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39 - Adds P25/LSM support to the DemodulatorViewerFX application and

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adds Feed forward gain support to the C4FM DQPSK demodulator which seems
to improve output from the interpolating sample buffer at each symbol
period.  Updates the symbol timing gain for C4FM to decrease the gain a
bit since the feed forward gain is providing a better interpolated symbol.
This commit is contained in:
Denny
2018-03-24 11:03:18 -04:00
parent bfaacb309d
commit c36f6901af
16 changed files with 130 additions and 76 deletions
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33
src/main/java/io/github/dsheirer/dsp/gain/ComplexFeedForwardGainControl.java
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@@ -29,7 +29,7 @@ public class ComplexFeedForwardGainControl implements ComplexSampleListener
private ComplexSampleListener mListener;
private FloatCircularBuffer mEnvelopeHistory;
private ReusableBufferQueue mReusableBufferQueue = new ReusableBufferQueue();
private ReusableBufferQueue mReusableBufferQueue = new ReusableBufferQueue("ComplexFeedForwardGainControl");
private float mMaxEnvelope = 0.0f;
private float mGain = 1.0f;
@@ -155,11 +155,36 @@ public class ComplexFeedForwardGainControl implements ComplexSampleListener
*/
public ReusableComplexBuffer filter(ReusableComplexBuffer buffer)
{
float[] filtered = filter(buffer.getSamples());
float[] samples = buffer.getSamples();
ReusableComplexBuffer filteredBuffer = mReusableBufferQueue.getBuffer(filtered.length);
ReusableComplexBuffer filteredBuffer = mReusableBufferQueue.getBuffer(samples.length);
filteredBuffer.setTimestamp(buffer.getTimestamp());
filteredBuffer.reloadFrom(filtered, buffer.getTimestamp());
float[] filtered = filteredBuffer.getSamples();
mMaxEnvelope = MINIMUM_ENVELOPE;
float currentEnvelope;
for(int x = 0; x < samples.length; x += 2)
{
currentEnvelope = Complex.envelope(samples[x], samples[x + 1]);
if(currentEnvelope > mMaxEnvelope)
{
mMaxEnvelope = currentEnvelope;
}
}
adjustGain();
for(int x = 0; x < samples.length; x += 2)
{
filtered[x] = samples[x] * mGain;
filtered[x + 1] = samples[x + 1] * mGain;
}
buffer.decrementUserCount();
filteredBuffer.incrementUserCount();
return filteredBuffer;