ * Copyright (C) 2014-2018 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 io.github.dsheirer.sample.buffer;
+
+import io.github.dsheirer.sample.Listener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.LinkedTransferQueue;
+
+/**
+ * Delay buffer/queue for reusable complex buffers with support for pre-loading new buffer listeners (ie channels)
+ * with delayed sample buffers and broadcasting of incoming sample buffers to a list of listeners.
+ *
+ * This class is designed to compensate/account for any delays in processing of a control channel and subsequent
+ * channel grants so that when a new channel is allocated, that channel can be pre-loaded with time delayed sample
+ * buffers that start as close as possible to the channel grant timestamp, in order to avoid cutting off the
+ * beginning of a channel grant transmission.
+ *
+ * New channel listeners are enqueued with a request timestamp and as new buffers arrive, the new channel listeners
+ * are preloaded with delayed buffers from the queue and then added to an internal broadcaster so that they
+ * receive all subsequent buffers as normal.
+ *
+ * This class is designed to be controlled by the sample producer thread for adding new listeners and pre-loading
+ * delayed buffers.  Any listeners that are added to this class are expected to implement a non-blocking receive method
+ * so as not to delay the stream of sample buffers.  Channel listeners are expected to implement buffer queue processing
+ * on another thread.
+ */
+public class ReusableComplexDelayBuffer implements Listener<ReusableComplexBuffer>
+{
+    private final static Logger mLog = LoggerFactory.getLogger(ReusableComplexDelayBuffer.class);
+
+    private ReusableBufferBroadcaster<ReusableComplexBuffer> mBroadcaster = new ReusableBufferBroadcaster<>();
+    private LinkedTransferQueue<ActionRequest> mActionRequestQueue = new LinkedTransferQueue<>();
+    private ActionRequest mActionRequest;
+
+    private ReusableComplexBuffer[] mDelayBuffer;
+    private int mDelayBufferPointer = 0;
+    private long mBufferDuration;
+
+    /**
+     * Creates a new delay buffer with the specified delay length and the buffer sample rate.
+     *
+     * @param size of the delay queue
+     * @param bufferDuration in milliseconds for each complex buffer processed by this instance
+     */
+    public ReusableComplexDelayBuffer(int size, long bufferDuration)
+    {
+        mDelayBuffer = new ReusableComplexBuffer[size];
+        mBufferDuration = bufferDuration;
+    }
+
+    /**
+     * Prepares this instance for disposal by releasing all stored sample buffers.
+     */
+    public void dispose()
+    {
+        clearBuffer();
+    }
+
+    public void clear()
+    {
+        //Submit a clear buffer request to be processed upon the next buffer that arrives
+        mActionRequestQueue.offer(new ActionRequest());
+    }
+
+    /**
+     * Clears any delayed/enqueued sample buffers.
+     */
+    private void clearBuffer()
+    {
+        for(int x = 0; x < mDelayBuffer.length; x++)
+        {
+            if(mDelayBuffer[x] != null)
+            {
+                mDelayBuffer[x].decrementUserCount();
+                mDelayBuffer[x] = null;
+            }
+        }
+
+        mDelayBufferPointer = 0;
+    }
+
+    @Override
+    public synchronized void receive(ReusableComplexBuffer reusableComplexBuffer)
+    {
+        mActionRequest = mActionRequestQueue.poll();
+
+        while(mActionRequest != null)
+        {
+            switch(mActionRequest.getAction())
+            {
+                case ADD_USER:
+                    processNewListener(mActionRequest);
+                    break;
+                case REMOVE_USER:
+                    mBroadcaster.removeListener(mActionRequest.getListener());
+                    break;
+                case CLEAR_BUFFER:
+                    clearBuffer();
+                    break;
+            }
+
+            mActionRequest = mActionRequestQueue.poll();
+        }
+
+        //Increment user count before we hand it to the broadcaster so that we can keep it as a copy for the
+        //delay buffer
+        reusableComplexBuffer.incrementUserCount();
+
+        mBroadcaster.receive(reusableComplexBuffer);
+
+        //Decrement the user count on the oldest buffer before we replace it in the delay queue
+        if(mDelayBuffer[mDelayBufferPointer] != null)
+        {
+            mDelayBuffer[mDelayBufferPointer].decrementUserCount();
+        }
+
+        //Store the new buffer in the delay queue and increment the pointer
+        mDelayBuffer[mDelayBufferPointer++] = reusableComplexBuffer;
+
+        //Wrap the delay buffer pointer as needed
+        if(mDelayBufferPointer >= mDelayBuffer.length)
+        {
+            mDelayBufferPointer = 0;
+        }
+    }
+
+    /**
+     * Indicates if any listeners are registered with this delay buffer
+     */
+    public boolean hasListeners()
+    {
+        return mBroadcaster.hasListeners();
+    }
+
+    /**
+     * Processes any newly added listeners by checking all buffers in the delay queue and pre-loading the
+     * listeners with any buffers that occur on or after the listener's requested start timestamp.
+     */
+    private void processNewListener(ActionRequest listenerToAdd)
+    {
+        ReusableComplexBuffer bufferToEvaluate;
+
+        int pointer = mDelayBufferPointer;
+
+        int preloadedBufferCount = 0;
+
+        for(int x = 0; x < mDelayBuffer.length; x++)
+        {
+            bufferToEvaluate = mDelayBuffer[pointer];
+
+            if(bufferToEvaluate != null &&
+                (bufferToEvaluate.getTimestamp() >= listenerToAdd.getTimestamp() ||
+                    bufferToEvaluate.getTimestamp() + mBufferDuration >= listenerToAdd.getTimestamp()))
+            {
+                bufferToEvaluate.incrementUserCount();
+                listenerToAdd.getListener().receive(bufferToEvaluate);
+                preloadedBufferCount++;
+            }
+
+            pointer++;
+
+            if(pointer >= mDelayBuffer.length)
+            {
+                pointer = 0;
+            }
+        }
+
+        mBroadcaster.addListener(listenerToAdd.getListener());
+    }
+
+    /**
+     * Adds the listener to receive a copy of each buffer.  The listener will be preloaded with delayed buffers
+     * that are at or after the specified timestamp.
+     *
+     * @param listener to add
+     * @param timestamp of the oldest sample buffers to preload to the listener
+     */
+    public void addListener(Listener<ReusableComplexBuffer> listener, long timestamp)
+    {
+        mActionRequestQueue.add(new ActionRequest(listener, timestamp));
+    }
+
+    /**
+     * Removes the listener from receiving sample buffers
+     */
+    public void removeListener(Listener<ReusableComplexBuffer> listener)
+    {
+        mActionRequestQueue.add(new ActionRequest(listener));
+    }
+
+    private enum Action{ADD_USER, REMOVE_USER, CLEAR_BUFFER};
+
+    /**
+     * Actions that must be completed on the incoming sample stream thread.
+     */
+    public class ActionRequest
+    {
+        private Action mAction;
+        private Listener<ReusableComplexBuffer> mListener;
+        private long mTimestamp;
+
+        /**
+         * Creates an add listener request
+         * @param listener to add
+         * @param timestamp for the preloading buffers to the listener from the delay queue
+         */
+        public ActionRequest(Listener<ReusableComplexBuffer> listener, long timestamp)
+        {
+            mAction = Action.ADD_USER;
+            mListener = listener;
+            mTimestamp = timestamp;
+        }
+
+        /**
+         * Creates a remove listener request
+         * @param listener
+         */
+        public ActionRequest(Listener<ReusableComplexBuffer> listener)
+        {
+            mAction = Action.REMOVE_USER;
+            mListener = listener;
+        }
+
+        /**
+         * Creates a clearBuffer buffer request
+         */
+        public ActionRequest()
+        {
+            mAction = Action.CLEAR_BUFFER;
+        }
+
+        public Action getAction()
+        {
+            return mAction;
+        }
+
+        /**
+         * Listener to be added/removed
+         */
+        public Listener<ReusableComplexBuffer> getListener()
+        {
+            return mListener;
+        }
+
+        /**
+         * Requested timestamp for buffers to be preloaded.
+         */
+        public long getTimestamp()
+        {
+            return mTimestamp;
+        }
+    }
+}

src/main/java/io/github/dsheirer/source/SourceEvent.java

@@ -56,20 +56,28 @@ public class SourceEvent
     /**
      * Private constructor.  Use the static constructor methods to create an event.
      */
-    private SourceEvent(Event event, Number value, String eventDescription)
+    private SourceEvent(Event event, Source source, Number value, String eventDescription)
     {
         mEvent = event;
+        mSource = source;
         mValue = value;
         mEventDescription = eventDescription;
     }
 
+    /**
+     * Private constructor.  Use the static constructor methods to create an event.
+     */
+    private SourceEvent(Event event, Number value, String eventDescription)
+    {
+        this(event, null, value, eventDescription);
+    }
+
     /**
      * Private constructor.  Use the static constructor methods to create an event.
      */
     private SourceEvent(Event event, Number value)
     {
-        mEvent = event;
-        mValue = value;
+        this(event, value, null);
     }
 
     /**
@@ -77,8 +85,12 @@ public class SourceEvent
      */
     private SourceEvent(Event event, Source source)
     {
-        mEvent = event;
-        mSource = source;
+        this(event, source, 0);
+    }
+
+    private SourceEvent(Event event, Source source, Number value)
+    {
+        this(event, source, value, null);
     }
 
     /**
@@ -283,11 +295,22 @@ public class SourceEvent
     }
 
     /**
-     * Creates a new start sample stream request event
+     * Creates a new start sample stream request event.  This method uses the current system time in
+     * milliseconds as the requested sample start time.
      */
     public static SourceEvent startSampleStreamRequest(Source source)
     {
-        return new SourceEvent(Event.REQUEST_START_SAMPLE_STREAM, source);
+        return startSampleStreamRequest(source, System.currentTimeMillis());
+    }
+
+    /**
+     * Creates a new start sample stream request event and requests that samples (when available) for the
+     * specified timestamp be pre-loaded into the source.  The timestamp only applies for sources that incorporate
+     * a sample delay buffer.
+     */
+    public static SourceEvent startSampleStreamRequest(Source source, long timestamp)
+    {
+        return new SourceEvent(Event.REQUEST_START_SAMPLE_STREAM, source, timestamp);
     }
 
     /**
@@ -299,7 +322,7 @@ public class SourceEvent
     }
 
     /**
-     * Creates a new stop sample stream request event
+     * Creates a new stop sample stream notification event
      */
     public static SourceEvent stopSampleStreamNotification(Source source)
     {

src/main/java/io/github/dsheirer/source/SourceManager.java

@@ -25,6 +25,7 @@ import io.github.dsheirer.source.mixer.MixerManager;
 import io.github.dsheirer.source.recording.RecordingSourceManager;
 import io.github.dsheirer.source.tuner.TunerManager;
 import io.github.dsheirer.source.tuner.TunerModel;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 
 public class SourceManager
 {
@@ -73,8 +74,7 @@ public class SourceManager
         return mTunerModel;
     }
 
-    public Source getSource(SourceConfiguration config, int bandwidth)
-        throws SourceException
+    public Source getSource(SourceConfiguration config, ChannelSpecification channelSpecification) throws SourceException
     {
         Source retVal = null;
 
@@ -84,10 +84,10 @@ public class SourceManager
                 retVal = mMixerManager.getSource(config);
                 break;
             case TUNER:
-                retVal = mTunerModel.getSource((SourceConfigTuner) config, bandwidth);
+                retVal = mTunerModel.getSource((SourceConfigTuner) config, channelSpecification);
                 break;
             case RECORDING:
-                retVal = mRecordingSourceManager.getSource(config, bandwidth);
+                retVal = mRecordingSourceManager.getSource(config, channelSpecification);
             case NONE:
             default:
                 break;

src/main/java/io/github/dsheirer/source/mixer/ComplexMixer.java

@@ -47,6 +47,14 @@ public class ComplexMixer
         mName = name;
     }
 
+    /**
+     * Audio format used by the underlying mixer reader
+     */
+    public AudioFormat getAudioFormat()
+    {
+        return mMixerReader.getAudioFormat();
+    }
+
     /**
      * Sets the buffer size in bytes per buffer for each read interval.
      * @param bufferSize in bytes

src/main/java/io/github/dsheirer/source/mixer/MixerReader.java

@@ -72,6 +72,14 @@ public class MixerReader<T extends ReusableFloatBuffer> implements Runnable
         this(audioFormat, targetDataLine, abstractSampleAdapter, null);
     }
 
+    /**
+     * Audio format used by this reader
+     */
+    public AudioFormat getAudioFormat()
+    {
+        return mAudioFormat;
+    }
+
     /**
      * Sets the size of buffers to use.  This reader will read from target data line 20 times per second.
      * @param bytesPerBuffer to size for each buffer read.

src/main/java/io/github/dsheirer/source/recording/RecordingSourceManager.java

@@ -1,19 +1,17 @@
 /*******************************************************************************
- *     SDR Trunk 
- *     Copyright (C) 2014 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/>
+ * sdr-trunk
+ * Copyright (C) 2014-2018 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 io.github.dsheirer.source.recording;
 
@@ -22,6 +20,7 @@ import io.github.dsheirer.source.Source;
 import io.github.dsheirer.source.SourceException;
 import io.github.dsheirer.source.config.SourceConfigRecording;
 import io.github.dsheirer.source.config.SourceConfiguration;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 import io.github.dsheirer.source.tuner.channel.TunerChannel;
 import io.github.dsheirer.source.tuner.channel.TunerChannelSource;
 import org.slf4j.Logger;
@@ -33,64 +32,64 @@ import java.util.List;
 
 public class RecordingSourceManager
 {
-	private final static Logger mLog = LoggerFactory.getLogger( RecordingSourceManager.class );
+    private final static Logger mLog = LoggerFactory.getLogger(RecordingSourceManager.class);
 
-	private ArrayList<Recording> mRecordings = new ArrayList<Recording>();
+    private ArrayList<Recording> mRecordings = new ArrayList<Recording>();
 
-	private SettingsManager mSettingsManager;
+    private SettingsManager mSettingsManager;
 
-    public RecordingSourceManager( SettingsManager settingsManager )
-	{
-    	mSettingsManager = settingsManager;
-    	loadRecordings();
-	}
+    public RecordingSourceManager(SettingsManager settingsManager)
+    {
+        mSettingsManager = settingsManager;
+        loadRecordings();
+    }
 
     /**
      * Iterates current recordings to get a tuner channel source for the frequency
      * specified in the channel config's source config object
      */
-    public Source getSource( SourceConfiguration config, int bandwidth )
-    					throws SourceException
+    public Source getSource(SourceConfiguration config, ChannelSpecification channelSpecification)
+        throws SourceException
     {
-    	TunerChannelSource retVal = null;
+        TunerChannelSource retVal = null;
 
-    	if( config instanceof SourceConfigRecording )
-    	{
-    		SourceConfigRecording configRecording = (SourceConfigRecording)config;
-    		
-        	TunerChannel tunerChannel = configRecording.getTunerChannel();
-        	
-        	tunerChannel.setBandwidth( bandwidth );
+        if(config instanceof SourceConfigRecording)
+        {
+            SourceConfigRecording configRecording = (SourceConfigRecording)config;
 
-    		Recording recording = getRecordingFromAlias( 
-    				configRecording.getRecordingAlias() );
-    		
-    		if( recording != null )
-    		{
-    			retVal = recording.getChannel( tunerChannel );
-    		}
-    		else
-    		{
-    			throw new SourceException( "Recording with alias name [" +
-					configRecording.getRecordingAlias() + "] is not currently available" );
-    		}
-    	}
-    	
-    	return retVal;
+            TunerChannel tunerChannel = configRecording.getTunerChannel();
+
+            tunerChannel.setBandwidth(channelSpecification.getBandwidth());
+
+            Recording recording = getRecordingFromAlias(
+                configRecording.getRecordingAlias());
+
+            if(recording != null)
+            {
+                retVal = recording.getChannel(tunerChannel);
+            }
+            else
+            {
+                throw new SourceException("Recording with alias name [" +
+                    configRecording.getRecordingAlias() + "] is not currently available");
+            }
+        }
+
+        return retVal;
     }
-    
-    public Recording getRecordingFromAlias( String alias )
+
+    public Recording getRecordingFromAlias(String alias)
     {
-    	for( Recording recording: mRecordings )
-    	{
-    		if( recording.getRecordingConfiguration()
-    				.getAlias().contentEquals( alias ) )
-    		{
-    			return recording;
-    		}
-    	}
-    	
-    	return null;
+        for(Recording recording : mRecordings)
+        {
+            if(recording.getRecordingConfiguration()
+                .getAlias().contentEquals(alias))
+            {
+                return recording;
+            }
+        }
+
+        return null;
     }
 
     /**
@@ -98,47 +97,47 @@ public class RecordingSourceManager
      */
     public List<Recording> getRecordings()
     {
-    	Collections.sort( mRecordings );
-    	
-    	return mRecordings;
-    }
-    
-    public void addRecording( Recording recording )
-    {
-    	mRecordings.add( recording );
-    }
-    
-    public Recording addRecording( RecordingConfiguration config )
-    {
-    	Recording recording = new Recording( mSettingsManager, config );
+        Collections.sort(mRecordings);
 
-    	mRecordings.add( recording );
-    	
-    	return recording;
+        return mRecordings;
     }
-    
-    public void removeRecording( Recording recording )
+
+    public void addRecording(Recording recording)
     {
-    	/* Remove the config from the settings manager */
-    	mSettingsManager.removeRecordingConfiguration( 
-    			recording.getRecordingConfiguration() );
-    	
-    	mRecordings.remove( recording );
+        mRecordings.add(recording);
+    }
+
+    public Recording addRecording(RecordingConfiguration config)
+    {
+        Recording recording = new Recording(mSettingsManager, config);
+
+        mRecordings.add(recording);
+
+        return recording;
+    }
+
+    public void removeRecording(Recording recording)
+    {
+        /* Remove the config from the settings manager */
+        mSettingsManager.removeRecordingConfiguration(
+            recording.getRecordingConfiguration());
+
+        mRecordings.remove(recording);
     }
 
     private void loadRecordings()
     {
-		List<RecordingConfiguration> recordingConfigurations = 
-				mSettingsManager.getRecordingConfigurations();
+        List<RecordingConfiguration> recordingConfigurations =
+            mSettingsManager.getRecordingConfigurations();
 
-		mLog.info( "RecordingSourceManager - discovered [" + 
-		recordingConfigurations.size() + "] recording configurations" );
-		
-		for( RecordingConfiguration config: recordingConfigurations )
-		{
-			Recording recording = new Recording( mSettingsManager, config );
-			
-			mRecordings.add( recording );
-		}
-	}
+        mLog.info("RecordingSourceManager - discovered [" +
+            recordingConfigurations.size() + "] recording configurations");
+
+        for(RecordingConfiguration config : recordingConfigurations)
+        {
+            Recording recording = new Recording(mSettingsManager, config);
+
+            mRecordings.add(recording);
+        }
+    }
 }

src/main/java/io/github/dsheirer/source/tuner/Tuner.java

@@ -21,7 +21,7 @@ import io.github.dsheirer.source.ISourceEventProcessor;
 import io.github.dsheirer.source.SourceEvent;
 import io.github.dsheirer.source.tuner.TunerEvent.Event;
 import io.github.dsheirer.source.tuner.manager.ChannelSourceManager;
-import io.github.dsheirer.source.tuner.manager.HeterodyneChannelSourceManager;
+import io.github.dsheirer.source.tuner.manager.PolyphaseChannelSourceManager;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -51,8 +51,8 @@ public abstract class Tuner implements ISourceEventProcessor
         //Register to receive frequency and sample rate change notifications
         mTunerController.addListener(this::process);
 
-//        mChannelSourceManager = new PolyphaseChannelSourceManager(mTunerController);
-        mChannelSourceManager = new HeterodyneChannelSourceManager(mTunerController);
+        mChannelSourceManager = new PolyphaseChannelSourceManager(mTunerController);
+//        mChannelSourceManager = new HeterodyneChannelSourceManager(mTunerController);
 
         //Register to receive channel count change notifications
         mChannelSourceManager.addSourceEventListener(this::process);

src/main/java/io/github/dsheirer/source/tuner/TunerController.java

@@ -26,12 +26,15 @@ import io.github.dsheirer.source.ISourceEventProcessor;
 import io.github.dsheirer.source.SourceEvent;
 import io.github.dsheirer.source.SourceEventListenerToProcessorAdapter;
 import io.github.dsheirer.source.SourceException;
+import io.github.dsheirer.source.tuner.channel.TunerChannel;
 import io.github.dsheirer.source.tuner.configuration.TunerConfiguration;
 import io.github.dsheirer.source.tuner.frequency.FrequencyController;
 import io.github.dsheirer.source.tuner.frequency.FrequencyController.Tunable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.SortedSet;
+
 public abstract class TunerController implements Tunable, ISourceEventProcessor, ISourceEventListener,
     IReusableComplexBufferProvider, Listener<ReusableComplexBuffer>
 {
@@ -67,6 +70,21 @@ public abstract class TunerController implements Tunable, ISourceEventProcessor,
      */
     public abstract void dispose();
 
+    /**
+     * Number of samples contained in each complex buffer provided by this tuner.
+     *
+     * @return number of complex sample in each buffer.
+     */
+    public abstract int getBufferSampleCount();
+
+    /**
+     * Duration in milliseconds for each sample buffer provided by this tuner
+     */
+    public long getBufferDuration()
+    {
+        return (long)(1000.0 / (getSampleRate() / (double)getBufferSampleCount()));
+    }
+
     /**
      * Implements the ISourceEventListener interface to receive requests from sample consumers
      */
@@ -346,4 +364,85 @@ public abstract class TunerController implements Tunable, ISourceEventProcessor,
     {
         broadcast(complexBuffer);
     }
+
+    /**
+     * Indicates if the current center frequency and bandwidth is correct to source the tuner channel
+     *
+     * @param tunerChannel to test
+     * @return true if the current center frequency and bandwidth is correct for the channel
+     */
+    public boolean isTunedFor(TunerChannel tunerChannel)
+    {
+        try
+        {
+            if(tunerChannel.getMinFrequency() < getMinTunedFrequency())
+            {
+                return false;
+            }
+
+            if(tunerChannel.getMaxFrequency() > getMaxTunedFrequency())
+            {
+                return false;
+            }
+
+            if(hasMiddleUnusableBandwidth())
+            {
+                long minAvoid = getFrequency() - getMiddleUnusableHalfBandwidth();
+                long maxAvoid = getFrequency() + getMiddleUnusableHalfBandwidth();
+
+                if(tunerChannel.overlaps(minAvoid, maxAvoid))
+                {
+                    return false;
+                }
+            }
+        }
+        catch(SourceException se)
+        {
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Indicates if the current center frequency and bandwidth is correct to source the tuner channel set
+     *
+     * @param tunerChannels to test
+     * @return true if the current center frequency and bandwidth is correct for the channel set
+     */
+    public boolean isTunedFor(SortedSet<TunerChannel> tunerChannels)
+    {
+        try
+        {
+            if(tunerChannels.first().getMinFrequency() < getMinTunedFrequency())
+            {
+                return false;
+            }
+
+            if(tunerChannels.last().getMaxFrequency() > getMaxTunedFrequency())
+            {
+                return false;
+            }
+
+            if(hasMiddleUnusableBandwidth())
+            {
+                long minAvoid = getFrequency() - getMiddleUnusableHalfBandwidth();
+                long maxAvoid = getFrequency() + getMiddleUnusableHalfBandwidth();
+
+                for(TunerChannel tunerChannel: tunerChannels)
+                {
+                    if(tunerChannel.overlaps(minAvoid, maxAvoid))
+                    {
+                        return false;
+                    }
+                }
+            }
+        }
+        catch(SourceException se)
+        {
+            return false;
+        }
+
+        return true;
+    }
 }

src/main/java/io/github/dsheirer/source/tuner/TunerManager.java

@@ -71,6 +71,10 @@ public class TunerManager
      */
     public void dispose()
     {
+        mLog.info("Shutting down LibUsb timeout processor ...");
+
+        LIBUSB_TRANSFER_PROCESSOR.shutdown();
+
         mLog.info("Shutting down LibUsb ...");
         try
         {

src/main/java/io/github/dsheirer/source/tuner/TunerModel.java

@@ -21,11 +21,13 @@ import io.github.dsheirer.source.Source;
 import io.github.dsheirer.source.SourceException;
 import io.github.dsheirer.source.config.SourceConfigTuner;
 import io.github.dsheirer.source.tuner.TunerEvent.Event;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 import io.github.dsheirer.source.tuner.channel.TunerChannel;
 import io.github.dsheirer.source.tuner.channel.TunerChannelSource;
 import io.github.dsheirer.source.tuner.configuration.TunerConfiguration;
 import io.github.dsheirer.source.tuner.configuration.TunerConfigurationModel;
 import io.github.dsheirer.spectrum.SpectralDisplayPanel;
+import io.github.dsheirer.util.ThreadPool;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -34,6 +36,7 @@ import java.text.DecimalFormat;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.concurrent.TimeUnit;
 
 public class TunerModel extends AbstractTableModel implements Listener<TunerEvent>
 {
@@ -201,7 +204,17 @@ public class TunerModel extends AbstractTableModel implements Listener<TunerEven
 
         if(enabled && mTuners.size() > 0)
         {
-            broadcast(new TunerEvent(mTuners.get(0), Event.REQUEST_MAIN_SPECTRAL_DISPLAY));
+            //Hack: the airspy tuner would lockup aperiodically and refuse to produce
+            //transfer buffers ... delaying registering for buffers for 500 ms seems
+            //to allow the airspy to stabilize before we start asking for samples.
+            ThreadPool.SCHEDULED.schedule(new Runnable()
+            {
+                @Override
+                public void run()
+                {
+                    broadcast(new TunerEvent(mTuners.get(0), Event.REQUEST_MAIN_SPECTRAL_DISPLAY));
+                }
+            }, 500, TimeUnit.MILLISECONDS);
         }
         else
         {
@@ -327,13 +340,13 @@ public class TunerModel extends AbstractTableModel implements Listener<TunerEven
      *
      * Returns null if no tuner can source the channel
      */
-    public Source getSource(SourceConfigTuner config, int bandwidth)
+    public Source getSource(SourceConfigTuner config, ChannelSpecification channelSpecification)
     {
         TunerChannelSource retVal = null;
 
         TunerChannel tunerChannel = config.getTunerChannel();
 
-        tunerChannel.setBandwidth(bandwidth);
+        tunerChannel.setBandwidth(channelSpecification.getBandwidth());
 
         Iterator<Tuner> it = mTuners.iterator();
 
@@ -347,7 +360,7 @@ public class TunerModel extends AbstractTableModel implements Listener<TunerEven
             {
                 try
                 {
-                    retVal = tuner.getChannelSourceManager().getSource(tunerChannel);
+                    retVal = tuner.getChannelSourceManager().getSource(tunerChannel, channelSpecification);
 
                     if(retVal != null)
                     {
@@ -370,7 +383,7 @@ public class TunerModel extends AbstractTableModel implements Listener<TunerEven
 
             try
             {
-                retVal = tuner.getChannelSourceManager().getSource(tunerChannel);
+                retVal = tuner.getChannelSourceManager().getSource(tunerChannel, channelSpecification);
             }
             catch(Exception e)
             {

src/main/java/io/github/dsheirer/source/tuner/airspy/AirspyTunerController.java

@@ -107,6 +107,13 @@ public class AirspyTunerController extends USBTunerController
         mDevice = device;
     }
 
+    @Override
+    public int getBufferSampleCount()
+    {
+        //Each airspy complex sample is 4 bytes, so sample count is buffer size / 4
+        return USB_TRANSFER_BUFFER_SIZE / 4;
+    }
+
     public void init() throws SourceException
     {
         mDeviceHandle = new DeviceHandle();

src/main/java/io/github/dsheirer/source/tuner/channel/CICTunerChannelSource.java

@@ -19,6 +19,7 @@ import io.github.dsheirer.dsp.filter.cic.ComplexPrimeCICDecimate;
 import io.github.dsheirer.dsp.filter.design.FilterDesignException;
 import io.github.dsheirer.dsp.mixer.IOscillator;
 import io.github.dsheirer.dsp.mixer.LowPhaseNoiseOscillator;
+import io.github.dsheirer.sample.IOverflowListener;
 import io.github.dsheirer.sample.Listener;
 import io.github.dsheirer.sample.buffer.OverflowableReusableBufferTransferQueue;
 import io.github.dsheirer.sample.buffer.ReusableComplexBuffer;
@@ -44,17 +45,10 @@ public class CICTunerChannelSource extends TunerChannelSource implements Listene
     //Threshold for resetting buffer overflow condition
     private static final int BUFFER_OVERFLOW_RESET_THRESHOLD = 100;
 
-    //Pass band cutoff frequency for the complex channel - target = 12.5 kHz channel
-    private static final int CHANNEL_PASS_FREQUENCY = 6000;
-
-    //Stop band frequency for the complex channel
-    private static final int CHANNEL_STOP_FREQUENCY = 6700;
-
     private OverflowableReusableBufferTransferQueue<ReusableComplexBuffer> mBuffer;
     private ReusableComplexBufferQueue mReusableComplexBufferQueue = new ReusableComplexBufferQueue("CICTunerChannelSource");
     private IOscillator mFrequencyCorrectionMixer;
     private ComplexPrimeCICDecimate mDecimationFilter;
-    private Listener<ReusableComplexBuffer> mListener;
     private List<ReusableComplexBuffer> mSampleBuffers = new ArrayList<>();
     private double mChannelSampleRate;
     private long mChannelFrequencyCorrection = 0;
@@ -66,18 +60,22 @@ public class CICTunerChannelSource extends TunerChannelSource implements Listene
      * @param producerSourceEventListener to receive sample stream start/stop requests
      * @param tunerChannel that details the desired channel frequency and bandwidth
      * @param sampleRate of the incoming sample stream
-     * @param decimation to use in the CIC decimation filter.
+     * @param channelSpecification for the requested channel.
      * @throws FilterDesignException if a final cleanup filter cannot be designed using the remez filter
      *                               designer and the filter parameters.
      */
     public CICTunerChannelSource(Listener<SourceEvent> producerSourceEventListener, TunerChannel tunerChannel,
-                                 double sampleRate, int decimation) throws FilterDesignException
+                 double sampleRate, ChannelSpecification channelSpecification) throws FilterDesignException
     {
         super(producerSourceEventListener, tunerChannel);
 
-        mDecimationFilter = new ComplexPrimeCICDecimate(sampleRate, decimation, CHANNEL_PASS_FREQUENCY, CHANNEL_STOP_FREQUENCY);
+        int decimation = (int)(sampleRate / channelSpecification.getMinimumSampleRate());
+
+        mDecimationFilter = new ComplexPrimeCICDecimate(sampleRate, decimation, channelSpecification.getPassFrequency(),
+            channelSpecification.getStopFrequency());
 
         mBuffer = new OverflowableReusableBufferTransferQueue<>(BUFFER_MAX_CAPACITY, BUFFER_OVERFLOW_RESET_THRESHOLD);
+
         //Setup the frequency mixer to the current source frequency
         mChannelSampleRate = sampleRate / (double)decimation;
         mTunerFrequency = tunerChannel.getFrequency();
@@ -86,6 +84,18 @@ public class CICTunerChannelSource extends TunerChannelSource implements Listene
         mFrequencyCorrectionMixer = new LowPhaseNoiseOscillator(frequencyOffset, sampleRate);
     }
 
+    /**
+     * Registers an overflow listener to be notified in the internal buffer is in an
+     * overflow state.
+     *
+     * @param listener to receiver updates to the source overflow state
+     */
+    @Override
+    public void setOverflowListener(IOverflowListener listener)
+    {
+        mBuffer.setOverflowListener(listener);
+    }
+
     @Override
     public void dispose()
     {

src/main/java/io/github/dsheirer/source/tuner/channel/ChannelSpecification.java

@@ -0,0 +1,74 @@
+/*******************************************************************************
+ * sdr-trunk
+ * Copyright (C) 2014-2018 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 io.github.dsheirer.source.tuner.channel;
+
+/**
+ * Channel source specification
+ */
+public class ChannelSpecification
+{
+    private double mMinimumSampleRate;
+    private int mBandwidth;
+    private double mPassFrequency;
+    private double mStopFrequency;
+
+    /**
+     * Constructs a channel specification instance.
+     * @param minimumSampleRate requested for the channel
+     * @param bandwidth
+     * @param passFrequency for the pass band of the channel
+     * @param stopFrequency for the stop band of teh channel
+     */
+    public ChannelSpecification(double minimumSampleRate, int bandwidth, double passFrequency, double stopFrequency)
+    {
+        mMinimumSampleRate = minimumSampleRate;
+        mBandwidth = bandwidth;
+        mPassFrequency = passFrequency;
+        mStopFrequency = stopFrequency;
+    }
+
+    /**
+     * Minimum requested sample rate for the channel
+     */
+    public double getMinimumSampleRate()
+    {
+        return mMinimumSampleRate;
+    }
+
+    /**
+     * Bandwidth of the channel in Hertz
+     */
+    public int getBandwidth()
+    {
+        return mBandwidth;
+    }
+
+    /**
+     * Pass band frequency for filtering the channel
+     */
+    public double getPassFrequency()
+    {
+        return mPassFrequency;
+    }
+
+    /**
+     * Stop band frequency for filtering the channel
+     */
+    public double getStopFrequency()
+    {
+        return mStopFrequency;
+    }
+}

src/main/java/io/github/dsheirer/source/tuner/channel/TunerChannelSource.java

@@ -286,8 +286,26 @@ public abstract class TunerChannelSource extends ComplexSource implements ISourc
         {
             if(!mStopped)
             {
-                getHeartbeatManager().broadcast();
-                processSamples();
+                try
+                {
+                    getHeartbeatManager().broadcast();
+                }
+                catch(Throwable t)
+                {
+                    mLog.error("Error while sending heartbeat", t);
+                }
+            }
+
+            if(!mStopped)
+            {
+                try
+                {
+                    processSamples();
+                }
+                catch(Throwable t)
+                {
+                    mLog.error("Error while processing samples", t);
+                }
             }
 
             if(mStopped)
@@ -300,7 +318,15 @@ public abstract class TunerChannelSource extends ComplexSource implements ISourc
 
                 mScheduledFuture = null;
 
-                performDisposal();
+                try
+                {
+                    getHeartbeatManager().broadcast();
+                    performDisposal();
+                }
+                catch(Throwable t)
+                {
+                    mLog.error("Error during final shutdown processing of samples", t);
+                }
             }
         }
     }

src/main/java/io/github/dsheirer/source/tuner/fcd/FCDTunerController.java

@@ -90,11 +90,17 @@ public abstract class FCDTunerController extends TunerController
         mComplexMixer = new ComplexMixer( mixerTDL.getTargetDataLine(), audioFormat, tunerName,
             new ComplexShortAdapter(mixerTDL.getMixerTunerType().getDisplayString()));
 
-        mComplexMixer.setBufferSize(audioFormat.getFrameSize() * (int)(audioFormat.getSampleRate() * 0.1));
+        mComplexMixer.setBufferSize(audioFormat.getFrameSize() * getBufferSampleCount());
 
         mComplexMixer.setBufferListener(mReusableBufferBroadcaster);
     }
 
+    @Override
+    public int getBufferSampleCount()
+    {
+        return (int)(mComplexMixer.getAudioFormat().getSampleRate() * 0.1);
+    }
+
     /**
      * Overrides the super class functionality to auto-start the complex mixer and provide samples to listeners
      */

src/main/java/io/github/dsheirer/source/tuner/hackrf/HackRFTunerController.java

@@ -109,6 +109,12 @@ public class HackRFTunerController extends USBTunerController
         mDeviceDescriptor = descriptor;
     }
 
+    @Override
+    public int getBufferSampleCount()
+    {
+        return USB_TRANSFER_BUFFER_SIZE / 2;
+    }
+
     public void init() throws SourceException
     {
         mDeviceHandle = new DeviceHandle();

src/main/java/io/github/dsheirer/source/tuner/manager/CenterFrequencyCalculator.java

@@ -54,48 +54,57 @@ public class CenterFrequencyCalculator
             //Start by placing the highest frequency channel at the high end of the spectrum
             candidateFrequency = maxChannelFrequency - (tunerController.getUsableBandwidth() / 2);
 
-            //Iterate the channels and make sure that none of them overlap the center DC spike buffer, if one exists
-            if(tunerController.getMiddleUnusableHalfBandwidth() > 0)
+            if(maxChannelFrequency - minChannelFrequency <= tunerController.getUsableHalfBandwidth())
             {
-                boolean processingRequired = true;
-
-                while(isValidCandidateFrequency && processingRequired)
+                candidateFrequency = minChannelFrequency - tunerController.getMiddleUnusableHalfBandwidth();
+                isValidCandidateFrequency = true;
+            }
+            else
+            {
+                //Iterate the channels and make sure that none of them overlap the center DC spike buffer, if one exists
+                if(tunerController.getMiddleUnusableHalfBandwidth() > 0)
                 {
-                    processingRequired = false;
+                    boolean processingRequired = true;
 
-                    long minAvoid = candidateFrequency - tunerController.getMiddleUnusableHalfBandwidth();
-                    long maxAvoid = candidateFrequency + tunerController.getMiddleUnusableHalfBandwidth();
-
-                    //If any of the center channel(s) overlap the central DC spike avoid area, we'll iteratively
-                    //increase the tuned frequency causing the set of channels to move left in the tuned bandwidth until
-                    //we either find a good center tune frequency, or we walk the lowest frequency channel out of the
-                    //minimum tuned range, in which case we'll throw an exception indicating we don't have a solution.
-                    for(TunerChannel channel : channels)
+                    while(isValidCandidateFrequency && processingRequired)
                     {
-                        if(channel.overlaps(minAvoid, maxAvoid))
+                        processingRequired = false;
+
+                        long minAvoid = candidateFrequency - tunerController.getMiddleUnusableHalfBandwidth();
+                        long maxAvoid = candidateFrequency + tunerController.getMiddleUnusableHalfBandwidth();
+
+                        //If any of the center channel(s) overlap the central DC spike avoid area, we'll iteratively
+                        //increase the tuned frequency causing the set of channels to move left in the tuned bandwidth until
+                        //we either find a good center tune frequency, or we walk the lowest frequency channel out of the
+                        //minimum tuned range, in which case we'll throw an exception indicating we don't have a solution.
+                        for(TunerChannel channel : channels)
                         {
-                            //Calculate a tuned frequency adjustment that places this overlapping channel just to the
-                            //left of the central DC spike avoid zone
-                            long adjustment = channel.getMaxFrequency() - minAvoid + 1;
-
-                            //If the candidate frequency doesn't push the lowest channel out of bounds, make adjustment
-                            if(candidateFrequency + adjustment - (tunerController.getUsableBandwidth() / 2) <= minChannelFrequency)
+                            if(channel.overlaps(minAvoid, maxAvoid))
                             {
-                                candidateFrequency += adjustment;
-                                processingRequired = true;
-                            }
-                            //Otherwise, punt and indicate that we can't find a center frequency or add the channel
-                            else
-                            {
-                                isValidCandidateFrequency = false;
-                            }
+                                //Calculate a tuned frequency adjustment that places this overlapping channel just to the
+                                //left of the central DC spike avoid zone
+                                long adjustment = channel.getMaxFrequency() - minAvoid + 1;
 
-                            //break out of the for/each loop, so that we can start over again with all of the channels
-                            break;
+                                //If the candidate frequency doesn't push the lowest channel out of bounds, make adjustment
+                                if(candidateFrequency + adjustment - (tunerController.getUsableBandwidth() / 2) <= minChannelFrequency)
+                                {
+                                    candidateFrequency += adjustment;
+                                    processingRequired = true;
+                                }
+                                //Otherwise, punt and indicate that we can't find a center frequency or add the channel
+                                else
+                                {
+                                    isValidCandidateFrequency = false;
+                                }
+
+                                //break out of the for/each loop, so that we can start over again with all of the channels
+                                break;
+                            }
                         }
                     }
                 }
             }
+
         }
 
         if(isValidCandidateFrequency)

src/main/java/io/github/dsheirer/source/tuner/manager/ChannelSourceManager.java

@@ -19,6 +19,7 @@ import io.github.dsheirer.sample.Broadcaster;
 import io.github.dsheirer.sample.Listener;
 import io.github.dsheirer.source.ISourceEventProcessor;
 import io.github.dsheirer.source.SourceEvent;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 import io.github.dsheirer.source.tuner.channel.TunerChannel;
 import io.github.dsheirer.source.tuner.channel.TunerChannelSource;
 
@@ -50,9 +51,10 @@ public abstract class ChannelSourceManager implements ISourceEventProcessor
      * resources allocated for the tuner channel source.
      *
      * @param tunerChannel for requested source
+     * @param channelSpecification for the requested channel
      * @return tuner channel source or null
      */
-    public abstract TunerChannelSource getSource(TunerChannel tunerChannel);
+    public abstract TunerChannelSource getSource(TunerChannel tunerChannel, ChannelSpecification channelSpecification);
 
     /**
      * Adds a listener to receive source events

src/main/java/io/github/dsheirer/source/tuner/manager/HeterodyneChannelSourceManager.java

@@ -17,10 +17,12 @@ package io.github.dsheirer.source.tuner.manager;
 
 import io.github.dsheirer.dsp.filter.design.FilterDesignException;
 import io.github.dsheirer.sample.Listener;
+import io.github.dsheirer.sample.buffer.ReusableComplexDelayBuffer;
 import io.github.dsheirer.source.SourceEvent;
 import io.github.dsheirer.source.SourceException;
 import io.github.dsheirer.source.tuner.TunerController;
 import io.github.dsheirer.source.tuner.channel.CICTunerChannelSource;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 import io.github.dsheirer.source.tuner.channel.TunerChannel;
 import io.github.dsheirer.source.tuner.channel.TunerChannelSource;
 import org.slf4j.Logger;
@@ -38,12 +40,13 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
 {
     private final static Logger mLog = LoggerFactory.getLogger(HeterodyneChannelSourceManager.class);
 
-    private final static int OBJECTIVE_CHANNEL_SAMPLE_RATE = 30000;
+    private final static int DELAY_BUFFER_DURATION_MILLISECONDS = 2000;
 
     private List<CICTunerChannelSource> mChannelSources = new CopyOnWriteArrayList<>();
     private SortedSet<TunerChannel> mTunerChannels = new TreeSet<>();
     private TunerController mTunerController;
     private ChannelSourceEventProcessor mChannelSourceEventProcessor = new ChannelSourceEventProcessor();
+    private ReusableComplexDelayBuffer mSampleDelayBuffer;
 
     public HeterodyneChannelSourceManager(TunerController tunerController)
     {
@@ -64,17 +67,15 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
     }
 
     @Override
-    public TunerChannelSource getSource(TunerChannel tunerChannel)
+    public TunerChannelSource getSource(TunerChannel tunerChannel, ChannelSpecification channelSpecification)
     {
         if(CenterFrequencyCalculator.canTune(tunerChannel, mTunerController, mTunerChannels))
         {
-            int decimation = mTunerController.getBandwidth() / OBJECTIVE_CHANNEL_SAMPLE_RATE;
-
             try
             {
                 //Attempt to create the channel source first, in case we get a filter design exception
                 CICTunerChannelSource tunerChannelSource = new CICTunerChannelSource(mChannelSourceEventProcessor,
-                    tunerChannel, mTunerController.getSampleRate(), decimation);
+                    tunerChannel, mTunerController.getSampleRate(), channelSpecification);
 
                 //Add to the list of channel sources so that it will receive the tuner frequency change
                 mChannelSources.add(tunerChannelSource);
@@ -107,23 +108,26 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
      */
     private void updateTunerFrequency()
     {
-        long centerFrequency = CenterFrequencyCalculator.getCenterFrequency(mTunerController, getTunerChannels());
-
-        if(centerFrequency == CenterFrequencyCalculator.INVALID_FREQUENCY)
+        if(!mTunerController.isTunedFor(getTunerChannels()))
         {
-            mLog.error("Couldn't calculate center frequency for tuner and tuner channels");
-            return;
-        }
+            long centerFrequency = CenterFrequencyCalculator.getCenterFrequency(mTunerController, getTunerChannels());
 
-        if(centerFrequency != mTunerController.getFrequency())
-        {
-            try
+            if(centerFrequency == CenterFrequencyCalculator.INVALID_FREQUENCY)
             {
-                mTunerController.setFrequency(centerFrequency);
+                mLog.error("Couldn't calculate center frequency for tuner and tuner channels");
+                return;
             }
-            catch(SourceException se)
+
+            if(centerFrequency != mTunerController.getFrequency())
             {
-                mLog.error("Couldn't update tuner center frequency to " + centerFrequency, se);
+                try
+                {
+                    mTunerController.setFrequency(centerFrequency);
+                }
+                catch(SourceException se)
+                {
+                    mLog.error("Couldn't update tuner center frequency to " + centerFrequency, se);
+                }
             }
         }
     }
@@ -136,6 +140,12 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
             case NOTIFICATION_FREQUENCY_CHANGE:
                 //Tuner center frequency has changed - update channels
                 updateTunerFrequency(tunerSourceEvent.getValue().longValue());
+
+                //Clear the delay buffer since any delayed samples will be centered on the previous frequency
+                if(mSampleDelayBuffer != null)
+                {
+                    mSampleDelayBuffer.clear();
+                }
                 break;
             case NOTIFICATION_FREQUENCY_CORRECTION_CHANGE:
                 //The tuner is self-correcting for PPM error - relay to channels
@@ -156,7 +166,7 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
      */
     private void broadcastToChannels(SourceEvent sourceEvent)
     {
-        for(CICTunerChannelSource channelSource: mChannelSources)
+        for(CICTunerChannelSource channelSource : mChannelSources)
         {
             try
             {
@@ -182,6 +192,39 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
         }
     }
 
+    /**
+     * Creates a complex sample delay buffer and registers it with the tuner controller to start the flow
+     * of complex sample buffers from the tuner.
+     */
+    private void startDelayBuffer()
+    {
+        if(mSampleDelayBuffer == null)
+        {
+            int delayBufferSize = (int)(DELAY_BUFFER_DURATION_MILLISECONDS / mTunerController.getBufferDuration());
+            mSampleDelayBuffer = new ReusableComplexDelayBuffer(delayBufferSize, mTunerController.getBufferDuration());
+
+            mLog.debug("Created/registered complex sample delay buffer of size [" + delayBufferSize +
+                "] buffers and delay duration [" + DELAY_BUFFER_DURATION_MILLISECONDS +
+                "ms] for tuner controller [" + mTunerController.getClass().getName() +
+                "] with buffer duration [" + mTunerController.getBufferDuration() + "]");
+
+            mTunerController.addBufferListener(mSampleDelayBuffer);
+        }
+    }
+
+    /**
+     * Deregisters the complex sample delay buffer and disposes of any queued reusable buffers.
+     */
+    private void stopDelayBuffer()
+    {
+        if(mSampleDelayBuffer != null && !mSampleDelayBuffer.hasListeners())
+        {
+            mTunerController.removeBufferListener(mSampleDelayBuffer);
+            mSampleDelayBuffer.dispose();
+            mSampleDelayBuffer = null;
+        }
+    }
+
     /**
      * Processes channel source events
      */
@@ -195,13 +238,20 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
                 case REQUEST_START_SAMPLE_STREAM:
                     if(sourceEvent.getSource() instanceof CICTunerChannelSource)
                     {
-                        mTunerController.addBufferListener((CICTunerChannelSource)sourceEvent.getSource());
+                        startDelayBuffer();
+
+                        //The start sample stream request contains a start timestamp and the delay buffer
+                        //will preload the channel with delayed sample buffers that either contain the
+                        //timestamp or occur later/newer than the timestamp.
+                        mSampleDelayBuffer.addListener((CICTunerChannelSource)sourceEvent.getSource(),
+                            sourceEvent.getValue().longValue());
                     }
                     break;
                 case REQUEST_STOP_SAMPLE_STREAM:
                     if(sourceEvent.getSource() instanceof CICTunerChannelSource)
                     {
-                        mTunerController.removeBufferListener((CICTunerChannelSource)sourceEvent.getSource());
+                        mSampleDelayBuffer.removeListener((CICTunerChannelSource)sourceEvent.getSource());
+                        stopDelayBuffer();
                     }
                     break;
                 case REQUEST_SOURCE_DISPOSE:

src/main/java/io/github/dsheirer/source/tuner/manager/PolyphaseChannelSourceManager.java

@@ -19,6 +19,7 @@ import io.github.dsheirer.dsp.filter.channelizer.PolyphaseChannelManager;
 import io.github.dsheirer.source.SourceEvent;
 import io.github.dsheirer.source.SourceException;
 import io.github.dsheirer.source.tuner.TunerController;
+import io.github.dsheirer.source.tuner.channel.ChannelSpecification;
 import io.github.dsheirer.source.tuner.channel.TunerChannel;
 import io.github.dsheirer.source.tuner.channel.TunerChannelSource;
 import org.slf4j.Logger;
@@ -390,7 +391,7 @@ public class PolyphaseChannelSourceManager extends ChannelSourceManager
      * @return allocated DDC tuner channel source, or null if the channel cannot be provided by this source manager
      */
     @Override
-    public TunerChannelSource getSource(TunerChannel tunerChannel)
+    public TunerChannelSource getSource(TunerChannel tunerChannel, ChannelSpecification channelSpecification)
     {
         if(isTunable(tunerChannel))
         {
@@ -416,7 +417,7 @@ public class PolyphaseChannelSourceManager extends ChannelSourceManager
                     }
 
                     //If we're successful to here, allocate the channel
-                    return mPolyphaseChannelManager.getChannel(tunerChannel);
+                    return mPolyphaseChannelManager.getChannel(tunerChannel, channelSpecification);
                 }
                 catch(SourceException se)
                 {

src/main/java/io/github/dsheirer/source/tuner/rtl/RTL2832TunerController.java

@@ -95,6 +95,12 @@ public abstract class RTL2832TunerController extends USBTunerController
         mDeviceDescriptor = deviceDescriptor;
     }
 
+    @Override
+    public int getBufferSampleCount()
+    {
+        return getUSBTransferBufferSize(getSampleRate()) / 2; //2 bytes per complex sample
+    }
+
 
     public void init() throws SourceException
     {
@@ -987,17 +993,23 @@ public abstract class RTL2832TunerController extends USBTunerController
 
         if(mUSBTransferProcessor != null)
         {
-            if(sampleRate.getRate() > 300000)
-            {
-                mUSBTransferProcessor.setBufferSize(USB_TRANSFER_BUFFER_SIZE_HIGH_SAMPLE_RATE);
-            }
-            else
-            {
-                mUSBTransferProcessor.setBufferSize(USB_TRANSFER_BUFFER_SIZE_LOW_SAMPLE_RATE);
-            }
+            mUSBTransferProcessor.setBufferSize(getUSBTransferBufferSize(sampleRate.getRate()));
         }
     }
 
+    /**
+     * Determines the size of USB transfer buffers according to the sample rate
+     */
+    private int getUSBTransferBufferSize(double sampleRate)
+    {
+        if(sampleRate > 300000)
+        {
+            return USB_TRANSFER_BUFFER_SIZE_HIGH_SAMPLE_RATE;
+        }
+
+        return USB_TRANSFER_BUFFER_SIZE_LOW_SAMPLE_RATE;
+    }
+
     public void setSampleRateFrequencyCorrection(int ppm) throws SourceException
     {
         int offset = -ppm * TWO_TO_22_POWER / 1000000;

src/main/java/io/github/dsheirer/source/tuner/test/TestTunerController.java

@@ -32,7 +32,7 @@ public class TestTunerController extends TunerController
 
     public static final long MINIMUM_FREQUENCY = 1l;
     public static final long MAXIMUM_FREQUENCY = 1000000000l;
-    public static final int SAMPLE_RATE = 50000;
+    public static final int SAMPLE_RATE = 10000000;
     public static final int DC_NOISE_BANDWIDTH = 0;
     public static final double USABLE_BANDWIDTH_PERCENTAGE = 1.00;
 
@@ -65,6 +65,12 @@ public class TestTunerController extends TunerController
         }
     }
 
+    @Override
+    public int getBufferSampleCount()
+    {
+        return SAMPLE_RATE / SPECTRAL_FRAME_RATE;
+    }
+
     @Override
     public void dispose()
     {

src/main/java/io/github/dsheirer/source/tuner/usb/USBMasterProcessor.java

@@ -81,7 +81,7 @@ public class USBMasterProcessor
         if(mRunning.compareAndSet(false, true))
         {
             //Set periodicity to an odd multiple to avoid contention with transfer buffer receivers
-            mProcessorFuture = ThreadPool.SCHEDULED.scheduleAtFixedRate(mProcessor, 0L, 5L, TimeUnit.MILLISECONDS);
+            mProcessorFuture = ThreadPool.SCHEDULED.scheduleAtFixedRate(mProcessor, 0L, 9L, TimeUnit.MILLISECONDS);
         }
     }
 
@@ -100,6 +100,14 @@ public class USBMasterProcessor
         }
     }
 
+    /**
+     * Stops the libusb timeout processor and prepares for shutdown.
+     */
+    public void shutdown()
+    {
+        stop();
+    }
+
     /**
      * Runnable to invoke LibUSB timeout handler.  All downstream completed transfer processing will occur on this
      * thread instance.

src/main/java/io/github/dsheirer/source/wave/ComplexWaveSource.java

@@ -209,6 +209,11 @@ public class ComplexWaveSource extends ComplexSource implements IControllableFil
 
             if(broadcast && mListener != null)
             {
+                if(samplesRead < 0)
+                {
+                    throw new IOException("End of file reached");
+                }
+
                 if(samplesRead < buffer.length)
                 {
                     buffer = Arrays.copyOf(buffer, samplesRead);