mirror of
https://github.com/DSheirer/sdrtrunk.git
synced 2026-11-12 08:37:25 -05:00
bc5080aa4a
Changed C4FM symbol filter to reset frequency tracking values when the tuner's frequency or PPM values change. Moved all frequency control pieces into the source.tuner.frequency package.
100 lines
3.1 KiB
Java
100 lines
3.1 KiB
Java
/*******************************************************************************
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* SDR Trunk
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* Copyright (C) 2014 Dennis Sheirer
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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******************************************************************************/
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package decode.nbfm;
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import sample.real.RealSampleListener;
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import source.Source.SampleType;
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import audio.AudioOutputImpl;
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import audio.IAudioOutput;
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import decode.Decoder;
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import decode.DecoderType;
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import decode.config.DecodeConfiguration;
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import dsp.filter.DCRemovalFilter2;
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import dsp.nbfm.FilteringNBFMDemodulator;
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public class NBFMDecoder extends Decoder
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{
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/**
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* This value determines how quickly the DC remove filter responds to
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* changes in frequency.
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*/
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private static final double sDC_REMOVAL_RATIO = 0.000003;
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private FilteringNBFMDemodulator mDemodulator;
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private DCRemovalFilter2 mDCRemovalFilter;
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private AudioOutputImpl mAudioOutput = new AudioOutputImpl( "NBFM Decoder Audio Output" );
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public NBFMDecoder( DecodeConfiguration config, SampleType sampleType )
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{
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super( config, sampleType );
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/**
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* Only setup a demod chain if we're receiving complex samples. If
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* we're receiving demodulated samples, they'll be handled the same
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* was as we handle the output of the demodulator.
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*/
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if( mSourceSampleType == SampleType.COMPLEX )
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{
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/**
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* The Decoder super class is both a Complex listener and a float
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* listener. So, we add the demod to listen to the incoming
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* quadrature samples, and we wire the output of the demod right
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* back to this class, so we can receive the demodulated output
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* to process
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*/
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mDemodulator = new FilteringNBFMDemodulator();
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this.addComplexListener( mDemodulator );
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/**
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* Remove the DC component that is present when we're mistuned
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*/
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mDCRemovalFilter = new DCRemovalFilter2( sDC_REMOVAL_RATIO );
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mDemodulator.addListener( mDCRemovalFilter );
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/**
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* Route the demodulated, filtered samples back to this class to send
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* to all registered listeners
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*/
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mDCRemovalFilter.setListener( this.getRealReceiver() );
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}
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addRealSampleListener( mAudioOutput );
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}
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@Override
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public DecoderType getType()
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{
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return DecoderType.NBFM;
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}
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@Override
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public void addUnfilteredRealSampleListener( RealSampleListener listener )
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{
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if( mDemodulator != null )
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{
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mDemodulator.addListener( listener );
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}
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}
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@Override
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public IAudioOutput getAudioOutput()
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{
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return mAudioOutput;
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}
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}
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