diff --git a/src/main/java/io/github/dsheirer/module/decode/p25/Trellis_3_4_Rate.java b/src/main/java/io/github/dsheirer/module/decode/p25/Trellis_3_4_Rate.java
index cea87249..cc38fa45 100644
--- a/src/main/java/io/github/dsheirer/module/decode/p25/Trellis_3_4_Rate.java
+++ b/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 
diff --git a/src/main/java/io/github/dsheirer/source/tuner/channel/CICTunerChannelSource.java b/src/main/java/io/github/dsheirer/source/tuner/channel/CICTunerChannelSource.java
index 9253200b..e15cdfbc 100644
--- a/src/main/java/io/github/dsheirer/source/tuner/channel/CICTunerChannelSource.java
+++ b/src/main/java/io/github/dsheirer/source/tuner/channel/CICTunerChannelSource.java
@@ -18,7 +18,7 @@ package io.github.dsheirer.source.tuner.channel;
 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.dsp.mixer.Oscillator;
 import io.github.dsheirer.sample.IOverflowListener;
 import io.github.dsheirer.sample.Listener;
 import io.github.dsheirer.sample.buffer.OverflowableReusableBufferTransferQueue;
@@ -81,7 +81,7 @@ public class CICTunerChannelSource extends TunerChannelSource implements Listene
         mTunerFrequency = tunerChannel.getFrequency();
         long frequencyOffset = mTunerFrequency - getTunerChannel().getFrequency();
 
-        mFrequencyCorrectionMixer = new LowPhaseNoiseOscillator(frequencyOffset, sampleRate);
+        mFrequencyCorrectionMixer = new Oscillator(frequencyOffset, sampleRate);
     }
 
     /**
diff --git a/src/main/java/io/github/dsheirer/source/tuner/channel/TunerChannelSource.java b/src/main/java/io/github/dsheirer/source/tuner/channel/TunerChannelSource.java
index 57b0abaf..8a8efac4 100644
--- a/src/main/java/io/github/dsheirer/source/tuner/channel/TunerChannelSource.java
+++ b/src/main/java/io/github/dsheirer/source/tuner/channel/TunerChannelSource.java
@@ -286,8 +286,22 @@ 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);
+                }
+                try
+                {
+                    processSamples();
+                }
+                catch(Throwable t)
+                {
+                    mLog.error("Error while processing samples", t);
+                }
             }
 
             if(mStopped)
@@ -300,8 +314,15 @@ public abstract class TunerChannelSource extends ComplexSource implements ISourc
 
                 mScheduledFuture = null;
 
-                getHeartbeatManager().broadcast();
-                performDisposal();
+                try
+                {
+                    getHeartbeatManager().broadcast();
+                    performDisposal();
+                }
+                catch(Throwable t)
+                {
+                    mLog.error("Error during final shutdown processing of samples", t);
+                }
             }
         }
     }