/*******************************************************************************
* sdrtrunk
* Copyright (C) 2014-2017 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.mpt1327;
import alias.AliasList;
import bits.MessageFramer;
import bits.SyncPattern;
import dsp.filter.FilterFactory;
import dsp.filter.Filters;
import dsp.filter.fir.FIRFilterSpecification;
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;
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 module.decode.Decoder;
import module.decode.DecoderType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import sample.Broadcaster;
import sample.Listener;
import sample.real.IFilteredRealBufferListener;
import sample.real.RealBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ScheduledExecutorService;
/**
* MPT1327 Decoder - 1200 baud 2FSK decoder that can process 48k sample rate
* complex or floating point samples and output fully framed MPT1327 control and
* traffic messages.
*/
public class MPT1327Decoder extends Decoder implements IFilteredRealBufferListener, Instrumentable
{
private final static Logger mLog = LoggerFactory.getLogger(MPT1327Decoder.class);
private static final FIRFilterSpecification HIGH_PASS_SPECIFICATION = FIRFilterSpecification.highPassBuilder()
.sampleRate( 24000 )
.stopBandCutoff( 800 )
.stopBandAmplitude( 0.0 )
.stopBandRipple( 0.03 )
.passBandStart( 1000 )
.passBandAmplitude( 1.0 )
.passBandRipple( 0.08 )
.build();
private static float[] HIGHPASS_FILTER;
static
{
try
{
HIGHPASS_FILTER = FilterFactory.getTaps(HIGH_PASS_SPECIFICATION);
}
catch(Exception e)
{
mLog.error("Couldn't design MPT1327 highpass filter");
}
}
/* 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 -- longest possible message is:
* 4xREVS + 16xSYNC + 64xADD1 + 64xDCW1 + 64xDCW2 + 64xDCW3 + 64xDCW4 */
private static final int sMESSAGE_LENGTH = 350;
/* Instrumentation Taps */
private static final String INSTRUMENT_HB1_FILTER_TO_HIGH_PASS =
"Tap Point: Half-band Decimation Filter > < Low Pass Filter";
private static final String INSTRUMENT_HIGH_PASS_TO_DECODER =
"Tap Point: Low Pass Filter > < Decoder";
private static final String INSTRUMENT_DECODER_TO_FRAMER =
"Tap Point: Decoder > < Sync Detect/Message Framer";
private List<TapGroup> mAvailableTaps;
private HalfBandFilter_RB_RB mDecimationFilter;
private RealFIRFilter_RB_RB mHighPassFilter;
private FSK2Decoder mFSKDecoder;
private Broadcaster<Boolean> mSymbolBroadcaster;
private MessageFramer mControlMessageFramer;
private MessageFramer mTrafficMessageFramer;
private MPT1327MessageProcessor mMessageProcessor;
public MPT1327Decoder(AliasList aliasList, Sync sync)
{
/**
* Normal: 2FSK Decoder with inverted output
* French: 2FSK Decoder with normal output
*/
if(sync == Sync.NORMAL)
{
mFSKDecoder = new FSK2Decoder(24000, 1200, Output.INVERTED);
}
else if(sync == Sync.FRENCH)
{
mFSKDecoder = new FSK2Decoder(24000, 1200, Output.NORMAL);
}
else
{
throw new IllegalArgumentException("MPT1327 Decoder - unrecognized Sync type");
}
/* Decimation filter - 48000 / 2 = 24000 output */
mDecimationFilter = new HalfBandFilter_RB_RB(Filters.FIR_HALF_BAND_31T_ONE_EIGHTH_FCO.getCoefficients(), 1.0002f, true);
//High-pass filter the audio to remove any DC component or CTCSS tones. The audio has already been low-pass
//filtered by the AudioDemodulation filter cutoff of 3400 Hz.
mHighPassFilter = new RealFIRFilter_RB_RB(HIGHPASS_FILTER, 1.0f);
mDecimationFilter.setListener(mHighPassFilter);
mHighPassFilter.setListener(mFSKDecoder);
mSymbolBroadcaster = new Broadcaster<Boolean>();
mFSKDecoder.setListener(mSymbolBroadcaster);
/* Message framer for control channel messages */
mControlMessageFramer = new MessageFramer(sync.getControlSyncPattern().getPattern(), sMESSAGE_LENGTH);
mSymbolBroadcaster.addListener(mControlMessageFramer);
/* Message framer for traffic channel massages */
mTrafficMessageFramer = new MessageFramer(sync.getTrafficSyncPattern().getPattern(), sMESSAGE_LENGTH);
mSymbolBroadcaster.addListener(mTrafficMessageFramer);
/* Fully decoded and framed messages processor */
mMessageProcessor = new MPT1327MessageProcessor(aliasList);
mMessageProcessor.setMessageListener(this);
mControlMessageFramer.addMessageListener(mMessageProcessor);
mTrafficMessageFramer.addMessageListener(mMessageProcessor);
}
@Override
public Listener<RealBuffer> getFilteredRealBufferListener()
{
return mDecimationFilter;
}
@Override
public DecoderType getDecoderType()
{
return DecoderType.MPT1327;
}
/**
* Cleanup method
*/
public void dispose()
{
super.dispose();
mSymbolBroadcaster.dispose();
mControlMessageFramer.dispose();
mFSKDecoder.dispose();
mDecimationFilter.dispose();
mMessageProcessor.dispose();
mTrafficMessageFramer.dispose();
}
/* Instrumentation Taps */
@Override
public List<TapGroup> getTapGroups()
{
if(mAvailableTaps == null)
{
mAvailableTaps = new ArrayList<TapGroup>();
TapGroup group = new TapGroup("MPT-1327 Decoder");
group.add(new FloatTap(INSTRUMENT_HB1_FILTER_TO_HIGH_PASS, 0, 0.5f));
group.add(new FloatTap(INSTRUMENT_HIGH_PASS_TO_DECODER, 0, 0.5f));
group.add(new BinaryTap(INSTRUMENT_DECODER_TO_FRAMER, 0, 0.025f));
mAvailableTaps.add(group);
/* Add the taps from the FSK decoder */
mAvailableTaps.addAll(mFSKDecoder.getTapGroups());
}
return mAvailableTaps;
}
@Override
public void registerTap(Tap tap)
{
/* Send request to decoder */
mFSKDecoder.registerTap(tap);
switch(tap.getName())
{
case INSTRUMENT_HB1_FILTER_TO_HIGH_PASS:
FloatBufferTap hb1Tap = (FloatBufferTap) tap;
mDecimationFilter.setListener(hb1Tap);
hb1Tap.setListener(mHighPassFilter);
break;
case INSTRUMENT_HIGH_PASS_TO_DECODER:
FloatBufferTap lowTap = (FloatBufferTap) tap;
mHighPassFilter.setListener(lowTap);
lowTap.setListener(mFSKDecoder);
break;
case INSTRUMENT_DECODER_TO_FRAMER:
BinaryTap decoderTap = (BinaryTap) tap;
mFSKDecoder.setListener(decoderTap);
decoderTap.setListener(mSymbolBroadcaster);
break;
}
}
@Override
public void unregisterTap(Tap tap)
{
mFSKDecoder.unregisterTap(tap);
switch(tap.getName())
{
case INSTRUMENT_HB1_FILTER_TO_HIGH_PASS:
mDecimationFilter.setListener(mHighPassFilter);
break;
case INSTRUMENT_HIGH_PASS_TO_DECODER:
mHighPassFilter.setListener(mFSKDecoder);
break;
case INSTRUMENT_DECODER_TO_FRAMER:
mFSKDecoder.setListener(mSymbolBroadcaster);
break;
}
}
public enum Sync
{
NORMAL("Normal", SyncPattern.MPT1327_CONTROL, SyncPattern.MPT1327_TRAFFIC),
FRENCH("French", SyncPattern.MPT1327_CONTROL_FRENCH, SyncPattern.MPT1327_TRAFFIC_FRENCH);
private String mLabel;
private SyncPattern mControlSyncPattern;
private SyncPattern mTrafficSyncPattern;
private Sync(String label, SyncPattern controlPattern, SyncPattern trafficPattern)
{
mLabel = label;
mControlSyncPattern = controlPattern;
mTrafficSyncPattern = trafficPattern;
}
public String getLabel()
{
return mLabel;
}
public SyncPattern getControlSyncPattern()
{
return mControlSyncPattern;
}
public SyncPattern getTrafficSyncPattern()
{
return mTrafficSyncPattern;
}
public String toString()
{
return getLabel();
}
}
@Override
public void reset()
{
mControlMessageFramer.reset();
mTrafficMessageFramer.reset();
}
@Override
public void start(ScheduledExecutorService executor)
{
// TODO Auto-generated method stub
}
@Override
public void stop()
{
// TODO Auto-generated method stub
}
}