/*******************************************************************************
* 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/>
******************************************************************************/
package module.decode.mdc1200;
import instrument.Instrumentable;
import instrument.tap.Tap;
import instrument.tap.TapGroup;
import instrument.tap.stream.BinaryTap;
import instrument.tap.stream.FloatBufferTap;
import instrument.tap.stream.FloatTap;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ScheduledExecutorService;
import module.decode.Decoder;
import module.decode.DecoderType;
import sample.Listener;
import sample.real.IFilteredRealBufferListener;
import sample.real.RealBuffer;
import alias.AliasList;
import bits.MessageFramer;
import bits.SyncPattern;
import dsp.NRZDecoder;
import dsp.filter.Filters;
import dsp.filter.fir.real.RealFIRFilter_RB_RB;
import dsp.filter.halfband.real.HalfBandFilter_RB_RB;
import dsp.fsk.FSK2Decoder;
import dsp.fsk.FSK2Decoder.Output;
/**
* MDC1200 Decoder - 1200 baud 2FSK decoder that can process 48k sample rate
* complex or floating point samples and output fully framed MDC1200 messages
*/
public class MDCDecoder extends Decoder implements IFilteredRealBufferListener,
Instrumentable
{
/* Decimated sample rate ( 48,000 / 2 = 24,000 ) feeding the decoder */
private static final int sDECIMATED_SAMPLE_RATE = 24000;
/* Baud or Symbol Rate */
private static final int sSYMBOL_RATE = 1200;
/* Message length */
private static final int sMESSAGE_LENGTH = 304;
/* Instrumentation Taps */
private ArrayList<TapGroup> mAvailableTaps;
private static final String INSTRUMENT_BANDPASS_FILTER_TO_FSK2_DEMOD =
"Tap Point: Bandpass Filter > < FSK2 Decoder";
private static final String INSTRUMENT_FSK2_DECODER_TO_NRZ_DECODER =
"Tap Point: FSK2 Decoder > < NRZI Decoder";
private static final String INSTRUMENT_NRZI_DECODER_TO_MESSAGE_FRAMER =
"Tap Point: NRZ Decoder > < Message Framer";
private FSK2Decoder mFSKDecoder;
private HalfBandFilter_RB_RB mDecimationFilter;
private RealFIRFilter_RB_RB mBandPassFilter;
private NRZDecoder mNRZDecoder;
private MessageFramer mMessageFramer;
private MDCMessageProcessor mMessageProcessor;
public MDCDecoder( AliasList aliasList )
{
/* Decimation filter: 48000 / 2 = 24000 */
mDecimationFilter = new HalfBandFilter_RB_RB(
Filters.FIR_HALF_BAND_31T_ONE_EIGHTH_FCO.getCoefficients(), 1.0f, true );
/* Bandpass filter - predefined */
mBandPassFilter = new RealFIRFilter_RB_RB(
Filters.FIRBP_1200FSK_24000FS.getCoefficients(), 1.02f );
mDecimationFilter.setListener( mBandPassFilter );
/* 2FSK Decoder */
mFSKDecoder = new FSK2Decoder( sDECIMATED_SAMPLE_RATE,
sSYMBOL_RATE, Output.NORMAL );
mBandPassFilter.setListener( mFSKDecoder );
/* NRZ Decoder */
mNRZDecoder = new NRZDecoder( NRZDecoder.MODE_INVERTED );
mFSKDecoder.setListener( mNRZDecoder );
/* Message Framer */
mMessageFramer = new MessageFramer( SyncPattern.MDC1200.getPattern(),
sMESSAGE_LENGTH );
mNRZDecoder.setListener( mMessageFramer );
/* Message Processor */
mMessageProcessor = new MDCMessageProcessor( aliasList );
mMessageFramer.addMessageListener( mMessageProcessor );
mMessageProcessor.addMessageListener( this );
}
public void dispose()
{
super.dispose();
mDecimationFilter.dispose();
mBandPassFilter.dispose();
mFSKDecoder.dispose();
mNRZDecoder.dispose();
mMessageFramer.dispose();
mMessageProcessor.dispose();
}
/* Instrumentation */
@Override
public List<TapGroup> getTapGroups()
{
if( mAvailableTaps == null )
{
mAvailableTaps = new ArrayList<TapGroup>();
TapGroup group = new TapGroup( "MDC-1200 Decoder" );
group.add(
new FloatTap( INSTRUMENT_BANDPASS_FILTER_TO_FSK2_DEMOD, 0, 0.5f ) );
group.add(
new BinaryTap( INSTRUMENT_FSK2_DECODER_TO_NRZ_DECODER, 0, 0.025f ) );
group.add(
new BinaryTap( INSTRUMENT_NRZI_DECODER_TO_MESSAGE_FRAMER, 0, 0.025f ) );
mAvailableTaps.add( group );
mAvailableTaps.addAll( mFSKDecoder.getTapGroups() );
}
return mAvailableTaps;
}
@Override
public void registerTap( Tap tap )
{
mFSKDecoder.registerTap( tap );
switch( tap.getName() )
{
case INSTRUMENT_BANDPASS_FILTER_TO_FSK2_DEMOD:
/* wire the tap between the bandpass filter and the demod */
FloatBufferTap floatTap = (FloatBufferTap)tap;
mBandPassFilter.setListener( floatTap );
floatTap.setListener( mFSKDecoder );
break;
case INSTRUMENT_FSK2_DECODER_TO_NRZ_DECODER:
/* wire between FSK2 decoder and NRZ decoder */
BinaryTap binTap = (BinaryTap)tap;
mFSKDecoder.setListener( binTap );
binTap.setListener( mNRZDecoder );
break;
case INSTRUMENT_NRZI_DECODER_TO_MESSAGE_FRAMER:
/* wire between demod and framer */
BinaryTap binInvTap = (BinaryTap)tap;
mNRZDecoder.setListener( binInvTap );
binInvTap.setListener( mMessageFramer );
break;
default:
}
}
@Override
public void unregisterTap( Tap tap )
{
mFSKDecoder.unregisterTap( tap );
switch( tap.getName() )
{
case INSTRUMENT_BANDPASS_FILTER_TO_FSK2_DEMOD:
mBandPassFilter.setListener( mFSKDecoder );
break;
case INSTRUMENT_FSK2_DECODER_TO_NRZ_DECODER:
mFSKDecoder.setListener( mNRZDecoder );
break;
case INSTRUMENT_NRZI_DECODER_TO_MESSAGE_FRAMER:
mNRZDecoder.setListener( mMessageFramer );
break;
default:
}
}
@Override
public DecoderType getDecoderType()
{
return DecoderType.MDC1200;
}
@Override
public Listener<RealBuffer> getFilteredRealBufferListener()
{
return mDecimationFilter;
}
@Override
public void reset()
{
// TODO Auto-generated method stub
}
@Override
public void start( ScheduledExecutorService executor )
{
// TODO Auto-generated method stub
}
@Override
public void stop()
{
// TODO Auto-generated method stub
}
}