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#1291 Updates DC removal processing across tuner sample streams to run on a periodic timer to reduce overall processing requirements. Updates build version to 0.5.0 beta 5 (#1292)

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Co-authored-by: Dennis Sheirer <dsheirer@github.com>
This commit is contained in:
Denny Sheirer
2022-07-23 08:14:31 -04:00
committed by GitHub
parent 414ba25d61
commit 48a93990e8
7 changed files with 330 additions and 72 deletions
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49
src/main/java/io/github/dsheirer/buffer/airspy/ScalarUnpackedSampleConverter.java
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@@ -19,6 +19,7 @@
package io.github.dsheirer.buffer.airspy;
import io.github.dsheirer.buffer.DcCorrectionManager;
import java.nio.ByteBuffer;
/**
@@ -26,34 +27,50 @@ import java.nio.ByteBuffer;
*/
public class ScalarUnpackedSampleConverter implements IAirspySampleConverter
{
private static final float DC_FILTER_GAIN = 0.007f; //Normalizes DC over period of ~142 (1 / .007) buffers
private float mAverageDc = 0.0f;
/**
* Manages DC calculations and processing interval
*/
private DcCorrectionManager mDcCalculationManager = new DcCorrectionManager();
@Override
public short[] convert(ByteBuffer buffer)
{
boolean shouldCalculateDc = mDcCalculationManager.shouldCalculateDc();
int offset = 0;
long dcAccumulator = 0;
short sample;
short[] samples;
byte b1, b2;
samples = new short[buffer.capacity() / 2];
for(int x = 0; x < samples.length; x++)
if(shouldCalculateDc)
{
b1 = buffer.get(offset++);
b2 = buffer.get(offset++);
sample = (short)(((b2 & 0x0F) << 8) | (b1 & 0xFF));
samples[x] = sample;
dcAccumulator += sample;
}
long dcAccumulator = 0;
//Calculate the average scaled DC offset so that it can be applied in the native buffer's converted samples
float averageDcNow = ((float)dcAccumulator / (float)samples.length) - 2048.0f;
averageDcNow *= AirspyBufferIterator.SCALE_SIGNED_12_BIT_TO_FLOAT;
averageDcNow -= mAverageDc;
mAverageDc += (averageDcNow * DC_FILTER_GAIN);
for(int x = 0; x < samples.length; x++)
{
b1 = buffer.get(offset++);
b2 = buffer.get(offset++);
sample = (short)(((b2 & 0x0F) << 8) | (b1 & 0xFF));
samples[x] = sample;
dcAccumulator += sample;
}
float averageDcNow = ((float)dcAccumulator / (float)samples.length) - 2048.0f;
averageDcNow *= AirspyBufferIterator.SCALE_SIGNED_12_BIT_TO_FLOAT;
mDcCalculationManager.adjust(averageDcNow);
}
else
{
for(int x = 0; x < samples.length; x++)
{
b1 = buffer.get(offset++);
b2 = buffer.get(offset++);
sample = (short)(((b2 & 0x0F) << 8) | (b1 & 0xFF));
samples[x] = sample;
}
}
return samples;
}
@@ -61,6 +78,6 @@ public class ScalarUnpackedSampleConverter implements IAirspySampleConverter
@Override
public float getAverageDc()
{
return mAverageDc;
return mDcCalculationManager.getAverageDc();
}
}