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NBFM Channel level CTCSS/DCS and audio features (#2425)

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NBFM decoder enhancements.  CTCSS and DCS squelch control.  Adds deemphasis, high pass filter control, and auto-level control
This commit is contained in:
Randy
2026-09-26 00:54:31 -06:00
committed by GitHub
parent 80360029ef
commit 97cae50bdd
34 changed files with 2377 additions and 217 deletions
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53
src/main/java/io/github/dsheirer/audio/AudioModule.java
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@@ -32,6 +32,8 @@ import io.github.dsheirer.sample.real.IRealBufferListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.List;
/**
* Provides packaging of demodulated audio sample buffers into audio segments for broadcast to registered listeners.
* Includes audio packet metadata in constructed audio segments.
@@ -42,36 +44,7 @@ public class AudioModule extends AbstractAudioModule implements ISquelchStateLis
Listener<float[]>
{
private static final Logger mLog = LoggerFactory.getLogger(AudioModule.class);
private static float[] sHighPassFilterCoefficients;
private final boolean mAudioFilterEnable;
static
{
FIRFilterSpecification specification = FIRFilterSpecification.highPassBuilder()
.sampleRate(8000)
.stopBandCutoff(200)
.stopBandAmplitude(0.0)
.stopBandRipple(0.025)
.passBandStart(300)
.passBandAmplitude(1.0)
.passBandRipple(0.01)
.build();
try
{
RemezFIRFilterDesigner designer = new RemezFIRFilterDesigner(specification);
if(designer.isValid())
{
sHighPassFilterCoefficients = designer.getImpulseResponse();
}
}
catch(FilterDesignException fde)
{
mLog.error("Filter design error", fde);
}
}
private final IRealFilter mHighPassFilter = FilterFactory.getRealFilter(sHighPassFilterCoefficients);
private List<AbstractAudioFilter>mAudioFilters;
private final SquelchStateListener mSquelchStateListener = new SquelchStateListener();
private SquelchState mSquelchState = SquelchState.SQUELCH;
@@ -81,23 +54,23 @@ public class AudioModule extends AbstractAudioModule implements ISquelchStateLis
* @param aliasList for aliasing identifiers
* @param timeslot for this audio module
* @param maxAudioSegmentLength in milliseconds
* @param audioFilterEnable to enable or disable high-pass audio filter
* @param audioFilters a list of audio filters to apply to the incoming audio samples
*/
public AudioModule(AliasList aliasList, int timeslot, long maxAudioSegmentLength, boolean audioFilterEnable)
public AudioModule(AliasList aliasList, int timeslot, long maxAudioSegmentLength, List<AbstractAudioFilter> audioFilters)
{
super(aliasList, timeslot, maxAudioSegmentLength);
mAudioFilterEnable = audioFilterEnable;
mAudioFilters = audioFilters;
}
/**
* Creates an Audio Module.
* @param aliasList for aliasing identifiers
* @param audioFilterEnable to enable or disable high-pass audio filter
* @param audioFilters a list of audio filters to apply to the incoming audio samples
*/
public AudioModule(AliasList aliasList, boolean audioFilterEnable)
public AudioModule(AliasList aliasList, List<AbstractAudioFilter> audioFilters)
{
super(aliasList);
mAudioFilterEnable = audioFilterEnable;
mAudioFilters = audioFilters;
}
@Override
@@ -128,9 +101,13 @@ public class AudioModule extends AbstractAudioModule implements ISquelchStateLis
{
if(mSquelchState == SquelchState.UNSQUELCH)
{
if(mAudioFilterEnable)
// apply audio filters if any (i.e. deemphasis, high pass, etc.)
if(!mAudioFilters.isEmpty())
{
audioBuffer = mHighPassFilter.filter(audioBuffer);
for(AbstractAudioFilter filter : mAudioFilters)
{
audioBuffer = filter.filter(audioBuffer);
}
}
addAudio(audioBuffer);