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Changed NID error detection and correction (edac) to using Berlekemp Massey 63-bit block decoder for the BCH(63,16,11) code so that we can correct up to 11 bit errors in a NID (versus previous 2).

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dennis.sheirer
2015-01-04 15:29:34 +00:00
parent bb27d5cb42
commit 84261a4be9
7 changed files with 145 additions and 74 deletions
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6
src/dsp/fsk/P25MessageFramer.java
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@@ -28,6 +28,7 @@ import decode.p25.message.tdu.lc.TDULinkControlMessage;
import decode.p25.message.tsbk.TSBKMessage;
import decode.p25.message.tsbk.TSBKMessageFactory;
import decode.p25.reference.DataUnitID;
import edac.BCH_63_16_11;
import edac.CRC;
import edac.CRCP25;
@@ -60,6 +61,7 @@ public class P25MessageFramer implements Listener<Dibit>
private SyncPatternMatcher mMatcher;
private boolean mInverted = false;
private TrellisHalfRate mHalfRate = new TrellisHalfRate();
private BCH_63_16_11 mNIDDecoder = new BCH_63_16_11();
/**
* Constructs a C4FM message framer to receive a stream of C4FM symbols and
@@ -229,14 +231,14 @@ public class P25MessageFramer implements Listener<Dibit>
switch( mDUID )
{
case NID:
CRC crc = CRCP25.correctNID( mMessage );
CRC crc = mNIDDecoder.correctNID( mMessage );
if( crc != CRC.FAILED_CRC )
{
int value = mMessage.getInt( P25Message.DUID );
DataUnitID duid = DataUnitID.fromValue( value );
if( duid != DataUnitID.UNKN )
{
setDUID( duid );